Enclosed nests may provide greater thermal than nest predation benefits compared with open nests across latitudes

Science.gov (United States)

Martin, Thomas E.; Boyce, Andy J.; Fierro-Calderon, Karolina; Mitchell, Adam E.; Armstad, Connor E.; Mouton, James C.; Bin Soudi, Evertius E.

2017-01-01

Nest structure is thought to provide benefits that have fitness consequences for several taxa. Traditionally, reduced nest predation has been considered the primary benefit underlying evolution of nest structure, whereas thermal benefits have been considered a secondary or even non-existent factor. Yet, the relative roles of these factors on nest structures remain largely unexplored.Enclosed nests have a constructed or natural roof connected to sides that allow a restricted opening or tube entrance that provides cover in all directions except the entrance, whereas open nests are cups or platforms that are open above. We show that construction of enclosed nests is more common among songbirds (Passeriformes) in tropical and southern hemisphere regions than in north temperate regions. This geographic pattern may reflect selection from predation risk, under long-standing assumptions that nest predation rates are higher in southern regions and that enclosed nests reduce predation risk compared with open cup nests. We therefore compared nest predation rates between enclosed vs. open nests in 114 songbird species that do not nest in tree holes among five communities of coexisting birds, and for 205 non-hole-nesting species from the literature, across northern temperate, tropical, and southern hemisphere regions.Among coexisting species, enclosed nests had lower nest predation rates than open nests in two south temperate sites, but not in either of two tropical sites or a north temperate site. Nest predation did not differ between nest types at any latitude based on literature data. Among 319 species from both our field studies and the literature, enclosed nests did not show consistent benefits of reduced predation and, in fact, predation was not consistently higher in the tropics, contrary to long-standing perspectives.Thermal benefits of enclosed nests were indicated based on three indirect results. First, species that built enclosed nests were smaller than species using

Factors affecting the reproductive success of American Oystercatchers Haematopus palliatus on the outer banks of North Carolina

Science.gov (United States)

Schulte, Shiloh A.; Simons, Theodore R.

2015-01-01

We used an information-theoretic approach to assess the factors affecting the reproductive success of American Oystercatchers Haematopus palliatus on the Outer Banks of North Carolina. We evaluated survival with respect to nesting island, year, time of season, brood age, distance to tide (m), presence of off-road vehicles and proximity of foraging habitat. The daily nest survival (mean 0.981, standard error [SE] 0.002) was affected by year and island, and declined over the nesting season. Mammals were responsible for 54% of identified nest failures. Daily brood survival (mean 0.981, SE 0.002) varied by island and increased non-linearly with age, with highest mortality in the seven days after hatching. Model results indicate direct access to foraging sites has a positive effect on brood survival, whereas presence of off-road vehicles has a negative effect. We studied chick behavior and survival using radio telemetry and direct observation and found that vehicles caused mortality and affected behavior and resource use by oystercatcher chicks. We identified the source of mortality for 37 radio-tagged chicks. Six (16%) were killed by vehicles, 21 (57%) by predators, and 10 (27%) by exposure and starvation. From 1995 to 2008, 25 additional oystercatcher chicks were found dead, 13 (52%) killed by vehicles. Chicks on beaches closed to vehicles used beach and intertidal zones more frequently than chicks on beaches open to vehicles. Chick predators included Great Horned Owls Bubo virginianus, Fish Crows Corvus ossifragus, cats Felis catus, mink Mustela vison, raccoons Procyon lotor, and ghost crabs Ocypode albicans. The factors affecting reproductive success differed between the incubation and chick-rearing stages.  Management actions that influence chick survival will have a larger effect on total productivity than actions affecting nest survival.

Habitat structure and diversity influence the nesting success of an endangered large cavity-nesting bird, the Southern Ground-hornbill

OpenAIRE

Combrink, Leigh; Combrink, Hendrik J.; Botha, André J.; Downs, Colleen T.

2017-01-01

Habitat features can have a profound effect on the nesting success of birds. Savannas are often managed with predators and large herbivores as priority species, with little thought to the many bird species that management decisions could affect. Using a data set spanning seven breeding seasons, we examined how nesting success of Southern Ground-hornbills (SGHs) Bucorvus leadbeateri in the Kruger National Park varied as a result of various environmental and habitat factors within a radius of 3...

CO2 efflux from subterranean nests of ant communities in a seasonal tropical forest, Thailand.

Science.gov (United States)

Hasin, Sasitorn; Ohashi, Mizue; Yamada, Akinori; Hashimoto, Yoshiaki; Tasen, Wattanachai; Kume, Tomonori; Yamane, Seiki

2014-10-01

Many ant species construct subterranean nests. The presence of their nests may explain soil respiration "hot spots", an important factor in the high CO2 efflux from tropical forests. However, no studies have directly measured CO2 efflux from ant nests. We established 61 experimental plots containing 13 subterranean ant species to evaluate the CO2 efflux from subterranean ant nests in a tropical seasonal forest, Thailand. We examined differences in nest CO2 efflux among ant species. We determined the effects of environmental factors on nest CO2 efflux and calculated an index of nest structure. The mean CO2 efflux from nests was significantly higher than those from the surrounding soil in the wet and dry seasons. The CO2 efflux was species-specific, showing significant differences among the 13 ant species. The soil moisture content significantly affected nest CO2 efflux, but there was no clear relationship between nest CO2 efflux and nest soil temperature. The diameter of the nest entrance hole affected CO2 efflux. However, there was no significant difference in CO2 efflux rates between single-hole and multiple-hole nests. Our results suggest that in a tropical forest ecosystem the increase in CO2 efflux from subterranean ant nests is caused by species-specific activity of ants, the nest soil environment, and nest structure.

Interaction in Balanced Cross Nested Designs

Science.gov (United States)

Ramos, Paulo; Mexia, João T.; Carvalho, Francisco; Covas, Ricardo

2011-09-01

Commutative Jordan Algebras, CJA, are used in the study of mixed models obtained, through crossing and nesting, from simpler ones. In the study of cross nested models the interaction between nested factors have been systematically discarded. However this can constitutes an artificial simplification of the models. We point out that, when two crossed factors interact, such interaction is symmetric, both factors playing in it equivalent roles, while when two nested factors interact, the interaction is determined by the nesting factor. These interactions will be called interactions with nesting. In this work we present a coherent formulation of the algebraic structure of models enabling the choice of families of interactions between cross and nested factors using binary operations on CJA.

Nest ectoparasites increase physiological stress in breeding birds: an experiment.

Science.gov (United States)

Martínez-de la Puente, Josué; Merino, Santiago; Tomás, Gustavo; Moreno, Juan; Morales, Judith; Lobato, Elisa; Martínez, Javier

2011-02-01

Parasites are undoubtedly a biotic factor that produces stress. Heat shock proteins (HSPs) are important molecules buffering cellular damage under adverse conditions. During the breeding season, blue tit Cyanistes caeruleus (L.) adults are affected by blood parasites, nest-dwelling parasites and biting flies, potentially affecting their HSP-mediated responses. Here, we treated females with primaquine to reduce blood parasites and fumigated nests with permethrin to reduce nest-dwelling parasites to test whether these treatments affect HSP60 level during the breeding season. Medicated females, but not controls, had a significant reduction of the intensity of infection by Haemoproteus spp. blood parasites. However, final intensity of infection did not differ significantly between groups, and we did not find an effect of medication on change in HSP60 level. Fumigation reduced the abundance of nest-dwelling parasites (mites, fleas and blowfly larvae) and engorged biting midges in nests. Females breeding in non-fumigated nests increased HSP60 levels during the season more than those breeding in fumigated nests. Furthermore, the change in HSP60 level was positively correlated with the abundance of biting midges. These results show how infections by nest ectoparasites during the breeding period can increase the level of HSPs and suggest that biting midges impose physiological costs on breeding female blue tits. Although plausible, the alternative that biting midges prefer to feed on more stressed birds is poorly supported by previous studies.

Nest-site Selection of the Greater Painted Snipe (Rostratula benghalensis benghalensis in Fallow Fields of I-Lan, Taiwan

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Yu-Hsun Hsu

2011-09-01

Full Text Available Nest site quality often affects nest success and the fitness of avian breeders. Vegetation structure and water depth are possible factors evaluated in nest-site selection by ground nesting birds in wetlands. Vegetation structure may affect the predation risk, and water depth is linked to the possibility of being flooded. We examined these two factors in the nest site selection of a wetland bird, the Greater Painted Snipe (Rostratula benghalensis benghalensis, in I-Lan, Taiwan. We found 17 Greater Painted Snipe nests in wet fallow fields. By paired comparisons, we found the breeders tended to nest on sites with higher vegetation coverage and lower water depth than random sites. No significant difference was found in the vegetation height between the nest sites and the paired random sites. Five nests failed to hatch due to flooding or predation. The preference for nest sites with low water depth may be an effort to avoid being flooded and the preference for dense vegetation coverage at nest sites may be a response to predation risk.

Determinants of abundance and effects of blood-sucking flying insects in the nest of a hole-nesting bird

NARCIS (Netherlands)

Tomás, G.; Merino, S.; Martínez-de la Puente, J.; Moreno, J.; Morales, J.; Lobato, E.

2008-01-01

Compared to non-flying nest-dwelling ectoparasites, the biology of most species of flying ectoparasites and its potential impact on avian hosts is poorly known and rarely, if ever, reported. In this study we explore for the first time the factors that may affect biting midge (Diptera:

Factors determining pochard nest predation along a wetland gradient

Czech Academy of Sciences Publication Activity Database

Albrecht, Tomáš; Hořák, D.; Kreisinger, J.; Weidinger, K.; Klvaňa, P.; Michot, T. C.

2006-01-01

Roč. 70, č. 3 (2006), s. 784-791 ISSN 0022-541X Institutional research plan: CEZ:AV0Z60930519 Keywords : common pochard * artificial nests * edge effect Subject RIV: EG - Zoology Impact factor: 1.538, year: 2006 http://www.wildlifejournals.org/archive/0022-541X/70/3/pdf/i0022-541X-70-3-784.pdf

Dynamics of habitat selection in birds: adaptive response to nest predation depends on multiple factors.

Science.gov (United States)

Devries, J H; Clark, R G; Armstrong, L M

2018-05-01

According to theory, habitat selection by organisms should reflect underlying habitat-specific fitness consequences and, in birds, reproductive success has a strong impact on population growth in many species. Understanding processes affecting habitat selection also is critically important for guiding conservation initiatives. Northern pintails (Anas acuta) are migratory, temperate-nesting birds that breed in greatest concentrations in the prairies of North America and their population remains below conservation goals. Habitat loss and changing land use practices may have decoupled formerly reliable fitness cues with respect to nest habitat choices. We used data from 62 waterfowl nesting study sites across prairie Canada (1997-2009) to examine nest survival, a primary fitness metric, at multiple scales, in combination with estimates of habitat selection (i.e., nests versus random points), to test for evidence of adaptive habitat choices. We used the same habitat covariates in both analyses. Pintail nest survival varied with nest initiation date, nest habitat, pintail breeding pair density, landscape composition and annual moisture. Selection of nesting habitat reflected patterns in nest survival in some cases, indicating adaptive selection, but strength of habitat selection varied seasonally and depended on population density and landscape composition. Adaptive selection was most evident late in the breeding season, at low breeding densities and in cropland-dominated landscapes. Strikingly, at high breeding density, habitat choice appears to become maladaptive relative to nest predation. At larger spatial scales, the relative availability of habitats with low versus high nest survival, and changing land use practices, may limit the reproductive potential of pintails.

Early kit mortality and growth in farmed mink are affected by litter size rather than nest climate.

Science.gov (United States)

Schou, T M; Malmkvist, J

2017-09-01

We investigated the effects of nest box climate on early mink kit mortality and growth. We hypothesised that litters in warm nest boxes experience less hypothermia-induced mortality and higher growth rates during the 1st week of life. This study included data from 749, 1-year-old breeding dams with access to nesting materials. Kits were weighed on days 1 and 7, dead kits were collected daily from birth until day 7 after birth, and nest climate was measured continuously from days 1 to 6. We tested the influences of the following daily temperature (T) and humidity (H) parameters on the number of live-born kit deaths and kit growth: T mean, T min, T max, T var (fluctuation) and H mean. The nest microclimate experienced by the kits was buffered against the ambient climate, with higher temperatures and reduced climate fluctuation. Most (77.0%) live-born kit deaths in the 1st week occurred on days 0 and 1. Seven of 15 climate parameters on days 1 to 3 had significant effects on live-born kit mortality. However, conflicting effects among days, marginal effects and late effects indicated that climate was not the primary cause of kit mortality. Five of 30 climate parameters had significant effects on kit growth. Few and conflicting effects indicated that the climate effect on growth was negligible. One exception was that large nest temperature fluctuations on day 1 were associated with reduced deaths of live-born kit (P<0.001) and increased kit growth (P=0.003). Litter size affected kit vitality; larger total litter size at birth was associated with greater risks of kit death (P<0.001) and reduced growth (P<0.001). The number of living kits in litters had the opposite effect, as kits in large liveborn litters had a reduced risk of death (P<0.001) and those with large mean litter size on days 1 to 7 had increased growth (P=0.026). Nest box temperature had little effect on early kit survival and growth, which could be due to dams' additional maternal behaviour. Therefore, we

Vacant Nests and Other Factors Influencing Nest Site Selection of Birds of Prey Based on Case Studies in Forest Habitats in the Forest-Steppe and Steppe Zones of Eastern Ukraine

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Stanislav G. Viter

2015-12-01

Full Text Available Our study was conducted in 2003–2012 in Eastern Ukraine, in the basin of the Seversky Donets river. The total surveyed area was ca. 900 km2 of nesting habitats suitable for raptors. A total of 69 vacant nests were found, i.e. 33.2 % of the total number of nests (208. Nests occupied by recipient species, i.e. the so-called ‘effective nest pool’, were 23–24, i.e. 33.3–34.7 % of the pool of available nests. Up to 25 % of all pairs of raptors depend on the availability of vacant nests of heterospecifics. Ravens (Corvus corax are the most significant donors of nests: 42.5 % of the pool of available nests is built by this species, and more than 60 % of them are occupied by recipient species. Common Buzzard (Buteo buteo comes second with 26.09 and 58.3 %, respectively. The most common recipients of nests are Hobbies (Falco subbuteo, Common Kestrel (Falco tinnunculus and Booted Eagles (Hieraaetus pennatus. The most significant factors that govern occupation of vacant nests by recipient species are: availability of nests in the marginal zone of forest plots, i.e. within 500 m from the forest edge, large distance from human settlements (>1500 m, presence of nests located on trees in the canopy storey, and mature and submature age of forest stands. For seven species considered in our research (n=227, the most important factors were position of nests, in the forest canopy layer, no logging activity within300 m of the nest, no regular human disturbance, and presence of “windows” in the canopy made by fallen trees.

Demand for Neste's City products grows strongly

International Nuclear Information System (INIS)

Anon.

1994-01-01

Finland's oil, chemicals, and gas company, Neste Corporation, is well on the road to better financial performance after a very difficult year in 1992. Among the factors contributing to this optimism are Neste's pioneering low environmental impact traffic fuels. Neste Corporation's net sales in 1993 rose 9.9 % on 1992 figures to USD 11,011 million. Investments totalled USD 681 million. Profitability also improved during 1993, and the operating margin rose by 57 %, despite the recession affecting the Finnish economy and the instability of the international market. The operational loss for the year before extraordinary items, reserves, and taxes was USD 265 million, one-third less than in 1992. Neste's strategy has been to achieve a strong position in the Baltic Rim region by becoming the quality and cost leader in oil refining, and by expanding Neste's position in its key markets. A total of 3.3 million tonnes of petroleum products were exported from Finland in 1993. Neste's most important export markets were Sweden, Germany, Poland, the Baltic countries, and the St. Petersburg region. Some 20 % of exports went to customers outside Europe. In addition to Finland, Neste has concertedly developed its service station network in Poland and the Baltic countries

Nest-site habitat of cavity-nesting birds at the San Joaquin Experimental Range

Science.gov (United States)

Kathryn L. Purcell; Jared. Verner

2008-01-01

Detailed information about the nesting habitats of birds, including those needed for successful nesting, can provide a better understanding of the ecological factors that permit coexistence of different species and may aid in conservation efforts. From 1989 through 1994, we studied the nesting habitat of secondary cavity-nesting birds in oak woodlands at the San...

Determinants of abundance and effects of blood-sucking flying insects in the nest of a hole-nesting bird.

Science.gov (United States)

Tomás, Gustavo; Merino, Santiago; Martínez-de la Puente, Josué; Moreno, Juan; Morales, Judith; Lobato, Elisa

2008-05-01

Compared to non-flying nest-dwelling ectoparasites, the biology of most species of flying ectoparasites and its potential impact on avian hosts is poorly known and rarely, if ever, reported. In this study we explore for the first time the factors that may affect biting midge (Diptera: Ceratopogonidae) and black fly (Diptera: Simuliidae) abundances in the nest cavity of a bird, the hole-nesting blue tit Cyanistes caeruleus, and report their effects on adults and nestlings during reproduction. The abundance of biting midges was positively associated with nest mass, parental provisioning effort and abundance of blowflies and black flies, while negatively associated with nestling condition. Furthermore, a medication treatment to reduce blood parasitaemias in adult birds revealed that biting midges were more abundant in nests of females whose blood parasitaemias were experimentally reduced. This finding would be in accordance with these insect vectors attacking preferentially uninfected or less infected hosts to increase their own survival. The abundance of black flies in the population was lower than that of biting midges and increased in nests with later hatching dates. No significant effect of black fly abundance on adult or nestling condition was detected. Blood-sucking flying insects may impose specific, particular selection pressures on their hosts and more research is needed to better understand these host-parasite associations.

Factors affecting fledgling output of great tits, Parus major, in the long term

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Rodríguez, S

2016-06-01

Full Text Available Fledgling production has often been used as an estimator of avian reproductive success, and it is conditioned by factors affecting offspring development and/or survival during the nesting period. We aimed to determine which predictors influenced fledgling output among a set of basic breeding parameters and local temperature data collected over 25 years in a Mediterranean great tit, Parus major, population, using an information–theoretic approach for model selection. Of the studied variables, the number of hatchlings per nest was the single–most important predictor influencing fledgling production, with larger broods eventually yielding more fledglings, although mass prior to fledging may have been compromised. This result suggests an overall good adjustment between brood size and resource availability in the studied population.

Factors affecting fledgling output of great tits, Parus major, in the long term

Energy Technology Data Exchange (ETDEWEB)

Rodriguez, S.; Alvarez, E.; Barba, E.

2016-07-01

Fledgling production has often been used as an estimator of avian reproductive success, and it is conditioned by factors affecting offspring development and/or survival during the nesting period. We aimed to determine which predictors influenced fledgling output among a set of basic breeding parameters and local temperature data collected over 25 years in a Mediterranean great tit, Parus major, population, using an information–theoretic approach for model selection. Of the studied variables, the number of hatchlings per nest was the single–most important predictor influencing fledgling production, with larger broods eventually yielding more fledglings, although mass prior to fledging may have been compromised. This result suggests an overall good adjustment between brood size and resource availability in the studied population. (Author)

Nest use is influenced by the positions of nests and drinkers in aviaries.

Science.gov (United States)

Lentfer, T L; Gebhardt-Henrich, S G; Fröhlich, E K F; von Borell, E

2013-06-01

The influence of the nest location and the placement of nipple drinkers on nest use by laying hens in a commercial aviary was assessed. Twenty pens in a laying hen house were equipped with the same commercial aviary system, but the pens differed in the nest location and the placement of nipple drinkers. Nests were placed along the walls in 10 pens, and nipple drinkers were installed in front of the nests in 5 of these pens. The other 10 pens were equipped with nests placed on a tier within the aviary (integrated nests). Nipple drinkers were installed in front of the nests in 5 of these pens. A total of 225 Lohmann Selected Leghorns were housed per pen. The hens were offered 4 nests per pen: 2 facing the service corridor of the laying hen house and 2 facing the outdoor area. The numbers of nest eggs and mislaid eggs were counted daily per pen. At 25, 36, and 43 wk of age, the nest platforms were videotaped and the behavior of laying hens in front of the nests was analyzed. The nest location affected the stationary and locomotive behaviors in front of the nests. Hens in front of the integrated nests and the nests with drinkers displayed more stationary behaviors than hens in front of wall-placed nests or nests without drinkers. No difference in the number of nest eggs could be detected, but the integration of the nests inside the aviary led to a more even distribution of hens while nest searching. In the pens with wall-placed nests, significantly more hens laid eggs in the nests at the wall near the service corridor than at the wall near the outdoor area. Due to this imbalance, crowding in front of the preferred nests occurred and pushing and agonistic interactions on the nest platforms were significantly more frequent. Placement of nipple drinkers in front of nests had no effect on the number of eggs laid in those nests.

Early kit mortality and growth in farmed mink are affected by litter size rather than nest climate

DEFF Research Database (Denmark)

Schou, Toke Munk; Malmkvist, Jens

2017-01-01

increased growth (P=0.026). Nest box temperature had little effect on early kit survival and growth, which could be due to dams’ additional maternal behaviour. Therefore, we cannot confirm that temperature is the primary reason for kit mortality, under the conditions of plenty straw access for maternal nest......We investigated the effects of nest box climate on early mink kit mortality and growth. We hypothesised that litters in warm nest boxes experience less hypothermia-induced mortality and higher growth rates during the 1st week of life. This study included data from 749, 1-year-old breeding dams...... building. Instead, prenatal and/or parturient litter size is the primary factor influencing early kit vitality. The results indicate that the focus should be on litter size and dam welfare around the times of gestation and birth to increase early kit survival in farmed mink....

Predation on simulated duck nests in relation to nest density and landscape structure

Czech Academy of Sciences Publication Activity Database

Padyšáková, E.; Šálek, Martin; Poledník, L.; Sedláček, František; Albrecht, Tomáš

2010-01-01

Roč. 37, č. 7 (2010), s. 597-603 ISSN 1035-3712 R&D Projects: GA MŠk LC06073 Institutional research plan: CEZ:AV0Z60870520; CEZ:AV0Z60930519 Keywords : density-dependent predation * littoral patch * landscape type * nest predators * nest success * simulated nests Subject RIV: EG - Zoology Impact factor: 1.205, year: 2010

Why wasp foundresses change nests: relatedness, dominance, and nest quality.

Directory of Open Access Journals (Sweden)

Perttu Seppä

Full Text Available The costs and benefits of different social options are best understood when individuals can be followed as they make different choices, something that can be difficult in social insects. In this detailed study, we follow overwintered females of the social wasp Polistes carolina through different nesting strategies in a stratified habitat where nest site quality varies with proximity to a foraging area, and genetic relatedness among females is known. Females may initiate nests, join nests temporarily or permanently, or abandon nests. Females can become helpers or egglayers, effectively workers or queens. What they actually do can be predicted by a combination of ecological and relatedness factors. Advantages through increased lifetime success of individuals and nests drives foundresses of the social wasp Polistes from solitary to social nest founding. We studied reproductive options of spring foundresses of P. carolina by monitoring individually-marked wasps and assessing reproductive success of each foundress by using DNA microsatellites. We examined what behavioral decisions foundresses make after relaxing a strong ecological constraint, shortage of nesting sites. We also look at the reproductive consequences of different behaviors. As in other Polistes, the most successful strategy for a foundress was to initiate a nest as early as possible and then accept others as subordinates. A common feature for many P. carolina foundresses was, however, that they reassessed their reproductive options by actively monitoring other nests at the field site and sometimes moving permanently to new nests should that offer better (inclusive fitness prospects compared to their original nests. A clear motivation for moving to new nests was high genetic relatedness; by the end of the foundress period all females were on nests with full sisters.

Why Wasp Foundresses Change Nests: Relatedness, Dominance, and Nest Quality

Science.gov (United States)

Seppä, Perttu; Queller, David C.; Strassmann, Joan E.

2012-01-01

The costs and benefits of different social options are best understood when individuals can be followed as they make different choices, something that can be difficult in social insects. In this detailed study, we follow overwintered females of the social wasp Polistes carolina through different nesting strategies in a stratified habitat where nest site quality varies with proximity to a foraging area, and genetic relatedness among females is known. Females may initiate nests, join nests temporarily or permanently, or abandon nests. Females can become helpers or egglayers, effectively workers or queens. What they actually do can be predicted by a combination of ecological and relatedness factors. Advantages through increased lifetime success of individuals and nests drives foundresses of the social wasp Polistes from solitary to social nest founding. We studied reproductive options of spring foundresses of P. carolina by monitoring individually-marked wasps and assessing reproductive success of each foundress by using DNA microsatellites. We examined what behavioral decisions foundresses make after relaxing a strong ecological constraint, shortage of nesting sites. We also look at the reproductive consequences of different behaviors. As in other Polistes, the most successful strategy for a foundress was to initiate a nest as early as possible and then accept others as subordinates. A common feature for many P. carolina foundresses was, however, that they reassessed their reproductive options by actively monitoring other nests at the field site and sometimes moving permanently to new nests should that offer better (inclusive) fitness prospects compared to their original nests. A clear motivation for moving to new nests was high genetic relatedness; by the end of the foundress period all females were on nests with full sisters. PMID:23049791

Fragmentation of nest and foraging habitat affects time budgets of solitary bees, their fitness and pollination services, depending on traits: Results from an individual-based model

Science.gov (United States)

Settele, Josef; Dormann, Carsten F.

2018-01-01

Solitary bees are important but declining wild pollinators. During daily foraging in agricultural landscapes, they encounter a mosaic of patches with nest and foraging habitat and unsuitable matrix. It is insufficiently clear how spatial allocation of nesting and foraging resources and foraging traits of bees affect their daily foraging performance. We investigated potential brood cell construction (as proxy of fitness), number of visited flowers, foraging habitat visitation and foraging distance (pollination proxies) with the model SOLBEE (simulating pollen transport by solitary bees, tested and validated in an earlier study), for landscapes varying in landscape fragmentation and spatial allocation of nesting and foraging resources. Simulated bees varied in body size and nesting preference. We aimed to understand effects of landscape fragmentation and bee traits on bee fitness and the pollination services bees provide, as well as interactions between them, and the general consequences it has to our understanding of the system. This broad scope gives multiple key results. 1) Body size determines fitness more than landscape fragmentation, with large bees building fewer brood cells. High pollen requirements for large bees and the related high time budgets for visiting many flowers may not compensate for faster flight speeds and short handling times on flowers, giving them overall a disadvantage compared to small bees. 2) Nest preference does affect distribution of bees over the landscape, with cavity-nesting bees being restricted to nesting along field edges, which inevitably leads to performance reductions. Fragmentation mitigates this for cavity-nesting bees through increased edge habitat. 3) Landscape fragmentation alone had a relatively small effect on all responses. Instead, the local ratio of nest to foraging habitat affected bee fitness positively through reduced local competition. The spatial coverage of pollination increases steeply in response to this ratio

Fragmentation of nest and foraging habitat affects time budgets of solitary bees, their fitness and pollination services, depending on traits: Results from an individual-based model.

Science.gov (United States)

Everaars, Jeroen; Settele, Josef; Dormann, Carsten F

2018-01-01

Solitary bees are important but declining wild pollinators. During daily foraging in agricultural landscapes, they encounter a mosaic of patches with nest and foraging habitat and unsuitable matrix. It is insufficiently clear how spatial allocation of nesting and foraging resources and foraging traits of bees affect their daily foraging performance. We investigated potential brood cell construction (as proxy of fitness), number of visited flowers, foraging habitat visitation and foraging distance (pollination proxies) with the model SOLBEE (simulating pollen transport by solitary bees, tested and validated in an earlier study), for landscapes varying in landscape fragmentation and spatial allocation of nesting and foraging resources. Simulated bees varied in body size and nesting preference. We aimed to understand effects of landscape fragmentation and bee traits on bee fitness and the pollination services bees provide, as well as interactions between them, and the general consequences it has to our understanding of the system. This broad scope gives multiple key results. 1) Body size determines fitness more than landscape fragmentation, with large bees building fewer brood cells. High pollen requirements for large bees and the related high time budgets for visiting many flowers may not compensate for faster flight speeds and short handling times on flowers, giving them overall a disadvantage compared to small bees. 2) Nest preference does affect distribution of bees over the landscape, with cavity-nesting bees being restricted to nesting along field edges, which inevitably leads to performance reductions. Fragmentation mitigates this for cavity-nesting bees through increased edge habitat. 3) Landscape fragmentation alone had a relatively small effect on all responses. Instead, the local ratio of nest to foraging habitat affected bee fitness positively through reduced local competition. The spatial coverage of pollination increases steeply in response to this ratio

Fragmentation of nest and foraging habitat affects time budgets of solitary bees, their fitness and pollination services, depending on traits: Results from an individual-based model.

Directory of Open Access Journals (Sweden)

Jeroen Everaars

Full Text Available Solitary bees are important but declining wild pollinators. During daily foraging in agricultural landscapes, they encounter a mosaic of patches with nest and foraging habitat and unsuitable matrix. It is insufficiently clear how spatial allocation of nesting and foraging resources and foraging traits of bees affect their daily foraging performance. We investigated potential brood cell construction (as proxy of fitness, number of visited flowers, foraging habitat visitation and foraging distance (pollination proxies with the model SOLBEE (simulating pollen transport by solitary bees, tested and validated in an earlier study, for landscapes varying in landscape fragmentation and spatial allocation of nesting and foraging resources. Simulated bees varied in body size and nesting preference. We aimed to understand effects of landscape fragmentation and bee traits on bee fitness and the pollination services bees provide, as well as interactions between them, and the general consequences it has to our understanding of the system. This broad scope gives multiple key results. 1 Body size determines fitness more than landscape fragmentation, with large bees building fewer brood cells. High pollen requirements for large bees and the related high time budgets for visiting many flowers may not compensate for faster flight speeds and short handling times on flowers, giving them overall a disadvantage compared to small bees. 2 Nest preference does affect distribution of bees over the landscape, with cavity-nesting bees being restricted to nesting along field edges, which inevitably leads to performance reductions. Fragmentation mitigates this for cavity-nesting bees through increased edge habitat. 3 Landscape fragmentation alone had a relatively small effect on all responses. Instead, the local ratio of nest to foraging habitat affected bee fitness positively through reduced local competition. The spatial coverage of pollination increases steeply in response

Landscape and regional context differentially affect nest parasitism and nest predation for Wood Thrush in central Virginia, USA (Presentation)

Science.gov (United States)

Many empirical studies have shown that forest-breeding songbirds suffer greater rates of nest predation and nest parasitism in smaller forest patches and in fragmented landscapes. To compare the performance of different metrics of spatial habitat configuration resulting from defo...

Chemical properties of forest soils as affected by nests of .i.Myrmica ruginodis./i. (Formicidae)

Czech Academy of Sciences Publication Activity Database

Véle, A.; Frouz, Jan; Holuša, J.; Kalčík, Jiří

2010-01-01

Roč. 65, č. 1 (2010), s. 122-127 ISSN 0006-3088 R&D Projects: GA MZe(CZ) QH81136 Institutional research plan: CEZ:AV0Z60660521 Keywords : ant nests * Myrmica * soil chemical properties Subject RIV: EH - Ecology, Behaviour Impact factor: 0.609, year: 2010

Nesting success and within-season breeding dispersal in the ...

African Journals Online (AJOL)

Nest predation is a primary cause of nesting mortality for many bird species, particularly passerines. Nest location can affect predation, and it has also been demonstrated that predation risk can alter nest site selection. Birds can limit predation risk by selecting specific habitat characteristics; by changing nest site ...

Ground-nesting by the chimpanzees of the Nimba Mountains, Guinea: environmentally or socially determined?

Science.gov (United States)

Koops, Kathelijne; Humle, Tatyana; Sterck, Elisabeth H M; Matsuzawa, Tetsuro

2007-04-01

The chimpanzees (Pan troglodytes verus) of the Nimba Mountains, Guinea, West Africa, commonly make both elaborate ("night") and simple ("day") nests on the ground. In this study we investigated which factors might influence ground-nesting in this population, and tested two ecological hypotheses: 1) climatic conditions, such as high wind speeds at high altitudes, may deter chimpanzees from nesting in trees; and 2) a lack of appropriate arboreal nesting opportunities may drive the chimpanzees to nest on the ground. In addition to testing these two hypotheses, we explored whether ground-nesting is a sex-linked behavior. Data were collected monthly between August 2003 and May 2004 along transects and ad libitum. To identify the sex of ground-nesting individuals, we used DNA extracted from hair samples. The results showed that the occurrence and distribution of ground nests were not affected by climatic conditions or a lack of appropriate nest trees. Support was found for the notion that ground-nesting is a sex-linked behavior, as males were responsible for building all of the elaborate ground nests and most of the simple ground nests sampled. Elaborate ground nests occurred mostly in nest groups associated with tree nests, whereas simple ground nests usually occurred without tree nests in their vicinity. These results suggest that ground-nesting may be socially, rather than ecologically, determined.

A nested case-control approach to interactions between radiation dose and other factors as causes of cancer

Energy Technology Data Exchange (ETDEWEB)

Land, Charles E [Department of Epidemiology, Radiation Epidemiology Branch, US National Cancer Institute, Bethesda, MD (United States)

1992-04-01

Often a nested case-control study is the most practicable approach to estimating the interaction of two cancer risk factors in a large cohort. If one of the factors has already been evaluated for the entire cohort, however, more information is already available about its relationship to risk than could be obtained from a nested study. A modified case-control approach is proposed, in which information about the second, unknown factor is sought for cases and controls matched on the first factor. The approach requires, for interaction models other than the multiplicative, a nonstandard analytical approach incorporating cohort-based information about the first factor. The problem is discussed in the context of breast cancer risk in a defined cohort of female Japanese atomic bomb survivors, in relation to radiation dose and reproductive history. (author)

Nesting Activity of Loggerhead Turtles (Caretta caretta at Göksu Delta, Turkey during 2004 and 2008 nesting seasons

Directory of Open Access Journals (Sweden)

Salih H. Durmus

2011-07-01

Full Text Available Göksu Delta is one of the most important nesting beaches in Turkey for the endangered loggerhead turtle (Caretta caretta. This paper provides information on the nesting activities of loggerhead turtles, the spatial and temporal distribution of nesting, nesting success, nesting density, hatching success, incubation duration and clutch size over two nesting seasons. A total of 902 emergences occurred over two seasons, of which 239 (26.5% nests were deposited (137 nests in 2004 and 102 nests in 2008 and the overall mean nesting density was 3.4 nests/km. The peak of nesting emergences takes place mainly in June. Of the overall nests, 226 (94.6% were excavated and 16044 eggs were counted. Of these eggs, 3680 (22.9% hatchlings emerged and 2695 (73.2% of hatchlings of them were able to reach the sea. The mean number of eggs per clutch was 71 (range: 15 – 143. The shortest and longest incubation duration in these 2 seasons ranged from 46 to 62 days with a mean of 53 days. The main problems are negatively affecting loggerhead turtle population at Göksu Delta are dense jackal predation both adult and eggs and inundation in nests. The average nesting effort here (mean: 119.5 nests/season confirms that Göksu Delta is one of the most important nesting sites for loggerhead turtles in Turkey.

Linking snake behavior to nest predation in a Midwestern bird community.

Science.gov (United States)

Weatherhead, Patrick J; Carfagno, Gerardo L F; Sperry, Jinelle H; Brawn, Jeffrey D; Robinson, Scott K

2010-01-01

Nest predators can adversely affect the viability of songbird populations, and their impact is exacerbated in fragmented habitats. Despite substantial research on this predator-prey interaction, however, almost all of the focus has been on the birds rather than their nest predators, thereby limiting our understanding of the factors that bring predators and nests into contact. We used radiotelemetry to document the activity of two snake species (rat snakes, Elaphe obsoleta; racers, Coluber constrictor) known to prey on nests in Midwestern bird communities and simultaneously monitored 300 songbird nests and tested the hypothesis that predation risk should increase for nests when snakes were more active and in edge habitat preferred by both snake species. Predation risk increased when rat snakes were more active, for all nests combined and for two of the six bird species for which we had sufficient nests to allow separate analyses. This result is consistent with rat snakes being more important nest predators than racers. We found no evidence, however, that nests closer to forest edges were at greater risk. These results are generally consistent with the one previous study that investigated rat snakes and nest predation simultaneously. The seemingly paradoxical failure to find higher predation risk in the snakes' preferred habitat (i.e., edge) might be explained by the snakes using edges at least in part for non-foraging activities. We propose that higher nest predation in fragmented habitats (at least that attributable to snakes) results indirectly from edges promoting larger snake populations, rather than from edges directly increasing the risk of nest predation by snakes. If so, the notion of edges per se functioning as ecological "traps" merits further study.

Common cuckoos Cuculus canorus change their nest-searching strategy according to the number of available host nests

Czech Academy of Sciences Publication Activity Database

Jelínek, Václav; Procházka, Petr; Požgayová, Milica; Honza, Marcel

2014-01-01

Roč. 156, č. 1 (2014), s. 189-197 ISSN 0019-1019 R&D Projects: GA AV ČR IAA600930605; GA AV ČR IAA600930903 Institutional support: RVO:68081766 Keywords : brood parasitism * cuckoo perch * edge effect host aggression * host choice * nest height * nest visibility * nest volume Subject RIV: EG - Zoology Impact factor: 1.921, year: 2014

Jordan Isomorphisms on Nest Subalgebras

Directory of Open Access Journals (Sweden)

Aili Yang

2015-01-01

Full Text Available This paper is devoted to the study of Jordan isomorphisms on nest subalgebras of factor von Neumann algebras. It is shown that every Jordan isomorphism ϕ between the two nest subalgebras algMβ and algMγ is either an isomorphism or an anti-isomorphism.

Spawning chronology, nest site selection and nest success of smallmouth bass during benign streamflow conditions

Science.gov (United States)

Dauwalter, D.C.; Fisher, W.L.

2007-01-01

We documented the nesting chronology, nest site selection and nest success of smallmouth bass Micropterus dolomieu in an upstream (4th order) and downstream (5th order) reach of Baron Fork Creek, Oklahoma. Males started nesting in mid-Apr. when water temperatures increased to 16.9 C upstream, and in late-Apr. when temperatures increased to 16.2 C downstream. Streamflows were low (77% upstream to 82% downstream of mean Apr. streamflow, and 12 and 18% of meanjun. streamflow; 47 and 55 y of record), and decreased throughout the spawning period. Larger males nested first upstream, as has been observed in other populations, but not downstream. Upstream, progeny in 62 of 153 nests developed to swim-up stage. Downstream, progeny in 31 of 73 nests developed to swim-up. Nesting densities upstream (147/km) and downstream (100/km) were both higher than any densities previously reported. Males selected nest sites with intermediate water depths, low water velocity and near cover, behavior that is typical of smallmouth bass. Documented nest failures resulted from human disturbance, angling, and longear sunfish predation. Logistic exposure models showed that water velocity at the nest was negatively related and length of the guarding male was positively related to nest success upstream. Male length and number of degree days were both positively related to nest success downstream. Our results, and those of other studies, suggest that biological factors account for most nest failures during benign (stable, low flow) streamflow conditions, whereas nest failures attributed to substrate mobility or nest abandonment dominate when harsh streamflow conditions (spring floods) coincide with the spawning season.

Neste Corporation - a successful year

International Nuclear Information System (INIS)

Ihamuotila, J.

1991-01-01

The past year proved a successful one for Neste Corporation. Profitability was good and operations were consistently developed. Neste is committed to giving high priority to productivity and know- how to ensure that this success continues into the future. Important developments affecting the structure of Neste Corporation during 1990 included the amalgamation of Neste's oil-related activities into a single division, the increasing concentration of Neste Chemicals, activities in Central and Southern Europe and a major strengthening of oil exploration and production operations. Neste Oil turned in a good result during 1990. Neste imported a total of 8.9 million tonnes of crude oil during 1990. Imports from the Soviet Union at 5.2 million tonnes, were over 2 million tonnes less than planned. Some 2.5 million tonnes were imported from the North Sea, and 1.2 million tonnes from the Middle East. The year was one of expansion, diversification, and solid profit for Neste Chemicals. Net sales grew by 18 % compared to 1989 and the division recorded a satisfactory performance. Petrochemicals and polyolefins production increased suhstantially as a result of plants completed, acquired, or leased during 1989. The gas division's net sales during 1990 were 46 % higher than during 1989. This growth largely resulted from an increase in the consumption of natural gas and an expansion in the volume of international IPG business. The division's profitability remained satisfactory

Off-road vehicles affect nesting behaviour and reproductive success of American Oystercatchers Haematopus palliatus

Science.gov (United States)

Borneman, Tracy E.; Rose, Eli T.; Simons, Theodore R.

2016-01-01

As human populations and associated development increase, interactions between humans and wildlife are occurring with greater frequency. The effects of these interactions, particularly on species whose populations are declining, are of great interest to ecologists, conservationists, land managers and natural resource policy-makers. The American Oystercatcher Haematopus palliatus, a species of conservation concern in the USA, nests on coastal beaches subject to various forms of anthropogenic disturbance, including aircraft overflights, off-road vehicles and pedestrians. This study assessed the effects of these human disturbances on the incubation behaviour and reproductive success of nesting American Oystercatchers at Cape Lookout National Seashore, on the Atlantic coast of the USA. We expanded on-going monitoring of Oystercatchers at Cape Lookout National Seashore by supplementing periodic visual observations with continuous 24-h video and audio recording at nests. Aircraft overflights were not associated with changes in Oystercatcher incubation behaviour, and we found no evidence that aircraft overflights influenced Oystercatcher reproductive success. However, Oystercatchers were on their nests significantly less often during off-road vehicle and pedestrian events than they were during control periods before the events, and an increase in the number of off-road vehicles passing a nest during incubation was consistently associated with significant reductions in daily nest survival (6% decrease in daily nest survival for a one-vehicle increase in the average number of vehicles passing a nest each day; odds ratio = 0.94; 95% confidence interval (CI) 0.90, 0.98) and hatching success (12% decrease in hatching success for a one-vehicle increase in the average number of vehicles passing a nest each day; odds ratio = 0.88; 95% CI 0.76, 0.97). Management of vehicles and pedestrians in areas of Oystercatcher breeding is important for the conservation of American

Precision of Nest Method in Estimating Orangutan Population and Determination of Important Ecological Factors for Management of Conservation Forest

Directory of Open Access Journals (Sweden)

Yanto Santosa

2012-04-01

Full Text Available Orangutan as an umbrella species is closely interlinked with sustainable forest management meaning that the protection of this species has implications on the protection of other species and maintain ecosystem stability.  The total natural habitat required to support orangutan’s population could only be determined by the appropriate population size. It is associated with the carrying capacity to accommodate or fulfill the habitat requirements of a wildlife population. Selection and delineation of core and wilderness zones as habitat preference should be based on the results of preference test shown by the spatial distribution of orangutan population. Value of the coefficient  of  variation (CV was used to observe the precision of the population estimation and to identify important ecological factors in selection of nesting trees.  The study resulted in varied CV spatial values for various habitat types: 22.60%,  11.20%, and 13.30% for heath, lowland dipterocarp, and peat swamp forest, respectively. In the other side, CV temporal values for various habitat types were 5.35%, 22.60%, and 17.60% for heath, lowland dipterocarp, and peat swamp forest, respectively. This indicated that the population density in each type of forest ecosystems had a variation based on location and did not varied according to time of survey.  The use of  nest survey technique showed good reliable results in estimating orangutan population density.  Efforts to improve the precision of estimation can be done by formulating r value as the harmonic average of nest production rates and t as the average of nest decay time per nest category. Selection of habitat preference and nest trees were influenced by food availability thus should form important consideration in conducting nest survey to avoid bias in estimating orangutan populations.Keywords: conservation forest management, nest survey, orangutan, population size, ecological factors

Do nest light conditions affect rejection of parasitic eggs? A test of the light environment hypothesis

Czech Academy of Sciences Publication Activity Database

Honza, Marcel; Procházka, Petr; Morongová, Klára; Čapek, Miroslav; Jelínek, Václav

2011-01-01

Roč. 117, č. 6 (2011), s. 539-546 ISSN 0179-1613 R&D Projects: GA AV ČR IAA600930903; GA MŠk LC06073 Institutional research plan: CEZ:AV0Z60930519 Keywords : Acrocephalus arundinaceus * nest light conditions * egg recognition * Great reed warbler * cuckoo Subject RIV: EG - Zoology Impact factor: 2.008, year: 2011

Effect of nest design, passages, and hybrid on use of nest and production performance of layers in furnished cages.

Science.gov (United States)

Wall, H; Tauson, R; Elwinger, K

2002-03-01

Production performance, including egg quality, and proportion of eggs laid in nests were studied in furnished experimental cages incorporating nests, litter baths, and perches. The study comprised a total of 972 hens of two genotypes: Lohmann Selected Leghorn (LSL) and Hy-Line White. The birds were studied from 20 to 80 wk of age, and conventional four-hen cages were included as a reference. In furnished cages for six hens, the effects of 30 or 50% vs. 100% nest bottom lining (Astro turf) were studied with LSL hens. Nest bottom lining had no significant effect on egg production or proportions of cracked or dirty eggs, but the use of nests was significantly higher in cages incorporating nests with 100% lining, compared with 50 or 30%. The two hybrids were compared when housed in large, group-furnished cages for 14 or 16 hens of two designs; with a rear partition with two pop holes or fully open, i.e., no rear partition. LSL birds produced significantly better and had a significantly lower proportion of cracked eggs. There was no difference between H- and O-cages, either in production or in egg quality. LSL birds laid a significantly lower proportion of eggs in the nests, especially in O-cages, implying a significant hybrid x cage interaction. When housed in conventional cages, the hybrids did not differ in proportion of cracked eggs but differed in production traits. It was concluded that with the present nest design, the proportion of nest bottom lining cannot be reduced without affecting birds' use of nests, but the proportion did not affect exterior egg quality. The effect of genotype should be considered in the further development of furnished cages.

Small-scale area effect on species richness and nesting occupancy of cavity-nesting bees and wasps

Directory of Open Access Journals (Sweden)

Rafael D. Loyola

2011-03-01

Full Text Available Small-scale area effect on species richness and nesting occupancy of cavity-nesting bees and wasps. The research was conducted in an urban forest remnant in southeast Brazil. We tested the predictions of the following hypotheses: (1 larger areas present higher species richness of bees and wasps, (2 solitary bees and wasps occupy more nests in larger areas, (3 rare species occupy more nests in smaller areas. We sampled Aculeate bees and wasps using trap nests from February to November 2004. We placed trap nests in sampling units (SU with different size (25, 100 and 400 m² located in 6 ha of secondary mesophytic forest. One hundred and thirty-seven trap nests were occupied by seven species of bees and four species of wasps. We found an increase in wasp, but not bee species richness following increase in SU size. Hymenoptera richness (i.e. bees plus wasps was also greater in larger SU. Both the number and density of occupied nests increased with SU size. The wasp Trypoxylon lactitarse responded significantly to area size, larger SU having more occupied nests. The same pattern was exhibited by the wasp Auplopus militaris, the Megachile bee species, and the bee Anthodioctes megachiloides. Only Trypoxylon sp. was not affected by SU size. Our results show that cavity-nesting bee and wasps respond differently to the area effects. Such findings must be complemented by information on the frequency and dynamics of area colonization and nest occupancy by species of solitary Hymenoptera.

Nest sharing under semi-natural conditions in laying hens

DEFF Research Database (Denmark)

Riber, Anja Brinch

2012-01-01

problems to laying hens, and egg production may also be negatively affected. Understanding what causes this difference in nest location selection may provide solutions to the problems associated with simultaneous nest sharing. The aims were to investigate whether a commercial strain of laying hens normally...... daily of each nest with regard to number of eggs, position, and materials used. On five mornings nesting behaviour was observed. Nest sharing occurred on all but the first 5 days of egg-laying. The majority of hens (n = 14) chose to visit an occupied nest at least once, but no hens exclusively used...

Buteo Nesting Ecology: Evaluating Nesting of Swainson's Hawks in the Northern Great Plains.

Science.gov (United States)

Inselman, Will M; Datta, Shubham; Jenks, Jonathan A; Jensen, Kent C; Grovenburg, Troy W

2015-01-01

Swainson's hawks (Buteo swainsoni) are long-distance migratory raptors that nest primarily in isolated trees located in areas of high grassland density. In recent years, anthropogenic conversion of grassland habitat has raised concerns about the status of the breeding population in the northern Great Plains. In 2013, we initiated a study to investigate the influence of extrinsic factors influencing Swainson's hawk nesting ecology in north-central South Dakota and south-central North Dakota. Using ground and aerial surveys, we located and monitored nesting Swainson's hawk pairs: 73 in 2013 and 120 in 2014. We documented 98 successful breeding attempts that fledged 163 chicks; 1.52 and 1.72 fledglings per successful nest in 2013 and 2014, respectively. We used Program MARK to evaluate the influence of land cover on nest survival. The top model, SDist2Farm+%Hay, indicated that nest survival (fledging at least one chick) decreased as nests were located farther from farm sites and as the percent of hay cover increased within 1200-m of the nest site (34.4%; 95% CI = 27.6%-42.3%). We used logistic regression analysis to evaluate the influence of landscape variables on nest-site selection; Swainson's hawks selected for nest sites located closer to roads. We suggest that tree belts associated with farm sites, whether occupied or not, provide critical breeding sites for Swainson's hawks. Additionally, poor breeding success may be related to the late migratory behavior of this species which requires them to occupy marginal habitat due to other raptors occupying the most suitable habitat prior to Swainson's hawks arriving to the breeding grounds.

The importance of illumination in nest site choice and nest characteristics of cavity nesting birds.

Science.gov (United States)

Podkowa, Paweł; Surmacki, Adrian

2017-05-02

Light has a significant impact on many aspects of avian biology, physiology and behaviour. An increasing number of studies show that illumination may positively influences birds' offspring fitness by e.g. acceleration of embryo development, stimulation of skeleton growth or regulation of circadian rhythm. Because nest cavities have especially low illumination, suitable light levels may be especially important for species which nest there. We may therefore expect that birds breeding in relatively dim conditions should prefer brighter nest sites and/or evolve behavioral mechanisms to secure sufficient light levels in the nest. Using nest boxes with modified internal illumination, we experimentally tested whether light regime is a cue for nest site selection of secondary cavity-nesting species. Additionally, we investigated whether nest building strategies are tuned to internal illumination. Our results demonstrate that, nest boxes with elevated illumination were chosen twice as often as dark nest boxes. Moreover, birds built higher nests in dark nest boxes than birds in boxes with elevated illumination, which suggests a mechanism of compensating for low light conditions. Our results provide the first experimental support for the idea that nest site choice and nest building behaviour in cavity-nesting birds are influenced by ambient illumination.

Evolution of sexual dichromatism in relation to nesting habits in European passerines: a test of Wallace's hypothesis.

Science.gov (United States)

Soler, J J; Moreno, J

2012-08-01

Wallace proposed in 1868 that natural rather than sexual selection could explain the striking differences in avian plumage dichromatism. Thus, he predicted that nesting habits, through their association with nest predation, could drive changes in sexual dichromatism by enabling females in cavity nesters to become as conspicuous as males, whereas Darwin (1871, The Descent of Man and Selection in Relation to Sex, John Murray, London) argued that sexual selection was the sole explanation for dichromatism. Sexual dichromatism is currently used as indicating the strength of sexual selection, and therefore testing Wallace's claim with modern phylogentically controlled methodologies is of prime interest for comparing the roles of natural and sexual selection in affecting the evolution of avian coloration. Here, we have related information on nest attendance, sexual dichromatism and nesting habits (open and cavity nesting) to male and female plumage conspicuousness in European passerines. Nest incubation attendance does not explain male or female plumage conspicuousness but nest type does. Moreover, although females of monochromatic and cavity nesting species are more conspicuous than females of other species, males of monochromatic and open nesting species are those with more cryptic plumage. Finally, analyses of character evolution suggest that changes in nesting habits influence the probability of changes in both dichromatism and plumage conspicuousness of males but do not significantly affect those in females. These results strongly suggest a role of nesting habits in the evolution of plumage conspicuousness of males, and a role for sexual selection also in females, both factors affecting the evolution of sexual dichromatism. We discuss our findings in relation to the debate that Darwin and Wallace maintained more than one century ago on the importance of natural and sexual selection in driving the evolution of plumage conspicuousness and sexual dichromatism in birds

Cavity-nesting bird abundance in thinned versus unthinned Massachusetts oak stands

Science.gov (United States)

Christopher J.E. Welsh; William M. Healy; Richard M. DeGraaf

1992-01-01

Cavity-nesting birds provide significant benefits to forest communities, but timber management techniques may negatively affect cavity-nesting species by reducing the availability of suitable nest and foraging sites. We surveyed cavity-nesting birds from transects in eight Massachusetts oak stands to examine the effect of thinning with retention of snag and wildlife...

Buteo Nesting Ecology: Evaluating Nesting of Swainson’s Hawks in the Northern Great Plains

Science.gov (United States)

Inselman, Will M.; Datta, Shubham; Jenks, Jonathan A.; Jensen, Kent C.; Grovenburg, Troy W.

2015-01-01

Swainson’s hawks (Buteo swainsoni) are long-distance migratory raptors that nest primarily in isolated trees located in areas of high grassland density. In recent years, anthropogenic conversion of grassland habitat has raised concerns about the status of the breeding population in the northern Great Plains. In 2013, we initiated a study to investigate the influence of extrinsic factors influencing Swainson’s hawk nesting ecology in north-central South Dakota and south-central North Dakota. Using ground and aerial surveys, we located and monitored nesting Swainson’s hawk pairs: 73 in 2013 and 120 in 2014. We documented 98 successful breeding attempts that fledged 163 chicks; 1.52 and 1.72 fledglings per successful nest in 2013 and 2014, respectively. We used Program MARK to evaluate the influence of land cover on nest survival. The top model, S Dist2Farm+%Hay, indicated that nest survival (fledging at least one chick) decreased as nests were located farther from farm sites and as the percent of hay cover increased within 1200-m of the nest site (34.4%; 95% CI = 27.6%–42.3%). We used logistic regression analysis to evaluate the influence of landscape variables on nest-site selection; Swainson’s hawks selected for nest sites located closer to roads. We suggest that tree belts associated with farm sites, whether occupied or not, provide critical breeding sites for Swainson’s hawks. Additionally, poor breeding success may be related to the late migratory behavior of this species which requires them to occupy marginal habitat due to other raptors occupying the most suitable habitat prior to Swainson’s hawks arriving to the breeding grounds. PMID:26327440

Tactic changes in dusky frillgoby Bathygobius fuscus sneaker males: effects of body size and nest availability.

Science.gov (United States)

Takegaki, T; Kaneko, T; Matsumoto, Y

2013-02-01

Field and laboratory studies were conducted to examine the effects of nest availability and body size on changes in male mating tactics from sneaking to nest-holding in the dusky frillgoby Bathygobius fuscus. In the field, the body size of nest-holding males decreased from early to mid-breeding season, suggesting the possibility of a change in the tactics of sneaker males to nest-holding. Many sneaker males did not use vacant spawning nests even when size-matched nests were available, but they continued to reproduce as sneakers. Similarly, in aquarium experiments with available vacant nests, some sneaker males became nest-holders irrespective of their body size, but some did not. These results showed that nest availability is not a limiting factor for changes in tactics by sneaker males in this species. Because tactic-unchanged sneaker males were co-housed with larger nest-holding males in the tanks, the body size of nearby nest-holding males may have affected the decision to change tactics for sneaker males. Moreover, smaller individuals among tactic-changed males tended to spend more time until spawning, probably because they had relatively larger costs and smaller benefits of reproduction as nest-holding males compared to larger males. © 2012 The Authors. Journal of Fish Biology © 2012 The Fisheries Society of the British Isles.

Nest design in a changing world: great tit Parus major nests from a Mediterranean city environment as a case study.

Science.gov (United States)

Lambrechts, Marcel M; Charmantier, Anne; Demeyrier, Virginie; Lucas, Annick; Perret, Samuel; Abouladzé, Matthieu; Bonnet, Michel; Canonne, Coline; Faucon, Virginie; Grosset, Stéphanie; le Prado, Gaëlle; Lidon, Frédéric; Noell, Thierry; Pagano, Pascal; Perret, Vincent; Pouplard, Stéphane; Spitaliéry, Rémy; Bernard, Cyril; Perret, Philippe; Blondel, Jacques; Grégoire, Arnaud

2017-12-01

Investigations of urbanization effects on birds have focused mainly on breeding traits expressed after the nest-building stage (e.g. first-egg date, clutch size, breeding success, and offspring characteristics). Urban studies largely ignored how and why the aspects of nest building might be associated with the degree of urbanization. As urban environments are expected to present novel environmental changes relative to rural environments, it is important to evaluate how nest-building behavior is impacted by vegetation modifications associated with urbanization. To examine nest design in a Mediterranean city environment, we allowed urban great tits ( Parus major ) to breed in nest boxes in areas that differed in local vegetation cover. We found that different measures of nest size or mass were not associated with vegetation cover. In particular, nests located adjacent to streets with lower vegetation cover were not smaller or lighter than nests in parks with higher vegetation cover. Nests adjacent to streets contained more pine needles than nests in parks. In addition, in nests adjacent to streets, nests from boxes attached to pine trees contained more pine needles than nests from boxes attached to other trees. We suggest that urban-related alterations in vegetation cover do not directly impose physical limits on nest size in species that are opportunistic in the selection of nesting material. However, nest composition as reflected in the use of pine needles was clearly affected by habitat type and the planted tree species present, which implies that rapid habitat change impacts nest composition. We do not exclude that urbanization might impact other aspects of nest building behaviour not covered in our study (e.g. costs of searching for nest material), and that the strengths of the associations between urbanization and nest structures might differ among study populations or species.

Nest site selection by Hypsiboas faber(Anura, Hylidae in Southern Brazil

Directory of Open Access Journals (Sweden)

André L. Luza

2015-12-01

Full Text Available ABSTRACT Male gladiator frogs of Hypsiboas Wagler, 1830 build nests on available substrate surrounding ponds and streams where female spawn eggs during the breeding period. Although gladiator frogs seem to show plasticity in the way they construct their nests, there is no study reporting if these species present preferences about microhabitat conditions for nest-building (mainly under subtropical climate. Predation pressure and environmental conditions have been considered major processes shaping the great diversity of reproductive strategies performed by amphibians, but microhabitat conditions should explain where to build a nest as well as how nest looks. This study aimed to test nest site selection for nest-building by Hypsiboas faber(Wied-Neuwied, 1821, determining which factors are related to nest site selection and nest features. The survey was conducted at margins of two permanent ponds in Southern Brazil. Habitat factors were evaluated in 18 plots with nest and 18 plots in the surrounding without nest (control, describing vegetation structure and heterogeneity, and substrate characteristics. Water temperature was measured inside the nest and in its adjacency. Nest features assessed were area, depth and temperature. Habitat characteristics differed between plots with and without nest. Microhabitat selected for nest-building was characterized by great vegetation cover and height, as well as shallower water and lower cover of organic matter in suspension than in plots without nest. Differences between temperature inside nest and in its adjacency were not observed. No relationship between nest features and habitat descriptors was evidenced. Results revealed that Hypsiboas faber does not build nests anywhere. Males seem to prefer more protected habitats, probably avoiding predation, invasion of conspecific males and inclement weather. Lack of differences between temperature inside- and outside-nest suggest that nest do not improve this

Effect of methodological and ecological approaches on heterogeneity of nest-site selection of a long-lived vulture.

Directory of Open Access Journals (Sweden)

Rubén Moreno-Opo

Full Text Available The application of scientific-based conservation measures requires that sampling methodologies in studies modelling similar ecological aspects produce comparable results making easier their interpretation. We aimed to show how the choice of different methodological and ecological approaches can affect conclusions in nest-site selection studies along different Palearctic meta-populations of an indicator species. First, a multivariate analysis of the variables affecting nest-site selection in a breeding colony of cinereous vulture (Aegypius monachus in central Spain was performed. Then, a meta-analysis was applied to establish how methodological and habitat-type factors determine differences and similarities in the results obtained by previous studies that have modelled the forest breeding habitat of the species. Our results revealed patterns in nesting-habitat modelling by the cinereous vulture throughout its whole range: steep and south-facing slopes, great cover of large trees and distance to human activities were generally selected. The ratio and situation of the studied plots (nests/random, the use of plots vs. polygons as sampling units and the number of years of data set determined the variability explained by the model. Moreover, a greater size of the breeding colony implied that ecological and geomorphological variables at landscape level were more influential. Additionally, human activities affected in greater proportion to colonies situated in Mediterranean forests. For the first time, a meta-analysis regarding the factors determining nest-site selection heterogeneity for a single species at broad scale was achieved. It is essential to homogenize and coordinate experimental design in modelling the selection of species' ecological requirements in order to avoid that differences in results among studies would be due to methodological heterogeneity. This would optimize best conservation and management practices for habitats and species in

Arctic foxes, lemmings, and canada goose nest survival at cape Churchill, Manitoba

Science.gov (United States)

Reiter, M.E.; Andersen, D.E.

2011-01-01

We examined factors influencing Canada Goose (Branta canadensis interior) annual nest success, including the relative abundance of collared lemmings (Dicrostonyx richardsoni), arctic fox (Alopex lagopus) den occupancy, nest density, and spring phenology using data collected during annual Canada Goose breeding area surveys at Cape Churchill, Manitoba. Nest density and arctic fox den occupancy strongly influenced Canada Goose nest success. High nest density resulted in higher nest success and high den occupancy reduced nest success. Nest success was not influenced by lemming abundance in the current or previous year as predicted by the "bird-lemming" hypothesis. Reducing arctic fox abundance through targeted management increased nest survival of Canada Geese; a result that further emphasizes the importance of arctic fox as nest predators in this system. The spatial distribution of nest predators, at least for dispersed-nesting geese, may be most important for nest survival, regardless of the abundance of small mammals in the local ecosystem. Further understanding of the factors influencing the magnitude and variance in arctic fox abundance in this region, and the spatial scale at which these factors are realized, is necessary to fully explain predator-prey-alternative prey dynamics in this system. ?? 2011 by the Wilson Ornithological Society.

Importance of structural stability to success of mourning dove nests

Science.gov (United States)

Coon, R.A.; Nichols, J.D.; Percival, H.F.

1981-01-01

Studies of nest-site selection and nesting habitats often involve a "characterization" of nests and of habitats in which nests are found. Our objective in the present work is to identify nest-site characteristics that are associated with variation in components of Mourning Dove (Zenaida macroura) fitness (e.g. the probability of a nest succeeding), as opposed to simply "characterizing" dove nest sites. If certain nest- site characteristics affect the probability that a nest will succeed, then we suspect that these characteristics will be associated with either concealment (the probability of detection by certain predators) or structural stability (the probability of eggs or entire nests falling to the ground as a result of wind, rain storms, parental activity, etc.). Although other workers agree that structural stability is an important determinant of Mourning Dove nesting success (e.g. McClure 1944: 384; Woolfenden and Rohwer 1969: 59), we are aware of no actual tests of this hypothesis.

Interspecific and intraspecific spatial separation by birds breeding in nest boxes

Directory of Open Access Journals (Sweden)

Denis C. Deeming

2017-12-01

Full Text Available Nest boxes can be seen as a conservation tool for improving low-grade nesting habitat but it is unclear how sympatric species using boxes establish a spatial distribution relative to conspecifics and heterospecifics. This study determined the distances between nest boxes occupied by Blue Tits (Cyanistes caeruleus and Great Tits (Parus major in two British woodlands to ascertain whether spatial distribution was affected by species and, if it was, whether there were reproductive consequences of this breeding distribution. Occupancy of nest boxes at two woodland sites were recorded on an annual basis between 2010 and 2014, inclusive. Distances between nest boxes, and reproductive activity, were recorded. Even if nest boxes showed a clumped distribution in the woodlands, the occupancy of the boxes was random. Not all boxes were used and the minimum distance between occupied boxes was at least twice the distance between boxes in general. Blue Tits tended to have greater distances between boxes containing conspecifics but distances between boxes containing heterospecifics were generally of comparable lengths. Reproductive output was only affected in relation to clutch size for Blue Tits nesting at one site. Nest boxes that aim to improve habitats that lack suitable nesting sites should be placed to reflect actual dispersal distances of the focal bird species.

Body size mediates social and environmental effects on nest building behaviour in a fish with paternal care.

Science.gov (United States)

Lehtonen, Topi K; Lindström, Kai; Wong, Bob B M

2015-07-01

Body size, social setting, and the physical environment can all influence reproductive behaviours, but their interactions are not well understood. Here, we investigated how male body size, male-male competition, and water turbidity influence nest-building behaviour in the sand goby (Pomatoschistus minutus), a marine fish with exclusive paternal care. We found that environmental and social factors affected the nest characteristics of small and large males differently. In particular, association between male size and the level of nest elaboration (i.e. the amount of sand piled on top of the nest) was positive only under clear water conditions. Similarly, male size and nest entrance size were positively associated only in the absence of competition. Such interactions may, in turn, help to explain the persistence of variation in reproductive behaviours, which-due to their importance in offspring survival-are otherwise expected to be under strong balancing selection.

Is it safe to nest near conspicuous neighbours? Spatial patterns in predation risk associated with the density of American Golden-Plover nests

OpenAIRE

Marie-Andrée Giroux; Myriam Trottier-Paquet; Joël Bêty; Vincent Lamarre; Nicolas Lecomte

2016-01-01

Predation is one of the main factors explaining nesting mortality in most bird species. Birds can avoid nest predation or reduce predation pressure by breeding at higher latitude, showing anti-predator behaviour, selecting nest sites protected from predators, and nesting in association with protective species. American Golden-Plovers (Pluvialis dominica) defend their territory by using various warning and distraction behaviours displayed at varying levels of intensity (hereafter ?conspicuous ...

Factors affecting attendance to cervical cancer screening among women in the Paracentral Region of El Salvador: a nested study within the CAPE HPV screening program.

Science.gov (United States)

Alfaro, Karla M; Gage, Julia C; Rosenbaum, Alan J; Ditzian, Lauren R; Maza, Mauricio; Scarinci, Isabel C; Miranda, Esmeralda; Villalta, Sofia; Felix, Juan C; Castle, Philip E; Cremer, Miriam L

2015-10-16

Cervical cancer is the third most commonly occurring cancer among women and the fourth leading cause of cancer-related deaths in women worldwide, with more than 85 % of these cases occurring in developing countries. These global disparities reflect the differences in cervical cancer screening rates between high-income and medium- and low-income countries. At 19 %, El Salvador has the lowest reported screening coverage of all Latin American countries. The purpose of this study is to identify factors affecting public sector HPV DNA-based cervical cancer screening participation in El Salvador. This study was nested within a public sector screening program where health promoters used door-to-door outreach to recruit women aged 30-49 years to attend educational sessions about HPV screening. A subgroup of these participants was chosen randomly and questioned about demographic factors, healthcare utilization, previous cervical cancer screening, and HPV knowledge. Women then scheduled screening appointments at their public health clinics. Screening participants were adherent if they attended their scheduled appointment or rescheduled and were screened within 6 months. The association between non-adherence and demographic variables, medical history, history of cancer, sexual history, birth control methods, and screening barriers was assessed using Chi-square tests of significance and logistic regression. All women (n = 409) enrolled in the study scheduled HPV screening appointments, and 88 % attended. Non-adherence was associated with a higher number of lifetime partners and being under-screened-defined as not having participated in cervical cancer screening within the previous 3 years (p = 0.03 and p = 0.04, respectively); 22.8 % of participants in this study were under-screened. Adherence to cervical cancer screening after educational sessions was higher than expected, in part due to interactions with the community-based health promoters as well as the educational session

Response of beach-nesting American Oystercatchers to off-road vehicles: An experimental approach reveals physiological nuances and decreased nest attendance

Science.gov (United States)

Felton, Shilo K.; Pollock, Kenneth H.; Simons, Theodore R.

2018-01-01

Shorebird populations face increasing challenges as rising sea levels and growing human populations constrain their breeding habitats. On recreational beaches, the nesting season often coincides with a season of high visitor use, increasing the potential for conflict, which may negatively influence beach-nesting shorebird species. We designed a field experiment to study the responses of nesting American Oystercatchers (Haematopus palliatus) to off-road passenger vehicles (ORVs) at Cape Hatteras and Cape Lookout National Seashores in North Carolina, USA. We used continuous video and heart rate recordings to assess changes in the behavior and physiology of incubating oystercatchers. We conducted driving experiments affecting 7 nesting pairs in 2014 and 19 nesting pairs in 2015, between April and July of each year. Experimental treatments were repeated throughout the incubation period for each nest. Although responses were highly variable within and among pairs, paired randomized permutation tests indicated that, overall, oystercatcher pairs spent a greater proportion of time with their heads up and exhibited slower heart rates during driving treatments. Pairs also left their nests more frequently and attended their nests for a lower proportion of time during driving treatments, although these responses diminished over time. Higher nest attendance and lower departure rates late in incubation may have reflected a stronger attachment to nests closer to hatching or habituation to the driving treatment, although individuals continued to exhibit physiological responses to passing vehicles throughout incubation. Beach-nesting birds may benefit from reduced vehicle traffic at their nesting sites, allowing parents to spend more time attending the nest and less time on defensive behaviors.

Power lines, roads, and avian nest survival: effects on predator identity and predation intensity.

Science.gov (United States)

DeGregorio, Brett A; Weatherhead, Patrick J; Sperry, Jinelle H

2014-05-01

1 Anthropogenic alteration of landscapes can affect avian nest success by influencing the abundance, distribution, and behavior of predators. Understanding avian nest predation risk necessitates understanding how landscapes affect predator distribution and behavior. 2 From a sample of 463 nests of 17 songbird species, we evaluated how landscape features (distance to forest edge, unpaved roads, and power lines) influenced daily nest survival. We also used video cameras to identify nest predators at 137 nest predation events and evaluated how landscape features influenced predator identity. Finally, we determined the abundance and distribution of several of the principal predators using surveys and radiotelemetry. 3 Distance to power lines was the best predictor of predator identity: predation by brown-headed cowbirds (Molothrus ater), corvids (Corvus sp. and Cyanocitta cristata), racers (Coluber constrictor), and coachwhips (Masticophis flagellum) increased with proximity to power lines, whereas predation by rat snakes (Elaphe obsoleta) and raptors decreased. In some cases, predator density may reliably indicate nest predation risk because racers, corvids, and cowbirds frequently used power line right-of-ways. 4 Of five bird species with enough nests to analyze individually, daily nest survival of only indigo buntings (Passerina cyanea) decreased with proximity to power lines, despite predation by most predators at our site being positively associated with power lines. For all nesting species combined, distance to unpaved road was the model that most influenced daily nest survival. This pattern is likely a consequence of rat snakes, the locally dominant nest predator (28% of predation events), rarely using power lines and associated areas. Instead, rat snakes were frequently associated with road edges, indicating that not all edges are functionally similar. 5 Our results suggest that interactions between predators and landscape features are likely to be specific to

The cavity-nest ant Temnothorax crassispinus prefers larger nests.

Science.gov (United States)

Mitrus, S

Colonies of the ant Temnothorax crassispinus inhabit mostly cavities in wood and hollow acorns. Typically in the field, nest sites that can be used by the ant are a limited resource. In a field experiment, it was investigated whether the ants prefer a specific size of nest, when different ones are available. In July 2011, a total of 160 artificial nests were placed in a beech-pine forest. Four artificial nests (pieces of wood with volume cavities, ca 415, 605, 730, and 980 mm 3 , respectively) were located on each square meter of the experimental plot. One year later, shortly before the emergence of new sexuals, the nests were collected. In July 2012, colonies inhabited more frequently bigger nests. Among queenright colonies, the ones which inhabited bigger nests had more workers. However, there was no relationship between volume of nest and number of workers for queenless colonies. Queenright colonies from bigger nests produced more sexual individuals, but there was no correlation between number of workers and sex allocation ratio, or between volume of nest and sex allocation ratio. In a laboratory experiment where ant colonies were kept in 470 and 860 mm 3 nests, larger colonies allocated more energy to produce sexual individuals. The results of this study show the selectivity of T. crassispinus ants regarding the size of nest cavity, and that the nest volume has an impact on life history parameters.

Using survival analysis of artificial and Real Brewer's sparrow (Spizella breweri breweri) nests to model site level and nest site factors associated with nest success in the South Okanagan region of Canada

Science.gov (United States)

Pam Krannitz Kym Welstead

2005-01-01

Predation is the predominant cause of nest failure for the Brewer's Sparrow (Spizella breweri breweri), a provincially red-listed shrub-steppe species that has experienced significant declines throughout most of its range. We monitored Brewer’s Sparrow nests and conducted an artificial nest experiment, in the South Okanagan Valley,...

The ART of mating: alternative reproductive tactics and mating success in a nest-guarding fish.

Science.gov (United States)

Mascolino, S; Benvenuto, C; Gubili, C; Sacchi, C; Boufana, B; Mariani, S

2016-12-01

Behavioural observations in the field of male Mediterranean damselfish Chromis chromis were combined with molecular analyses, using bi-parentally and maternally inherited markers, to investigate reproductive success patterns of alternative reproductive tactics (ARTs) in terms of number of eggs sired and number of females contributing to each nest. Cuckoldry was observed in every nest sampled, with at least two and up to seven sneaker males per nest. The nesting male, however, always significantly fertilized the greater number of eggs (on average 49%) in each clutch, whereas each sneaker fertilized around 7% of the clutch. The average number of females whose eggs were fertilized by nesting males was 6·76 (range 2-13), while each sneaker on average fertilized the eggs of 1·74 (range 1-8) females. Using this sibship reconstruction, some of the factors involved in the regulation of the dynamic equilibrium of reproductive success were investigated between the two ARTs shown by C. chromis males. Results show that the sneakers' reproductive success was positively linked to egg clutch size; the density of individuals in the nesting area negatively affected the size of egg clutches; the rate of defence behaviours performed by nesting males negatively influenced the number of females contributing to each nest. © 2016 The Fisheries Society of the British Isles.

Nest survival of American Coots relative to grazing, burning, and water depths

Science.gov (United States)

Austin, Jane E.; Buhl, Deborah A.

2011-01-01

Water and emergent vegetation are key features influencing nest site selection and success for many marsh-nesting waterbirds. Wetland management practices such as grazing, burning, and water-level manipulations directly affect these features and can influence nest survival. We used model selection and before-after-control-impact approaches to evaluate the effects of water depth and four common land-management practices or treatments, i.e., summer grazing, fall grazing, fall burning, and idle (no active treatment) on nest survival of American coots (Fulica americana) nesting at Grays Lake, a large montane wetland in southeast Idaho. The best model included the variables year × treatment, and quadratic functions of date, water depth, and nest age; height of vegetation at the nest did not improve the best model. However, results from the before-after-control-impact analysis indicate that management practices affected nest success via vegetation and involved interactions of hydrology, residual vegetation, and habitat composition. Nest success in idled fields changed little between pre- and post-treatment periods, whereas nest success declined in fields that were grazed or burned, with the most dramatic declines the year following treatments. The importance of water depth may be amplified in this wetland system because of rapid water-level withdrawal during the nesting season. Water and land-use values for area ranchers, management for nesting waterbirds, and long-term wetland function are important considerations in management of water levels and vegetation.

Nest Survival of American Coots Relative to Grazing, Burning, and Water Depths

Directory of Open Access Journals (Sweden)

Jane E. Austin

2011-12-01

Full Text Available Water and emergent vegetation are key features influencing nest site selection and success for many marsh-nesting waterbirds. Wetland management practices such as grazing, burning, and water-level manipulations directly affect these features and can influence nest survival. We used model selection and before-after-control-impact approaches to evaluate the effects of water depth and four common land-management practices or treatments, i.e., summer grazing, fall grazing, fall burning, and idle (no active treatment on nest survival of American coots (Fulica americana nesting at Grays Lake, a large montane wetland in southeast Idaho. The best model included the variables year × treatment, and quadratic functions of date, water depth, and nest age; height of vegetation at the nest did not improve the best model. However, results from the before-after-control-impact analysis indicate that management practices affected nest success via vegetation and involved interactions of hydrology, residual vegetation, and habitat composition. Nest success in idled fields changed little between pre- and post-treatment periods, whereas nest success declined in fields that were grazed or burned, with the most dramatic declines the year following treatments. The importance of water depth may be amplified in this wetland system because of rapid water-level withdrawal during the nesting season. Water and land-use values for area ranchers, management for nesting waterbirds, and long-term wetland function are important considerations in management of water levels and vegetation.

Does nest luminosity play a role in recognition of parasitic eggs in domed nests? A case study of the red bishop

Czech Academy of Sciences Publication Activity Database

Honza, Marcel; Šulc, Michal; Cherry, M. I.

2014-01-01

Roč. 101, č. 12 (2014), s. 1009-1015 ISSN 0028-1042 Institutional support: RVO:68081766 Keywords : Brood parasitism * Domed nest * Egg discrimination * Light conditions * Nest luminosity Subject RIV: EG - Zoology Impact factor: 2.098, year: 2014

Contrasting Effects of Cattle Grazing Intensity on Upland-Nesting Duck Production at Nest and Field Scales in the Aspen Parkland, Canada

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Jeffrey M. Warren

2008-12-01

Full Text Available The Aspen Parkland of Canada is one of the most important breeding areas for temperate nesting ducks in North America. The region is dominated by agricultural land use, with approximately 9.3 million ha in pasture land for cattle grazing. However, the effects of using land for cattle grazing on upland-nesting duck production are poorly understood. The current study was undertaken during 2001 and 2002 to investigate how nest density and nesting success of upland-nesting ducks varied with respect to the intensity of cattle grazing in the Aspen Parkland. We predicted that the removal and trampling of vegetation through cattle grazing would reduce duck nest density. Both positive and negative responses of duck nesting success to grazing have been reported in previous studies, leading us to test competing hypotheses that nesting success would (1 decline linearly with grazing intensity or (2 peak at moderate levels of grazing. Nearly 3300 ha of upland cover were searched during the study. Despite extensive and severe drought, nest searches located 302 duck nests. As predicted, nest density was higher in fields with lower grazing intensity and higher pasture health scores. A lightly grazed field with a pasture score of 85 out of a possible 100 was predicted to have 16.1 nests/100 ha (95% CI = 11.7-22.1, more than five times the predicted nest density of a heavily grazed field with a pasture score of 58 (3.3 nests/100 ha, 95% CI = 2.2-4.5. Nesting success was positively related to nest-site vegetation density across most levels of grazing intensity studied, supporting our hypothesis that reductions in vegetation caused by grazing would negatively affect nesting success. However, nesting success increased with grazing intensity at the field scale. For example, nesting success for a well-concealed nest in a lightly grazed field was 11.6% (95% CI = 3.6-25.0%, whereas nesting success for a nest with the same level of nest-site vegetation in a heavily grazed

The influence of nest-site characteristics on the nesting success of ...

African Journals Online (AJOL)

Choice of nest site has important consequences for nest survival. We examined nest-site characteristics relative to nest success in Karoo Prinias breeding in coastal dwarf shrubland, where high nest predation is the main cause of nest failure. Initially, we compared nests that failed during the building, laying, incubation and ...

Eggshell bacterial load is related to antimicrobial properties of feathers lining barn swallow nests.

Science.gov (United States)

Peralta-Sánchez, Juan Manuel; Soler, Juan José; Martín-Platero, Antonio Manuel; Knight, Rob; Martínez-Bueno, Manuel; Møller, Anders Pape

2014-02-01

The use of feathers to line bird's nests has traditionally been interpreted as having a thermoregulatory function. Feather-degrading bacteria growing on feathers lining nests may have antimicrobial properties, which may provide an additional benefit to lining nests with feathers. We test the hypothesis that the production of antimicrobial substances by feather bacteria affects the microbiological environment of the nest, and therefore the bacterial density on eggshells and, indirectly, hatching success. These effects would be expected to differ between nests lined with pigmented and white feathers, because bacteria grow differently on feathers of different colors. We experimentally manipulated the composition of pigmented and unpigmented feathers in nests of the barn swallow (Hirundo rustica) and studied the antimicrobial properties against the keratin-degrading bacterium Bacillus licheniformis of bacteria isolated from feathers of each color. Analyzed feathers were collected at the end of the incubation period, and antimicrobial activity was defined as the proportion of bacteria from the feathers that produce antibacterial substances effective against B. licheniformis. Our experimental manipulation affected antimicrobial activity, which was higher in nests with only white feathers at the beginning of incubation. Moreover, white feathers showed higher antimicrobial activity than black ones. Interestingly, antimicrobial activity in feathers of one of the colors correlated negatively with bacterial density on feather of the opposite color. Finally, antimicrobial activity of white feathers was negatively related to eggshell bacterial load. These results suggest that antimicrobial properties of feathers in general and of white feathers in particular affect the bacterial environment in nests. This environment in turn affects the bacterial load on eggshells, which may affect hatching success.

PyNEST: a convenient interface to the NEST simulator

Directory of Open Access Journals (Sweden)

Jochen M Eppler

2009-01-01

Full Text Available The neural simulation tool NEST (http://www.nest-initiative.org is a simulator for heterogeneous networks of point neurons or neurons with a small number of compartments. It aims at simulations of large neural systems with more than 10^4 neurons and 10^7 to 10^9 synapses. NEST is implemented in C++ and can be used on a large range of architectures from single-core laptops over multi-core desktop computers to super-computers with thousands of processor cores. Python (http://www.python.org is a modern programming language that has recently received considerable attention in Computational Neuroscience. Python is easy to learn and has many extension modules for scientific computing (e.g. http://www.scipy.org. In this contribution we describe PyNEST, the new user interface to NEST. PyNEST combines NEST’s efficient simulation kernel with the simplicity and flexibility of Python. Compared to NEST’s native simulation language SLI, PyNEST makes it easier to set up simulations, generate stimuli, and analyze simulation results. We describe how PyNEST connects NEST and Python and how it is implemented. With a number of examples, we illustrate how it is used.

Variability in nest survival rates and implications to nesting studies

Science.gov (United States)

Klett, A.T.; Johnson, D.H.

1982-01-01

We used four reasonably large samples (83-213) of Mallard (Anas platyrhynchos) and Blue-winged Teal (A. discors) nests on an interstate highway right-of-way in southcentral North Dakota to evaluate potential biases in hatch-rate estimates. Twelve consecutive, weekly searches for nests were conducted with a cable-chain drag in 1976 and 1977. Nests were revisited at weekly intervals. Four methods were used to estimate hatch rates for the four data sets: the Traditional Method, the Mayfield Method, and two modifications of the Mayfield Method that are sometimes appropriate when daily mortality rates of nests are not constant. Hatch rates and the average age of nests at discovery declined as the interval between searches decreased, suggesting that mortality rates were not constant in our samples. An analysis of variance indicated that daily mortality rates varied with the age of nests in all four samples. Mortality was generally highest during the early laying period, moderately high during the late laying period, and lowest during incubation. We speculate that this relationship of mortality to nest age might be due to the presence of hens at nests or to differences in the vulnerability of nest sites to predation. A modification of the Mayfield Method that accounts for age-related variation in nest mortality was most appropriate for our samples. We suggest methods for conducting nesting studies and estimating nest success for species possessing similar nesting habits.

Nest site selection by Kentish plover suggests a trade-off between nest-crypsis and predator detection strategies.

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Miguel Ángel Gómez-Serrano

Full Text Available Predation is one of the main causes of adult mortality and breeding failure for ground-nesting birds. Micro-habitat structure around nests plays a critical role in minimizing predation risk. Plovers nest in sites with little vegetation cover to maximize the incubating adult visibility, but many studies suggest a trade-off between nest-crypsis and predator detection strategies. However, this trade-off has not been explored in detail because methods used so far do not allow estimating the visibility with regards to critical factors such as slope or plant permeability to vision. Here, we tested the hypothesis that Kentish plovers select exposed sites according to a predator detection strategy, and the hypothesis that more concealed nests survive longer according to a crypsis strategy. To this end, we obtained an accurate estimation of the incubating adult's field of vision through a custom built inverted periscope. Our results showed that plovers selected nest sites with higher visibility than control points randomly selected with regards to humans and dogs, although nests located in sites with higher vegetation cover survived longer. In addition, the flushing distance (i.e., the distance at which incubating adults leave the nest when they detect a potential predator decreased with vegetation cover. Consequently, the advantages of concealing the nest were limited by the ability to detect predators, thus indirectly supporting the existence of the trade-off between crypsis and predator detection. Finally, human disturbance also constrained nest choice, forcing plovers to move to inland sites that were less suitable because of higher vegetation cover, and modulated flushing behavior, since plovers that were habituated to humans left their nests closer to potential predators. This constraint on the width of suitable breeding habitat is particularly relevant for the conservation of Kentish Plover in sand beaches, especially under the current context of

Nesting phenology of marine turtles: insights from a regional comparative analysis on green turtle (Chelonia mydas.

Directory of Open Access Journals (Sweden)

Mayeul Dalleau

Full Text Available Changes in phenology, the timing of seasonal activities, are among the most frequently observed responses to environmental disturbances and in marine species are known to occur in response to climate changes that directly affects ocean temperature, biogeochemical composition and sea level. We examined nesting seasonality data from long-term studies at 8 green turtle (Chelonia mydas rookeries that include 21 specific nesting sites in the South-West Indian Ocean (SWIO. We demonstrated that temperature drives patterns of nesting seasonality at the regional scale. We found a significant correlation between mean annual Sea Surface Temperature (SST and dates of peak nesting with rookeries exposed to higher SST having a delayed nesting peak. This supports the hypothesis that temperature is the main factor determining peak nesting dates. We also demonstrated a spatial synchrony in nesting activity amongst multiple rookeries in the northern part of the SWIO (Aldabra, Glorieuses, Mohéli, Mayotte but not with the eastern and southern rookeries (Europa, Tromelin, differences which could be attributed to females with sharply different adult foraging conditions. However, we did not detect a temporal trend in the nesting peak date over the study period or an inter-annual relation between nesting peak date and SST. The findings of our study provide a better understanding of the processes that drive marine species phenology. The findings will also help to predict their ability to cope with climate change and other environmental perturbations. Despite demonstrating this spatial shift in nesting phenology, no trend in the alteration of nesting dates over more than 20 years was found.

Nest site selection in native and exotic trees by Black-chinned Hummingbirds

Science.gov (United States)

Deborah M. Finch; Jeffrey Kelly

2002-01-01

We studied nest site selection and nesting success in Black-chinned Hummingbirds (Archilochus alexandri) along the middle Rio Grande, New Mexico. The study was conducted in association with an exotic woody plant removal program to determine whether the removal of exotic plants would affect wildlife populations and nesting success, either positively or negatively. Point...

Sunflower (Helianthus annuus) pollination in California's Central Valley is limited by native bee nest site location.

Science.gov (United States)

Sardiñas, Hillary S; Tom, Kathleen; Ponisio, Lauren Catherine; Rominger, Andrew; Kremen, Claire

2016-03-01

The delivery of ecosystem services by mobile organisms depends on the distribution of those organisms, which is, in turn, affected by resources at local and landscape scales. Pollinator-dependent crops rely on mobile animals like bees for crop production, and the spatial relationship between floral resources and nest location for these central-place foragers influences the delivery of pollination services. Current models that map pollination coverage in agricultural regions utilize landscape-level estimates of floral availability and nesting incidence inferred from expert opinion, rather than direct assessments. Foraging distance is often derived from proxies of bee body size, rather than direct measurements of foraging that account for behavioral responses to floral resource type and distribution. The lack of direct measurements of nesting incidence and foraging distances may lead to inaccurate mapping of pollination services. We examined the role of local-scale floral resource presence from hedgerow plantings on nest incidence of ground-nesting bees in field margins and within monoculture, conventionally managed sunflower fields in California's Central Valley. We tracked bee movement into fields using fluorescent powder. We then used these data to simulate the distribution of pollination services within a crop field. Contrary to expert opinion, we found that ground-nesting native bees nested both in fields and edges, though nesting rates declined with distance into field. Further, we detected no effect of field-margin floral enhancements on nesting. We found evidence of an exponential decay rate of bee movement into fields, indicating that foraging predominantly occurred in less than 1% of medium-sized bees' predicted typical foraging range. Although we found native bees nesting within agricultural fields, their restricted foraging movements likely centralize pollination near nest sites. Our data thus predict a heterogeneous distribution of pollination services

Nest Predation Deviates from Nest Predator Abundance in an Ecologically Trapped Bird.

Science.gov (United States)

Hollander, Franck A; Van Dyck, Hans; San Martin, Gilles; Titeux, Nicolas

2015-01-01

In human-modified environments, ecological traps may result from a preference for low-quality habitat where survival or reproductive success is lower than in high-quality habitat. It has often been shown that low reproductive success for birds in preferred habitat types was due to higher nest predator abundance. However, between-habitat differences in nest predation may only weakly correlate with differences in nest predator abundance. An ecological trap is at work in a farmland bird (Lanius collurio) that recently expanded its breeding habitat into open areas in plantation forests. This passerine bird shows a strong preference for forest habitat, but it has a higher nest success in farmland. We tested whether higher abundance of nest predators in the preferred habitat or, alternatively, a decoupling of nest predator abundance and nest predation explained this observed pattern of maladaptive habitat selection. More than 90% of brood failures were attributed to nest predation. Nest predator abundance was more than 50% higher in farmland, but nest predation was 17% higher in forest. Differences between nest predation on actual shrike nests and on artificial nests suggested that parent shrikes may facilitate nest disclosure for predators in forest more than they do in farmland. The level of caution by parent shrikes when visiting their nest during a simulated nest predator intrusion was the same in the two habitats, but nest concealment was considerably lower in forest, which contributes to explaining the higher nest predation in this habitat. We conclude that a decoupling of nest predator abundance and nest predation may create ecological traps in human-modified environments.

Nest-site competition between invasive and native cavity nesting birds and its implication for conservation.

Science.gov (United States)

Charter, Motti; Izhaki, Ido; Ben Mocha, Yitzchak; Kark, Salit

2016-10-01

Nesting cavities are often a limited resource that multiple species use. There is an ongoing discussion on whether invasive cavity nesting birds restrict the availability of this key limited resource. While the answer to this question has important conservation implications, little experimental work has been done to examine it. Here, we aimed to experimentally test whether alien cavity nesting birds affect the occupancy of cavities and the resulting breeding success of native cavity breeders in a large urban park located in Tel Aviv, Israel. Over three breeding seasons, we manipulated the entry size of nest boxes and compared the occupancy and breeding success of birds in nest boxes of two treatments. These included nest boxes with large-entrance and small-entrance holes. The large-entrance holes allowed access for both the native and invasive birds (the two main aliens in the park are the common mynas and rose-ringed parakeets). The smaller-entrance boxes, on the other hand, allowed only the smaller sized native cavity breeders (great tits and house sparrows) to enter the boxes but prevented the alien species from entering. We found that the large-entrance nest boxes were occupied by five different bird species, comprising three natives (great tit, house sparrow, Scops owl) and two invasive species (common myna, rose-ringed parakeet) while the small-entrance boxes were only occupied by the two native species. The alien common mynas and rose-ringed parakeets occupied 77.5% of the large-entrance nest boxes whereas native species, mainly great tits, occupied less than 9% of the large-entrance boxes and 36.5% of the small-entrance boxes. When examining the occupancy of those cavities that were not occupied by the aliens, natives occupied both the small and large-entrance nest boxes equally. Three quarters (78%) of the great tits breeding in the large-entrance boxes were usurped by common mynas during the breeding season and as a result breeding success was

Nest survival of piping plovers at a dynamic reservoir indicates an ecological trap for a threatened population

Science.gov (United States)

Anteau, Michael J.; Shaffer, Terry L.; Sherfy, Mark H.; Sovada, Marsha A.; Stucker, Jennifer H.; Wiltermuth, Mark T.

2012-01-01

In the past 60 years, reservoirs have reshaped riverine ecosystems and transformed breeding habitats used by the threatened piping plover (Charadrius melodus; hereafter plover). Currently, 29% of the Northern Great Plains plover population nests at reservoirs that might function as ecological traps because reservoirs have more diverse habitat features and greater dynamics in water levels than habitats historically used by breeding plovers. We examined factors influencing daily survival rates (DSR) of 346 plover nests at Lake Sakakawea (SAK; reservoir) during 2006–2009 by evaluating multiple a priori models, and we used our best model to hindcast nest success of plovers during 1985–2009. Our observed and hindcast estimates of nest success were low compared to published estimates. Previous findings indicate that plovers prefer nest sites that are low relative to water level. We found that elevation of nests above the water level had a strong positive correlation with DSR because water levels of SAK typically increased throughout the nesting period. Habitat characteristics on the reservoir differ from those that shaped nest-site selection for plovers. Accordingly, extraordinary nest loss occurs there in many years, largely due to inundation of nests, and based on low fledging rates those losses were not compensated by potential changes in chick survival. Therefore, our example supports the concept of ecological traps in birds because it addresses quantitative assessments of habitat preference and productivity over 25 years (since species listing) and affects a large portion of the population.

Factors determining the occurrence of anthropogenic materials in nests of the white stork Ciconia ciconia.

Science.gov (United States)

Jagiello, Zuzanna A; Dylewski, Łukasz; Winiarska, Dominika; Zolnierowicz, Katarzyna M; Tobolka, Marcin

2018-03-13

Birds have been using anthropogenic materials for nest construction for the past few decades. However, there is a trade-off between the use of new nesting material, which is often linked to greater breeding success, and the higher risk of nestling mortality due to entanglement or ingestion of debris. Here, we investigate the incorporation of anthropogenic materials into nests of the white stork Ciconia ciconia, based on a long-term study of a population in Western Poland. We recorded at least one item of debris in 50 and 42% of nests at the egg and nestling stages, respectively. More debris was found in nests located in territories with higher number of anthropogenic material in the surrounding environment. We found a relationship between the age of females, the number of debris in the area surrounding a nest, and the number of debris in the nest. We found no significant effect of the total number of debris in nests on clutch size, number of fledglings, or breeding success. Studies on the influence of the age and sex of individuals in understanding this behaviour and its drivers in bird populations should be continued.

Nest Predation Deviates from Nest Predator Abundance in an Ecologically Trapped Bird.

Directory of Open Access Journals (Sweden)

Franck A Hollander

Full Text Available In human-modified environments, ecological traps may result from a preference for low-quality habitat where survival or reproductive success is lower than in high-quality habitat. It has often been shown that low reproductive success for birds in preferred habitat types was due to higher nest predator abundance. However, between-habitat differences in nest predation may only weakly correlate with differences in nest predator abundance. An ecological trap is at work in a farmland bird (Lanius collurio that recently expanded its breeding habitat into open areas in plantation forests. This passerine bird shows a strong preference for forest habitat, but it has a higher nest success in farmland. We tested whether higher abundance of nest predators in the preferred habitat or, alternatively, a decoupling of nest predator abundance and nest predation explained this observed pattern of maladaptive habitat selection. More than 90% of brood failures were attributed to nest predation. Nest predator abundance was more than 50% higher in farmland, but nest predation was 17% higher in forest. Differences between nest predation on actual shrike nests and on artificial nests suggested that parent shrikes may facilitate nest disclosure for predators in forest more than they do in farmland. The level of caution by parent shrikes when visiting their nest during a simulated nest predator intrusion was the same in the two habitats, but nest concealment was considerably lower in forest, which contributes to explaining the higher nest predation in this habitat. We conclude that a decoupling of nest predator abundance and nest predation may create ecological traps in human-modified environments.

Determinants of stingless bee nest density in lowland dipterocarp forests of Sabah, Malaysia.

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Eltz, Thomas; Brühl, Carsten A; van der Kaars, Sander; Linsenmair, Eduard K

2002-03-01

We measured the nest density of stingless bees (Apidae, Meliponini) in undisturbed and logged-over dipterocarp forests in Sabah, northern Borneo, and evaluated hypotheses on proximate factors leading to the observed variation: population control mediated by (1) nest predation, (2) limitation of nest trees, or (3) food limitation. Per-area nest density varied twentyfold across 14 forest sites and was significantly affected by locality, but not by the degree and history of disturbance. Nest density was generally high in sites located in the Sepilok Forest fragment (mean 8.4 nests/ha), bordering mangroves or plantations. In contrast, nest densities in continuous forests were all low (between 0 and 2.1 nests/ha, mean 0.5 nests/ha). Yearly nest mortality was low (13.5-15.0%) over 4 years of observation and did not vary between forest localities, thus limiting the potential of nest predation (1) in creating the observed variation in nest density. The presence of potential nest trees (2), though positively correlated with nest density, explained only a minute fraction of the observed variation. Nest density was best explained by differences in the pollen resources (3) available to the bees (quantified by analysis of pollen in bee garbage). Across five selected sites the amount of nonforest pollen (from mangrove or crop plants) included in diets of Trigona collina was positively correlated with T. collina nest density. External pollen sources are a likely supplement to bee diets at times when little flowering occurs inside the forest, thus increasing overall bee carrying capacity. Pollen limitation was also indicated by direct measurements of pollen import and foraging activity of T. collina in three selected sites: Pollen traps installed at nests in high-density Sepilok captured significantly more corbicular pollen than colonies in low-density Deramakot. At the same time, morning foraging activity was also greater in Sepilok, indicating a regulatory increase in foraging

Progeny Density and Nest Availability Affect Parasitism Risk and Reproduction in a Solitary Bee (Osmia lignaria) (Hymenoptera: Megachilidae).

Science.gov (United States)

Farzan, Shahla

2018-02-08

Gregarious nesting behavior occurs in a broad diversity of solitary bees and wasps. Despite the prevalence of aggregative nesting, the underlying drivers and fitness consequences of this behavior remain unclear. I investigated the effect of two key characteristics of nesting aggregations (cavity availability and progeny density) on reproduction and brood parasitism rates in the blue orchard bee (Osmia lignaria Say) (Hymenoptera: Megachilidae), a solitary species that nests gregariously and appears to be attracted to nesting conspecifics. To do so, I experimentally manipulated nest cavity availability in a region of northern Utah with naturally occurring populations of O. lignaria. Nest cavity availability had a negative effect on cuckoo bee (Stelis montana Cresson) (Hymenoptera: Megachilidae) parasitism rates, with lower parasitism rates occurring in nest blocks with more available cavities. For both S. montana and the cleptoparasitic blister beetle Tricrania stansburyi Haldeman (Coleoptera: Meloidae), brood parasitism rate was negatively correlated with log-transformed O. lignaria progeny density. Finally, cavity availability had a positive effect on male O. lignaria body weight, with the heaviest male progeny produced in nest blocks with the most cavities. These results suggest that cavity availability and progeny density can have substantial effects on brood parasitism risk and reproduction in this solitary bee species. © The Author(s) 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

The effects of ant nests on soil fertility and plant performance: a meta-analysis.

Science.gov (United States)

Farji-Brener, Alejandro G; Werenkraut, Victoria

2017-07-01

Ants are recognized as one of the major sources of soil disturbance world-wide. However, this view is largely based on isolated studies and qualitative reviews. Here, for the first time, we quantitatively determined whether ant nests affect soil fertility and plant performance, and identified the possible sources of variation of these effects. Using Bayesian mixed-models meta-analysis, we tested the hypotheses that ant effects on soil fertility and plant performance depend on the substrate sampled, ant feeding type, latitude, habitat and the plant response variable measured. Ant nests showed higher nutrient and cation content than adjacent non-nest soil samples, but similar pH. Nutrient content was higher in ant refuse materials than in nest soils. The fertilizer effect of ant nests was also higher in dry habitats than in grasslands or savannas. Cation content was higher in nests of plant-feeding ants than in nests of omnivorous species, and lower in nests from agro-ecosystems than in nests from any other habitat. Plants showed higher green/root biomass and fitness on ant nests soils than in adjacent, non-nest sites; but plant density and diversity were unaffected by the presence of ant nests. Root growth was particularly higher in refuse materials than in ant nest soils, in leaf-cutting ant nests and in deserts habitats. Our results confirm the major role of ant nests in influencing soil fertility and vegetation patterns and provide information about the factors that mediate these effects. First, ant nests improve soil fertility mainly through the accumulation of refuse materials. Thus, different refuse dump locations (external or in underground nest chambers) could benefit different vegetation life-forms. Second, ant nests could increase plant diversity at larger spatial scales only if the identity of favoured plants changes along environmental gradients (i.e. enhancing β-diversity). Third, ant species that feed on plants play a relevant role fertilizing soils

Canada goose nest survival at rural wetlands in north-central Iowa

Science.gov (United States)

Ness, Brenna N.; Klaver, Robert W.

2016-01-01

The last comprehensive nest survival study of the breeding giant Canada goose (Branta canadensis maxima) population in Iowa, USA, was conducted >30 years ago during a period of population recovery, during which available nesting habitat consisted primarily of artificial nest structures. Currently, Iowa's resident goose population is stable and nests in a variety of habitats. We analyzed the effects of available habitat on nest survival and how nest survival rates compared with those of the expanding goose population studied previously to better understand how to maintain a sustainable Canada goose population in Iowa. We documented Canada goose nest survival at rural wetland sites in north-central Iowa. We monitored 121 nests in 2013 and 149 nests in 2014 at 5 Wildlife Management Areas (WMAs) with various nesting habitats, including islands, muskrat (Ondatra zibethicus) houses, and elevated nest structures. We estimated daily nest-survival rate using the nest survival model in Program MARK. Survival was influenced by year, site, stage, presence of a camera, nest age, and an interaction between nest age and stage. Nest success rates for the 28-day incubation period by site and year combination ranged from 0.10 to 0.84. Nest survival was greatest at sites with nest structures (β = 17.34). Nest survival was negatively affected by lowered water levels at Rice Lake WMA (2013 β = −0.77, nest age β = −0.07). Timing of water-level drawdowns for shallow lake restorations may influence nest survival rates.

Is it safe to nest near conspicuous neighbours? Spatial patterns in predation risk associated with the density of American Golden-Plover nests.

Science.gov (United States)

Giroux, Marie-Andrée; Trottier-Paquet, Myriam; Bêty, Joël; Lamarre, Vincent; Lecomte, Nicolas

2016-01-01

Predation is one of the main factors explaining nesting mortality in most bird species. Birds can avoid nest predation or reduce predation pressure by breeding at higher latitude, showing anti-predator behaviour, selecting nest sites protected from predators, and nesting in association with protective species. American Golden-Plovers (Pluvialis dominica) defend their territory by using various warning and distraction behaviours displayed at varying levels of intensity (hereafter "conspicuous behaviour"), as well as more aggressive behaviours such as aerial attacks, but only in some populations. Such antipredator behaviour has the potential to repel predators and thus benefit the neighbouring nests by decreasing their predation risk. Yet, conspicuous behaviour could also attract predators by signalling the presence of a nest. To test for the existence of a protective effect associated with the conspicuous antipredator behaviour of American Golden-Plovers, we studied the influence of proximity to plover nests on predation risk of artificial nests on Igloolik Island (Nunavut, Canada) in July 2014. We predicted that the predation risk of artificial nests would decrease with proximity to and density of plover nests. We monitored 18 plover nests and set 35 artificial nests at 30, 50, 100, 200, and 500 m from seven of those plover nests. We found that the predation risk of artificial nests increases with the density of active plover nests. We also found a significant negative effect of the distance to the nearest active protector nest on predation risk of artificial nests. Understanding how the composition and structure of shorebird communities generate spatial patterns in predation risks represents a key step to better understand the importance of these species of conservation concern in tundra food webs.

Modeling nest-survival data: a comparison of recently developed methods that can be implemented in MARK and SAS

Directory of Open Access Journals (Sweden)

Rotella, J. J.

2004-06-01

Full Text Available Estimating nest success and evaluating factors potentially related to the survival rates of nests are key aspects of many studies of avian populations. A strong interest in nest success has led to a rich literature detailing a variety of estimation methods for this vital rate. In recent years, modeling approaches have undergone especially rapid development. Despite these advances, most researchers still employ Mayfield’s ad-hoc method (Mayfield, 1961 or, in some cases, the maximum-likelihood estimator of Johnson (1979 and Bart & Robson (1982. Such methods permit analyses of stratified data but do not allow for more complex and realistic models of nest survival rate that include covariates that vary by individual, nest age, time, etc. and that may be continuous or categorical. Methods that allow researchers to rigorously assess the importance of a variety of biological factors that might affect nest survival rates can now be readily implemented in Program MARK and in SAS’s Proc GENMOD and Proc NLMIXED. Accordingly, use of Mayfield’s estimator without first evaluating the need for more complex models of nest survival rate cannot be justified. With the goal of increasing the use of more flexible methods, we first describe the likelihood used for these models and then consider the question of what the effective sample size is for computation of AICc. Next, we consider the advantages and disadvantages of these different programs in terms of ease of data input and model construction; utility/flexibility of generated estimates and predictions; ease of model selection; and ability to estimate variance components. An example data set is then analyzed using both MARK and SAS to demonstrate implementation of the methods with various models that contain nest-, group- (or block-, and time-specific covariates. Finally, we discuss improvements that would, if they became available, promote a better general understanding of nest survival rates.

Climate change and nesting behaviour in vertebrates: a review of the ecological threats and potential for adaptive responses.

Science.gov (United States)

Mainwaring, Mark C; Barber, Iain; Deeming, Denis C; Pike, David A; Roznik, Elizabeth A; Hartley, Ian R

2017-11-01

Nest building is a taxonomically widespread and diverse trait that allows animals to alter local environments to create optimal conditions for offspring development. However, there is growing evidence that climate change is adversely affecting nest-building in animals directly, for example via sea-level rises that flood nests, reduced availability of building materials, and suboptimal sex allocation in species exhibiting temperature-dependent sex determination. Climate change is also affecting nesting species indirectly, via range shifts into suboptimal nesting areas, reduced quality of nest-building environments, and changes in interactions with nest predators and parasites. The ability of animals to adapt to sustained and rapid environmental change is crucial for the long-term persistence of many species. Many animals are known to be capable of adjusting nesting behaviour adaptively across environmental gradients and in line with seasonal changes, and this existing plasticity potentially facilitates adaptation to anthropogenic climate change. However, whilst alterations in nesting phenology, site selection and design may facilitate short-term adaptations, the ability of nest-building animals to adapt over longer timescales is likely to be influenced by the heritable basis of such behaviour. We urgently need to understand how the behaviour and ecology of nest-building in animals is affected by climate change, and particularly how altered patterns of nesting behaviour affect individual fitness and population persistence. We begin our review by summarising how predictable variation in environmental conditions influences nest-building animals, before highlighting the ecological threats facing nest-building animals experiencing anthropogenic climate change and examining the potential for changes in nest location and/or design to provide adaptive short- and long-term responses to changing environmental conditions. We end by identifying areas that we believe warrant the

Time-lapse video sysem used to study nesting gyrfalcons

Science.gov (United States)

Booms, Travis; Fuller, Mark R.

2003-01-01

We used solar-powered time-lapse video photography to document nesting Gyrfalcon (Falco rusticolus) food habits in central West Greenland from May to July in 2000 and 2001. We collected 2677.25 h of videotape from three nests, representing 94, 87, and 49% of the nestling period at each nest. The video recorded 921 deliveries of 832 prey items. We placed 95% of the items into prey categories. The image quality was good but did not reveal enough detail to identify most passerines to species. We found no evidence that Gyrfalcons were negatively affected by the video system after the initial camera set-up. The video system experienced some mechanical problems but proved reliable. The system likely can be used to effectively document the food habits and nesting behavior of other birds, especially those delivering large prey to a nest or other frequently used site.

Observer visitation frequency and success of mourning dove nests: A field experiment

Science.gov (United States)

Nichols, J.D.; Percival, H.F.; Coon, R.A.; Conroy, M.J.; Hensler, G.L.; Hines, J.E.

1984-01-01

Field studies of nesting success generally require visits by the investigator to the nests under study. Such visits may themselves influence nesting success, however, and this possibility has been discussed and investigated by a number of workers with a variety of bird species. Livezey (1980) reviewed the relevant literature for duck nests and noted that most studies failed to demonstrate differences in nesting success between visited nests and those not visited. Livezey (1980) found in his own work that nest abandonment may have occurred as a result of disturbance by observers but that nest predation was not related to time spent by observers at nests or number of observers approaching nests. Various components of nesting and breeding success in seabirds are thought to be adversely affected by human disturbance and nest visitation (Gillett et al. 1975, Robert and Ralph 1975, Ollason and Dunnet 1980). Upland, ground-nesting species have also been studied (e.g. Stoddard 1931, Evans and Wolfe 1967, Henry 1969, Roseberry and Klimstra 1970, Klimstra and Roseberry 1975), and, although conclusions have varied, a number of these workers found no effect of observers on nest-predation rates.

Nest predation and reproductive traits in small passerines: a comparative approach

Science.gov (United States)

Yanes, Miguel; Suárez, Francisco

Nest predation can be a decisive factor in the evolution of bird reproduction strategies. This paper compares several reproductive traits in small passerines on the Iberian Peninsula (n=31) with the probability of daily nest survival from predation. We consider the phylogenetic relationships between species by means of an analysis according to three models of evolutionary change: Brownian, punctuational and GRAFEN'S arbitrary. In this comparative evolutionary scenario, clutch size, egg volume and incubation period appear not to change in relation to nest predation, while the nestling phase duration is a positively-related parameter to daily nest survival from predation. These results are consistent for all models of evolutionary change. Thus, from the perspective of nest predation, the nestling period is the most important evolutionary parameter in small passerines. A hypothetical influence of nest predation on passerine clutch and egg size should only be regarded as an indirect factor, linked to the relationship between these parameters and the duration of the nestling period.

The effects of cavity length on nest size, sex ratio and mortality of Centris (Heterocentris) analis (Hymenoptera, Apidae, Centridini)

OpenAIRE

Alonso , Juliana; Silva , Janaina; Garófalo , Carlos

2012-01-01

International audience; This study investigated the effects of different cavity lengths in trap-nests on the number of cells constructed per nest, sex ratio and mortality of offspring of Centris analis at three sites in Ribeirão Preto, São Paulo, Brazil. Cavity length did not affect the occupation rates of the trap-nests, with the exception of a preference for the shortest trap-nests found at one site. The number of cells per nest increased with trap-nest length. Cavity length affected neithe...

Interactive effects between nest microclimate and nest vegetation structure confirm microclimate thresholds for Lesser Prairie-Chicken nest survival

Science.gov (United States)

Grisham, Blake A.; Godar, Alixandra J.; Boal, Clint W.; Haukos, David A.

2016-01-01

The range of Lesser Prairie-Chickens (Tympanuchus pallidicinctus) spans 4 unique ecoregions along 2 distinct environmental gradients. The Sand Shinnery Oak Prairie ecoregion of the Southern High Plains of New Mexico and Texas is environmentally isolated, warmer, and more arid than the Short-Grass, Sand Sagebrush, and Mixed-Grass Prairie ecoregions in Colorado, Kansas, Oklahoma, and the northeast panhandle of Texas. Weather is known to influence Lesser Prairie-Chicken nest survival in the Sand Shinnery Oak Prairie ecoregion; regional variation may also influence nest microclimate and, ultimately, survival during incubation. To address this question, we placed data loggers adjacent to nests during incubation to quantify temperature and humidity distribution functions in 3 ecoregions. We developed a suite of a priori nest survival models that incorporated derived microclimate parameters and visual obstruction as covariates in Program MARK. We monitored 49 nests in Mixed-Grass, 22 nests in Sand Shinnery Oak, and 30 nests in Short-Grass ecoregions from 2010 to 2014. Our findings indicated that (1) the Sand Shinnery Oak Prairie ecoregion was hotter and drier during incubation than the Mixed- and Short-Grass ecoregions; (2) nest microclimate varied among years within ecoregions; (3) visual obstruction was positively associated with nest survival; but (4) daily nest survival probability decreased by 10% every half-hour when temperature was greater than 34°C and vapor pressure deficit was less than −23 mmHg during the day (about 0600–2100 hours). Our major finding confirmed microclimate thresholds for nest survival under natural conditions across the species' distribution, although Lesser Prairie-Chickens are more likely to experience microclimate conditions that result in nest failures in the Sand Shinnery Oak Prairie ecoregion. The species would benefit from identification of thermal landscapes and management actions that promote cooler, more humid nest microclimates.

Nest Mosquito Trap quantifies contact rates between nesting birds and mosquitoes.

Science.gov (United States)

Caillouët, Kevin A; Riggan, Anna E; Rider, Mark; Bulluck, Lesley P

2012-06-01

Accurate estimates of host-vector contact rates are required for precise determination of arbovirus transmission intensity. We designed and tested a novel mosquito collection device, the Nest Mosquito Trap (NMT), to collect mosquitoes as they attempt to feed on unrestrained nesting birds in artificial nest boxes. In the laboratory, the NMT collected nearly one-third of the mosquitoes introduced to the nest boxes. We then used these laboratory data to estimate our capture efficiency of field-collected bird-seeking mosquitoes collected over 66 trap nights. We estimated that 7.5 mosquitoes per trap night attempted to feed on nesting birds in artificial nest boxes. Presence of the NMT did not have a negative effect on avian nest success when compared to occupied nest boxes that were not sampled with the trap. Future studies using the NMT may elucidate the role of nestlings in arbovirus transmission and further refine estimates of nesting bird and vector contact rates. © 2012 The Society for Vector Ecology.

Vegetation Changes in a Native Forest Produced by Atta vollenweideri Forel 1893 (Hymenoptera: Formicidae) Nests.

Science.gov (United States)

Sabattini, J A; Sabattini, R A; Cian, J C; Sabattini, I A

2018-02-01

Herbivory is an important factor to generate spatial mosaics with variations in a plant community composition and organization. The objective of this work was to determine the impact of Atta vollenweideri Forel 1893 nests on herbaceous and shrub vegetation in a degraded native forest of the Espinal ecoregion. The study was carried out in the Protected Area and Multiple Use Nature Reserve called Estancia "El Carayá" (Entre Ríos, Argentina). Ten A. vollenweideri nests were selected by simple random sampling through internal roads, and two transects were drawn from the center of the nest (0 m) up to 60 m away in opposite directions. The line intercept method was used to quantify the percentage of vegetation cover of herbaceous and shrub species, while the floristic composition was estimated by the Canfield method. Afterwards, a nonparametric test between positions and a conglomerate analysis to evaluated distance were applied. Grass species, legumes, and sedges fell in the adjacent areas to nests, highlighting the bare soil at the crest and base of the nests. Fifteen plant species were identified, and two families correspond to monocotyledonous and dicotyledonous species. In conclusion, the nests of A. vollenweideri affect the community of herbaceous and shrub vegetation of the studied degraded native forest of the Espinal ecoregion since these ants perform a high selection of herbaceous species considered as pioneers of plant successions.

Millipedes (Diplopoda) in birds' nests

Czech Academy of Sciences Publication Activity Database

Tajovský, Karel; Mock, A.; Krumpál, M.

2001-01-01

Roč. 37, - (2001), s. 321-323 ISSN 1164-5563 Institutional research plan: CEZ:AV0Z6066911 Keywords : bird s nest s * microsites * millipedes Subject RIV: EH - Ecology, Behaviour Impact factor: 0.317, year: 2001

Is it safe to nest near conspicuous neighbours? Spatial patterns in predation risk associated with the density of American Golden-Plover nests

Directory of Open Access Journals (Sweden)

Marie-Andrée Giroux

2016-08-01

Full Text Available Predation is one of the main factors explaining nesting mortality in most bird species. Birds can avoid nest predation or reduce predation pressure by breeding at higher latitude, showing anti-predator behaviour, selecting nest sites protected from predators, and nesting in association with protective species. American Golden-Plovers (Pluvialis dominica defend their territory by using various warning and distraction behaviours displayed at varying levels of intensity (hereafter “conspicuous behaviour”, as well as more aggressive behaviours such as aerial attacks, but only in some populations. Such antipredator behaviour has the potential to repel predators and thus benefit the neighbouring nests by decreasing their predation risk. Yet, conspicuous behaviour could also attract predators by signalling the presence of a nest. To test for the existence of a protective effect associated with the conspicuous antipredator behaviour of American Golden-Plovers, we studied the influence of proximity to plover nests on predation risk of artificial nests on Igloolik Island (Nunavut, Canada in July 2014. We predicted that the predation risk of artificial nests would decrease with proximity to and density of plover nests. We monitored 18 plover nests and set 35 artificial nests at 30, 50, 100, 200, and 500 m from seven of those plover nests. We found that the predation risk of artificial nests increases with the density of active plover nests. We also found a significant negative effect of the distance to the nearest active protector nest on predation risk of artificial nests. Understanding how the composition and structure of shorebird communities generate spatial patterns in predation risks represents a key step to better understand the importance of these species of conservation concern in tundra food webs.

Nest site selection in a hot desert : Trade-off between microclimate and predation risk?

NARCIS (Netherlands)

Tieleman, B. Irene; van Noordwijk, Hendrika J.; Williams, Joseph B.

Nest placement affects the risk of predation on both eggs and incubating parents and determines the microclimate for incubation, two functions that may be in conflict, especially in hot deserts. We studied the roles of microclimate and nest predation on nest site selection by Hoopoe Larks (Alaemon

A review of the nest protection hypothesis: does inclusion of fresh green plant material in birds' nests reduce parasite infestation?

Science.gov (United States)

Scott-Baumann, James F; Morgan, Eric R

2015-07-01

The use of aromatic plants and their essential oils for ectoparasite treatment is a field of growing interest. Several species of birds regularly introduce aromatic herbs into their nests putatively to reduce parasites. The behaviour is most often seen in cavity nesting birds and after nest building has finished. The plants are included in a non-structural manner and are often strongly aromatic. Various different hypotheses have been proposed regarding the function of this behaviour; from the plants altering some non-living factor in the nest (crypsis, water loss and insulation hypotheses) to them being involved in mate selection (mate hypothesis) or even having a beneficial effect, direct or indirect, on chicks (drug or nest protection hypothesis, NPH). Many studies have been carried out over the years observing and experimentally testing these hypotheses. This review focuses on studies involving the most popular of these hypotheses, the NPH: that plants decrease nest parasites or pathogens, thereby conveying positive effects to the chicks, allowing the behaviour to evolve. Studies providing observational evidence towards this hypothesis and those experimentally testing it are discussed.

Mourning Dove nesting habitat and nest success in Central Missouri

Science.gov (United States)

Drobney, R.D.; Schulz, J.H.; Sheriff, S.L.; Fuemmeler, W.J.

1998-01-01

Previous Mourning Dove (Zenaida macroura) nesting studies conducted in areas containing a mixture of edge and continuous habitats have focused on edge habitats. Consequently, little is known about the potential contribution of continuous habitats to dove production. In this study we evaluated the relative importance of these two extensive habitat types by monitoring the habitat use and nest success of 59 radio-marked doves during 1990-1991 in central Missouri. Of 83 nests initiated by our marked sample, most (81.9%) were located in edge habitats. Although continuous habitats were selected less as nest sites, the proportion of successful nests did not differ significantly from that in edge habitats. Our data indicate that continuous habitats should not be considered marginal nesting habitat. If the intensity of use and nest success that we observed are representative regionally or nationally, continuous habitats could contribute substantially to annual Mourning Dove production because of the high availability of these habitats throughout much of the Mourning Dove breeding range.

Contrast in edge vegetation structure modifies the predation risk of natural ground nests in an agricultural landscape.

Directory of Open Access Journals (Sweden)

Nicole A Schneider

Full Text Available Nest predation risk generally increases nearer forest-field edges in agricultural landscapes. However, few studies test whether differences in edge contrast (i.e. hard versus soft edges based on vegetation structure and height affect edge-related predation patterns and if such patterns are related to changes in nest conspicuousness between incubation and nestling feeding. Using data on 923 nesting attempts we analyse factors influencing nest predation risk at different edge types in an agricultural landscape of a ground-cavity breeding bird species, the Northern Wheatear (Oenanthe oenanthe. As for many other bird species, nest predation is a major determinant of reproductive success in this migratory passerine. Nest predation risk was higher closer to woodland and crop field edges, but only when these were hard edges in terms of ground vegetation structure (clear contrast between tall vs short ground vegetation. No such edge effect was observed at soft edges where adjacent habitats had tall ground vegetation (crop, ungrazed grassland. This edge effect on nest predation risk was evident during the incubation stage but not the nestling feeding stage. Since wheatear nests are depredated by ground-living animals our results demonstrate: (i that edge effects depend on edge contrast, (ii that edge-related nest predation patterns vary across the breeding period probably resulting from changes in parental activity at the nest between the incubation and nestling feeding stage. Edge effects should be put in the context of the nest predator community as illustrated by the elevated nest predation risk at hard but not soft habitat edges when an edge is defined in terms of ground vegetation. These results thus can potentially explain previously observed variations in edge-related nest predation risk.

Soil attributes drive nest-site selection by the campo miner Geositta poeciloptera

Science.gov (United States)

Teixeira, João Paulo Gusmão; Solar, Ricardo; Vasconcelos, Bruno Nery F.; Fernandes, Raphael B. A.; Lopes, Leonardo Esteves

2018-01-01

Substrate type is a key-factor in nest-site selection and nest architecture of burrowing birds. However, little is known about which factors drive nest-site selection for these species, especially in the tropics. We studied the influence of soil attributes on nest-site selection by the campo miner Geositta poeciloptera, an open grassland bird that builds its nests within soil cavities. For all nests found, we measured the depth of the nest cavity and the resistance of the soil to penetration, and identified the soil horizon in which the nest was located. In soil banks with nests, we collected soil samples for granulometric analysis around each nest cavity, while in soil banks without nests we collected these samples at random points. From 43 nests found, 86% were located in the deeper soil horizons (C-horizon), and only 14% in the shallower horizons (B-horizon). Granulometric analysis showed that the C-horizons possessed a high similar granulometric composition, with high silt and low clay contents. These characteristics are associated with a low degree of structural development of the soil, which makes it easier to excavate. Contrarily, soil resistance to penetration does not seem to be an important criterion for nest site selection, although nests in more resistant the soils tend to have shallower nest cavities. Among the soil banks analyzed, 40% of those without cavities possessed a larger proportion of B-horizon relative to the C-horizon, and their texture was more clayey. On the other hand, almost all soil banks containing nest cavities had a larger C-horizon and a silty texture, indicating that soil attributes drive nest-site selection by G. poeciloptera. Thus, we conclude that the patchy distribution of G. poeciloptera can attributed to the infrequent natural exposure of the C-horizon in the tropical region, where well developed, deep and permeable soils are more common. PMID:29381768

Soil attributes drive nest-site selection by the campo miner Geositta poeciloptera.

Science.gov (United States)

Meireles, Ricardo Camargos de; Teixeira, João Paulo Gusmão; Solar, Ricardo; Vasconcelos, Bruno Nery F; Fernandes, Raphael B A; Lopes, Leonardo Esteves

2018-01-01

Substrate type is a key-factor in nest-site selection and nest architecture of burrowing birds. However, little is known about which factors drive nest-site selection for these species, especially in the tropics. We studied the influence of soil attributes on nest-site selection by the campo miner Geositta poeciloptera, an open grassland bird that builds its nests within soil cavities. For all nests found, we measured the depth of the nest cavity and the resistance of the soil to penetration, and identified the soil horizon in which the nest was located. In soil banks with nests, we collected soil samples for granulometric analysis around each nest cavity, while in soil banks without nests we collected these samples at random points. From 43 nests found, 86% were located in the deeper soil horizons (C-horizon), and only 14% in the shallower horizons (B-horizon). Granulometric analysis showed that the C-horizons possessed a high similar granulometric composition, with high silt and low clay contents. These characteristics are associated with a low degree of structural development of the soil, which makes it easier to excavate. Contrarily, soil resistance to penetration does not seem to be an important criterion for nest site selection, although nests in more resistant the soils tend to have shallower nest cavities. Among the soil banks analyzed, 40% of those without cavities possessed a larger proportion of B-horizon relative to the C-horizon, and their texture was more clayey. On the other hand, almost all soil banks containing nest cavities had a larger C-horizon and a silty texture, indicating that soil attributes drive nest-site selection by G. poeciloptera. Thus, we conclude that the patchy distribution of G. poeciloptera can attributed to the infrequent natural exposure of the C-horizon in the tropical region, where well developed, deep and permeable soils are more common.

Landscape position moderates how ant nests affect hydrology and soil chemistry across a Chihuahuan Desert watershed

Science.gov (United States)

Ants moderate the supply of critical resources such as water and nutrients in desert environments by changing the physical arrangement of soils during nest construction. We measured water infiltration and soil physical and chemical properties on and off the nests of two ant species (Pogonomyrmex rug...

Construction patterns of birds’ nests provide insight into nest-building behaviours

Directory of Open Access Journals (Sweden)

Lucia Biddle

2017-02-01

Full Text Available Previous studies have suggested that birds and mammals select materials needed for nest building based on their thermal or structural properties, although the amounts or properties of the materials used have been recorded for only a very small number of species. Some of the behaviours underlying the construction of nests can be indirectly determined by careful deconstruction of the structure and measurement of the biomechanical properties of the materials used. Here we examined this idea in an investigation of Bullfinch (Pyrrhula pyrrhula nests as a model for open-nesting songbird species that construct a “twig” nest, and tested the hypothesis that materials in different parts of nests serve different functions. The quantities of materials present in the nest base, sides and cup were recorded before structural analysis. Structural analysis showed that the base of the outer nests were composed of significantly thicker, stronger and more rigid materials compared to the side walls, which in turn were significantly thicker, stronger and more rigid than materials used in the cup. These results suggest that the placement of particular materials in nests may not be random, but further work is required to determine if the final structure of a nest accurately reflects the construction process.

Construction patterns of birds’ nests provide insight into nest-building behaviours

Science.gov (United States)

Goodman, Adrian M.

2017-01-01

Previous studies have suggested that birds and mammals select materials needed for nest building based on their thermal or structural properties, although the amounts or properties of the materials used have been recorded for only a very small number of species. Some of the behaviours underlying the construction of nests can be indirectly determined by careful deconstruction of the structure and measurement of the biomechanical properties of the materials used. Here we examined this idea in an investigation of Bullfinch (Pyrrhula pyrrhula) nests as a model for open-nesting songbird species that construct a “twig” nest, and tested the hypothesis that materials in different parts of nests serve different functions. The quantities of materials present in the nest base, sides and cup were recorded before structural analysis. Structural analysis showed that the base of the outer nests were composed of significantly thicker, stronger and more rigid materials compared to the side walls, which in turn were significantly thicker, stronger and more rigid than materials used in the cup. These results suggest that the placement of particular materials in nests may not be random, but further work is required to determine if the final structure of a nest accurately reflects the construction process. PMID:28265501

Construction patterns of birds' nests provide insight into nest-building behaviours.

Science.gov (United States)

Biddle, Lucia; Goodman, Adrian M; Deeming, D Charles

2017-01-01

Previous studies have suggested that birds and mammals select materials needed for nest building based on their thermal or structural properties, although the amounts or properties of the materials used have been recorded for only a very small number of species. Some of the behaviours underlying the construction of nests can be indirectly determined by careful deconstruction of the structure and measurement of the biomechanical properties of the materials used. Here we examined this idea in an investigation of Bullfinch ( Pyrrhula pyrrhula ) nests as a model for open-nesting songbird species that construct a "twig" nest, and tested the hypothesis that materials in different parts of nests serve different functions. The quantities of materials present in the nest base, sides and cup were recorded before structural analysis. Structural analysis showed that the base of the outer nests were composed of significantly thicker, stronger and more rigid materials compared to the side walls, which in turn were significantly thicker, stronger and more rigid than materials used in the cup. These results suggest that the placement of particular materials in nests may not be random, but further work is required to determine if the final structure of a nest accurately reflects the construction process.

Factors Affecting University Library Website Design

OpenAIRE

Kim, Yongi-Mi; University of Oklahoma

2011-01-01

Existing studies have extensively explored factors that affect users’ intentions to use university library website resources (ULWR); yet little attention has been given to factors affecting university library website design. This paper investigates factors that affect university library website design and assesses the success of the university library website from both designers’ and users’ perspectives. The findings show that when planning a website, university web designers consider univers...

Anthropogenic debris in the nests of kelp gulls in South Africa.

Science.gov (United States)

Witteveen, Minke; Brown, Mark; Ryan, Peter G

2017-01-30

Anthropogenic debris results in detrimental interactions with many marine species. Several seabirds include debris items in their nests, which can lead to entanglement of chicks and adults, resulting in injury or death. Anthropogenic debris was found in 4-67% of kelp gull Larus dominicanus nests in seven colonies in the Western Cape, South Africa. Nests contained two types of litter: items included in the nest structure during construction (mainly ropes and straps), and regurgitated items (mainly bags and food wrappers) that probably accumulate primarily during the chick-rearing period. Debris used in nest construction was more likely to injure gulls, and was found mainly at coastal sites where there was little natural vegetation for construction. Distance to the nearest urban waste landfill significantly affected the occurrence of debris items in nests, especially dietary-derived items. The amount of debris in kelp gull nests highlights the need for improved debris management in South Africa. Copyright © 2016 Elsevier Ltd. All rights reserved.

Nest survival is influenced by parental behaviour and heterospecifics in a mixed-species colony

Science.gov (United States)

Brussee, Brianne E.; Coates, Peter S.; Hothem, Roger L.; Howe, Kristy; Casazza, Michael L.; Eadie, John M.

2016-01-01

Studies of avian nest success often focus on examining influences of variation in environmental and seasonal factors. However, in-depth evaluations can also incorporate variation in individual incubation behaviour to further advance our understanding of avian reproductive ecology. We examined these relationships in colonially nesting Black-crowned Night-Herons Nycticorax nycticorax using intensive video-monitoring methods to quantify incubation behaviours. We modelled nest survival as a function of both extrinsic factors and incubation behaviours over a 3-year period (2010–12) on Alcatraz Island, USA. Model-averaged parameter estimates indicated that nest survival increased as a function of greater incubation constancy (% of time spent incubating eggs within a 24-h period), and average daily precipitation throughout the nesting stage. Common Ravens Corvus corax are the only known nest predator of Night-Herons on Alcatraz Island, as on many other coastal Pacific islands. We also investigated the effects of heterospecific nesting of California Gulls Larus californicus and Western Gulls Larus occidentalis in a mixed-species colony with Night-Herons, based on nesting proximity data collected over a 2-year period (2011–12). This second analysis indicated that, in addition to incubation behaviours, nesting heterospecifics are an important factor for explaining variation in Night-Heron nest survival. However, contrary to our original expectation, we found that Night-Herons experienced increased nest survival with increasing distance from gull colony boundaries. These results may apply to other areas with multiple colonial nesting species and similar predator communities and climatic patterns.

Landscape-moderated bird nest predation in hedges and forest edges

Science.gov (United States)

Ludwig, Martin; Schlinkert, Hella; Holzschuh, Andrea; Fischer, Christina; Scherber, Christoph; Trnka, Alfréd; Tscharntke, Teja; Batáry, Péter

2012-11-01

Landscape-scale agricultural intensification has caused severe declines in biodiversity. Hedges and forest remnants may mitigate biodiversity loss by enhancing landscape heterogeneity and providing habitat to a wide range of species, including birds. However, nest predation, the major cause of reproductive failure of birds, has been shown to be higher in forest edges than in forest interiors. Little is known about how spatial arrangement (configuration) of hedges affects the avian nest predation. We performed an experiment with artificial ground and elevated nests (resembling yellowhammer and whitethroat nests) baited with quail and plasticine eggs. Nests were placed in three habitat types with different degrees of isolation from forests: forest edges, hedges connected to forests and hedges isolated from forests. Nest predation was highest in forest edges, lowest in hedges connected to forests and intermediate in isolated hedges. In the early breeding season, we found similar nest predation on ground and elevated nests, but in the late breeding season nest predation was higher on ground nests than on elevated nests. Small mammals were the main predators of ground nests and appeared to be responsible for the increase in predation from early to late breeding season, whereas the elevated nests were mainly depredated by small birds and small mammals. High predation pressure at forest edges was probably caused by both forest and open-landscape predators. The influence of forest predators may be lower at hedges, leading to lower predation pressure than in forest edges. Higher predation pressure in isolated than connected hedges might be an effect of concentration of predators in these isolated habitats. We conclude that landscape configuration of hedges is important in nest predation, with connected hedges allowing higher survival than isolated hedges and forest edges.

The importance of microclimate variation in determining size, growth and survival of avian offspring: experimental evidence from a cavity nesting passerine.

Science.gov (United States)

Dawson, Russell D; Lawrie, Cheyenne C; O'Brien, Erin L

2005-07-01

Organisms are expected to balance energy allocation in such a way that fitness is maximized. While much research has focussed on allocation strategies of reproducing parents, in particular birds, relatively little attention has been paid to how nestlings allocate energy while in the nest. Nestling birds are faced with a trade-off between devoting energy to growth or to thermoregulation, and in altricial species it is likely that the thermal environment of the nest site influences the nature of this trade-off. Here, we experimentally investigate how altering the microclimate of nests affects the growth, size and survival, as well as cell-mediated immune (CMI) response, of nestling tree swallows (Tachycineta bicolor) in a temperate environment. We place air-activated heating pads in nests of swallows when young were between 4 days and 16 days of age, and compared performance of offspring to control nests. Our manipulation raised temperatures of heated nests by approximately 5 degrees C compared to control nests. Offspring in heated nests had enhanced survival while in the nest, and we also found that they were heavier and had longer ninth primary feathers at 16 days of age. In addition, heating nest boxes resulted in significantly faster growth of primaries, and there was a trend for growth rates of mass to also be higher in heated nests. There were no significant differences between heated and control nests in growth rate or size of tarsus at age 16 days, and we speculate that this lack of response to elevated nest temperatures may be due to growth of skeletal structures being limited by other factors such as calcium availability. We also found no difference between heated and control nests in CMI response. Nonetheless, our results show overall that increasing temperatures of nests has significant benefits that enhance the fitness of offspring. As provisioning rates to offspring did not differ between heated and control nests, we suspect that the beneficial effects

Identifying effective actions to guide volunteer-based and nationwide conservation efforts for a ground-nesting farmland bird.

Science.gov (United States)

Santangeli, Andrea; Arroyo, Beatriz; Millon, Alexandre; Bretagnolle, Vincent

2015-08-01

1. Modern farming practices threaten wildlife in different ways, and failure to identify the complexity of multiple threats acting in synergy may result in ineffective management. To protect ground-nesting birds in farmland, monitoring and mitigating impacts of mechanical harvesting is crucial. 2. Here, we use 6 years of data from a nationwide volunteer-based monitoring scheme of the Montagu's harrier, a ground-nesting raptor, in French farmlands. We assess the effectiveness of alternative nest protection measures and map their potential benefit to the species. 3. We show that unprotected nests in cultivated land are strongly negatively affected by harvesting and thus require active management. Further, we show that protection from harvesting alone (e.g. by leaving a small unharvested buffer around the nest) is impaired by post-harvest predation at nests that become highly conspicuous after harvest. Measures that simultaneously protect from harvesting and predation (by adding a fence around the nest) significantly enhance nest productivity. 4. The map of expected gain from nest protection in relation to available volunteers' workforce pinpoints large areas of high expected gain from nest protection that are not matched by equally high workforce availability. This mismatch suggests that the impact of nest protection can be further improved by increasing volunteer efforts in key areas where they are low relative to the expected gain they could have. 5. Synthesis and applications . This study shows that synergistic interplay of multiple factors (e.g. mechanical harvesting and predation) may completely undermine the success of well-intentioned conservation efforts. However, identifying areas where the greatest expected gains can be achieved relative to effort expended can minimize the risk of wasted volunteer actions. Overall, this study underscores the importance of citizen science for collecting large-scale data useful for producing science and ultimately informs

Factors affecting nuclear development

International Nuclear Information System (INIS)

Stevens, G.H.; Girouard, P.

1995-01-01

Among the factors affecting nuclear development, some depend more or less on public authorities, but many are out of public authorities control (foreign policies, market and deregulation, socials and environmental impacts, public opinion). As far as possible, the following study tries to identify those factors. (D.L.). 2 photos

Factors affecting construction performance: exploratory factor analysis

Science.gov (United States)

Soewin, E.; Chinda, T.

2018-04-01

The present work attempts to develop a multidimensional performance evaluation framework for a construction company by considering all relevant measures of performance. Based on the previous studies, this study hypothesizes nine key factors, with a total of 57 associated items. The hypothesized factors, with their associated items, are then used to develop questionnaire survey to gather data. The exploratory factor analysis (EFA) was applied to the collected data which gave rise 10 factors with 57 items affecting construction performance. The findings further reveal that the items constituting ten key performance factors (KPIs) namely; 1) Time, 2) Cost, 3) Quality, 4) Safety & Health, 5) Internal Stakeholder, 6) External Stakeholder, 7) Client Satisfaction, 8) Financial Performance, 9) Environment, and 10) Information, Technology & Innovation. The analysis helps to develop multi-dimensional performance evaluation framework for an effective measurement of the construction performance. The 10 key performance factors can be broadly categorized into economic aspect, social aspect, environmental aspect, and technology aspects. It is important to understand a multi-dimension performance evaluation framework by including all key factors affecting the construction performance of a company, so that the management level can effectively plan to implement an effective performance development plan to match with the mission and vision of the company.

Pre-nesting and nesting behavior of the Swainson's warbler

Science.gov (United States)

Meanley, B.

1969-01-01

The Swainson?s Warbler is one of the least known of southern birds. Although fairly common in some parts of its summer range, observations of its breeding biology have been made by very few persons. The present study was conducted mostly at Macon, Georgia; Pendleton Ferry, Arkansas; and Dismal Swamp, Virginia....In central Georgia and east-central Arkansas, Swainson?s Warblers usually arrive on their territories during the first two weeks in April. Territories in several localities ranged in size from 0.3 to 4.8 acres. A color-marked Arkansas male occupied the same territory for at least four months. Hostile encounters between territorial male Swainson?s Warblers usually take place along the boundary of adjacent territories. Paired males were more aggressive than unpaired males. Toward the end of an encounter one of the two males would usually perform a display in which the wing and tail feathers were spread and the tail vibrated. Following boundary encounters males drifted back onto their territories and usually sang unbroken courses of songs for several minutes.....During pre-nesting at Macon, a mated pair spent the day mostly on the ground within 20 feet of each other, often foragin g 3 to 4 feet apart. What may have been a form of courtship display, in which the male flew from a perch down to the female and either pecked her rump or pounced on her, occurred about three times each hour throughout the day. During this period the male sang less than at other times during the breeding season.....First nests are usually built by the first week in May. Although other investigators reported finding nests of this species outside of the defended territory, all nests that I have found were within the territory. The large, bulky nest of this species usually is placed 2-6 feet above the ground. It is built by the female from materials gathered close to the nest site; and takes two or three days to complete.....Three and occasionally four white eggs are laid. The female

Open cup nests evolved from roofed nests in the early passerines.

Science.gov (United States)

Price, J Jordan; Griffith, Simon C

2017-02-08

The architectural diversity of nests in the passerine birds (order Passeriformes) is thought to have played an important role in the adaptive radiation of this group, which now comprises more than half of avian species and occupies nearly all terrestrial ecosystems. Here, we present an extensive survey and ancestral state reconstruction of nest design across the passerines, focusing on early Australian lineages and including members of nearly all passerine families worldwide. Most passerines build open cup-shaped nests, whereas a minority build more elaborate domed structures with roofs. We provide strong evidence that, despite their relative rarity today, domed nests were constructed by the common ancestor of all modern passerines. Open cup nests evolved from enclosed domes at least four times independently during early passerine evolution, at least three of which occurred on the Australian continent, yielding several primarily cup-nesting clades that are now widespread and numerically dominant among passerines. Our results show that the ubiquitous and relatively simple cup-shaped nests of many birds today evolved multiple times convergently, suggesting adaptive benefits over earlier roofed designs. © 2017 The Author(s).

Effects of human disturbance on nest placement of the woodpigeon (Columba palumbus): a case study from the Middle Atlas, Morocco.

Science.gov (United States)

Hanane, Saâd

2014-06-01

The woodpigeon (Columba palumbus) is a common and widespread bird in Morocco (North Africa). I examined, over 2 years (2010 and 2011), the breeding density and nest placement of this game species in relation to nest site habitat and degree of human disturbance. The study area was in the Middle Atlas Tighboula mountain forest, Morocco, in a disturbed and an undisturbed site. Using data collected in the 2 study sites, I aimed to identify the factors influencing the placement of nests within holm oak trees (Quercus rotundifolia) and their densities. I found that habitat structures, influenced by grazing disturbance, have affected nesting density and the location of nests of this species. Woodpigeons place their nests in a higher position (3.42 ± 0.19 m) when disturbance intensity is high and lower (1.68 ± 0.1 m) when disturbance intensity is low, and show higher nesting density in less disturbed zone (3.1 ± 0.4 nests/ha) than in highly disturbed zones (1.4 ± 0.2 nests/ha). Grazing disturbance could pose a threat to population persistence at a broader scale and could potentially reduce the abundance of this species by altering the composition and the structure of the forest nesting habitat. Further multi-scale studies are needed to assess the effects of different levels of grazing disturbance on woodpigeon nest density and placement, and to enhance our knowledge of the breeding behavior of this game species under variable environments. © 2013 International Society of Zoological Sciences, Institute of Zoology/Chinese Academy of Sciences and Wiley Publishing Asia Pty Ltd.

Do Predation Rates on Artificial Nests Accurately Reflect Predation Rates on Natural Bird Nests?

Science.gov (United States)

David I. King; Richard M. DeGraaf; Curtice R. Griffin; Thomas J. Maier

1999-01-01

Artificial nests are widely used in avian field studies. However, it is unclear how well predation rates on artificial nests reflect predation rates on natural nests. Therefore, we compared survival rates of artificial nests (unused natural nests baited with House Sparrow eggs) with survival rates of active bird nests in the same habitat at the same sites. Survival...

Factors Affecting Medical Service Quality.

Science.gov (United States)

Mosadeghrad, Ali Mohammad

2014-02-01

A better understanding of factors influencing quality of medical service can pinpoint better strategies for quality assurance in medical services. This study aimed to identify factors affecting the quality of medical services provided by Iranian physicians. Exploratory in-depth individual interviews were conducted with sixty-four physicians working in various medical institutions in Iran. Individual, organizational and environmental factors enhance or inhibit the quality of medical services. Quality of medical services depends on the personal factors of the physician and patient, and factors pertaining to the healthcare setting and the broader environment. Differences in internal and external factors such as availability of resources, patient cooperation and collaboration among providers affect the quality of medical services and patient outcomes. Supportive leadership, proper planning, education and training and effective management of resources and processes improve the quality of medical services. This article contributes to healthcare theory and practice by developing a conceptual framework for understanding factors that influence medical services quality.

Factors affecting hatch success of hawksbill sea turtles on Long Island, Antigua, West Indies.

Directory of Open Access Journals (Sweden)

Mark Allan Ditmer

Full Text Available Current understanding of the factors influencing hawksbill sea turtle (Eretmochelys imbricata hatch success is disparate and based on relatively short-term studies or limited sample sizes. Because global populations of hawksbills are heavily depleted, evaluating the parameters that impact hatch success is important to their conservation and recovery. Here, we use data collected by the Jumby Bay Hawksbill Project (JBHP to investigate hatch success. The JBHP implements saturation tagging protocols to study a hawksbill rookery in Antigua, West Indies. Habitat data, which reflect the varied nesting beaches, are collected at egg deposition, and nest contents are exhumed and categorized post-emergence. We analyzed hatch success using mixed-model analyses with explanatory and predictive datasets. We incorporated a random effect for turtle identity and evaluated environmental, temporal and individual-based reproductive variables. Hatch success averaged 78.6% (SD: 21.2% during the study period. Highly supported models included multiple covariates, including distance to vegetation, deposition date, individual intra-seasonal nest number, clutch size, organic content, and sand grain size. Nests located in open sand were predicted to produce 10.4 more viable hatchlings per clutch than nests located >1.5 m into vegetation. For an individual first nesting in early July, the fourth nest of the season yielded 13.2 more viable hatchlings than the initial clutch. Generalized beach section and inter-annual variation were also supported in our explanatory dataset, suggesting that gaps remain in our understanding of hatch success. Our findings illustrate that evaluating hatch success is a complex process, involving multiple environmental and individual variables. Although distance to vegetation and hatch success were inversely related, vegetation is an important component of hawksbill nesting habitat, and a more complete assessment of the impacts of specific

Examining the Factors Affecting Student Dropout

Directory of Open Access Journals (Sweden)

Fethi Ahmet INAN

2006-07-01

Full Text Available This study examined the factors affecting student dropouts in an online certificate program. In this research, a combination of quantitative and qualitative methods was used. Online Course Dropout Survey was developed and used to determine which factors affect student attrition from the program. The dropout survey was sent by e-mail to 98 students who had dropped the program. Twenty-six students returned the survey. The findings show that the most important factor affecting student retention is finding sufficient time to study. Having personal problems and affordability of the program took second and third place.

Physical cognition: birds learn the structural efficacy of nest material.

Science.gov (United States)

Bailey, Ida E; Morgan, Kate V; Bertin, Marion; Meddle, Simone L; Healy, Susan D

2014-06-07

It is generally assumed that birds' choice of structurally suitable materials for nest building is genetically predetermined. Here, we tested that assumption by investigating whether experience affected male zebra finches' (Taeniopygia guttata) choice of nest material. After a short period of building with relatively flexible string, birds preferred to build with stiffer string while those that had experienced a stiffer string were indifferent to string type. After building a complete nest with either string type, however, all birds increased their preference for stiff string. The stiffer string appeared to be the more effective building material as birds required fewer pieces of stiffer than flexible string to build a roofed nest. For birds that raised chicks successfully, there was no association between the material they used to build their nest and the type they subsequently preferred. Birds' material preference reflected neither the preference of their father nor of their siblings but juvenile experience of either string type increased their preference for stiffer string. Our results represent two important advances: (i) birds choose nest material based on the structural properties of the material; (ii) nest material preference is not entirely genetically predetermined as both the type and amount of experience influences birds' choices.

Nest fidelity is driven by multi-scale information in a long-lived seabird.

Science.gov (United States)

Robert, Alexandre; Paiva, Vítor H; Bolton, Mark; Jiguet, Frédéric; Bried, Joël

2014-10-22

Although the reproductive success of most organisms depends on factors acting at several spatial scales, little is known about how organisms are able to synthesize multi-scale information to optimize reproduction. Using longitudinal data from a long-lived seabird, Monteiro's storm-petrel, we show that average breeding success is strongly related to oceanic conditions at the population level, and we postulate that (i) individuals use proximal information (their own reproduction outcome in year t) to assess the qualities of their mate and nest and to decide to retain them or not in year t + 1; (ii) the intensity of these responses depends on the quality of the oceanic environment in year t, which affects the predictability of reproduction outcome in year t + 1. Our results confirm that mate and nest fidelities are higher following successful reproduction and that the relationship between the success of a given pair and subsequent nest fidelity is stronger in years with unfavourable oceanic conditions, suggesting that individuals rely on distant information to modulate their use of proximal information and adjust their breeding strategy. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

Nest structure and communal nesting in Euglossa (Glossura annectans Dressler (Hymenoptera, Apidae, Euglossini

Directory of Open Access Journals (Sweden)

Carlos Alberto Garófalo

1998-01-01

Full Text Available Three nests of Euglossa (Glossura annectans Dressier, 1982 were obtained from trap nests at Serra do Japi, Jundiai, São Paulo State, Brazil. The bees nested in bamboo cane (one nest and in wooden-boxes (two nests. Solitary (two cases and pleometrotic (one case foundations were observed. Two nests were re-used once by two females working in each of them. Re-using females that shared the nests were of the same generation and each built, provisioned and oviposited in her own cells, characterizing a communal association. The brood development period was related to climatic conditions. Natural enemies included Anthrax oedipus oedipus Fabricius, 1805 (Bombyliidae, Coelioxys sp. (Megachilidae and Melittobia sp. (Eulophidae.

Long-term lesser prairie-chicken nest ecology in response to grassland management

Science.gov (United States)

Fritts, Sarah R.; Grisham, Blake A.; Haukos, David A.; Boal, Clint W.; Patten, Michael; Wolfe, Don H.; Dixon, Charles; Cox, Robert D.; Heck, Willard R.

2016-01-01

Long-term population and range declines from habitat loss and fragmentation caused the lesser prairie-chicken (Tympanuchus pallidicinctus) to be a species of concern throughout its range. Current lesser prairie-chicken range in New Mexico and Texas is partially restricted to sand shinnery oak (Quercus havardii; hereafter shinnery oak) prairies, on which cattle grazing is the main socioeconomic driver for private landowners. Cattle producers within shinnery oak prairies often focus land management on shrub eradication using the herbicide tebuthiuron to promote grass production for forage; however, herbicide application alone, and in combination with grazing, may affect nest site selection and nest survival of lesser prairie-chickens through the reduction of shinnery oak and native grasses. We used a controlled, paired, completely randomized design study to assess the influence of grazing and tebuthiuron application and their combined use on nest site selection and nest survival from 2001 to 2010 in Roosevelt County, New Mexico, USA at 2 spatial scales (i.e., treatment and microhabitat) in 4 treatments: tebuthiuron with grazing, tebuthiuron without grazing, no tebuthiuron with grazing, and a control of no tebuthiuron and no grazing. Grazing treatment was a short-duration system in which plots were grazed once during the dormant season and once during the growing season. Stocking rate was calculated each season based on measured forage production and applied to remove ≤25% of available herbaceous material per season. At the treatment scale, we compared nest site selection among treatments using 1-way χ2 tests and nest survival among treatments using a priori candidate nest survival models in Program MARK. At the microhabitat scale, we identified important habitat predictors of nest site selection and nest survival using logistic regression and a priori candidate nest survival models in Program MARK, respectively. Females typically used treatments as expected and

Effect of heterogeneity of nest boxes on occurrence of gregarious nesting in laying hens

DEFF Research Database (Denmark)

Clausen, Tina; Riber, Anja Brinch

2012-01-01

Gregarious nesting, where hens select already occupied nest boxes even when other nest boxes are unoccupied, is an unwanted behaviour in laying hens that may reduce animal welfare and pose a financial cost to the producer. It has been suggested that gregarious nesting is caused by the difficulties...... nesting was higher in experimental groups compared to control groups (P right were higher compared to nest boxes positioned...

Nest building is a novel method for indexing severity of alcohol withdrawal in mice.

Science.gov (United States)

Greenberg, G D; Huang, L C; Spence, S E; Schlumbohm, J P; Metten, P; Ozburn, A R; Crabbe, J C

2016-04-01

Withdrawal after chronic ethanol (EtOH) affects body temperature, goal-directed behavior and motor function in mice and increases general central nervous system excitability. Nest-building tests have been used to assay these states but to this point have not been employed as measures of EtOH withdrawal severity. We first refined nest-scoring methods using a genetically heterogeneous stock of mice (HS/Npt). Mice were then made physically dependent following three days of chronic EtOH vapor inhalation to produce average blood EtOH concentrations (BECs) of 1.89 mg/mL. EtOH withdrawal affected the progression of nest building over time when mice were tested 2-4 days after removal from three days of chronic exposure to EtOH. In a separate group of mice, chronic EtOH vapor inhalation (BECs 1.84 mg/mL) suppressed nest building over days 1-2 but not days 2-3 of withdrawal. In a following experiment, EtOH withdrawal dose-dependently slowed recovery of nest building for up to 32 h. Finally, we determined that long-lasting nest-building deficits extend to mice undergoing withdrawal from a high dose (4 g/kg) of acute EtOH. Sex differences for nest building were absent following EtOH exposure. In mice naïve to EtOH treatments, male mice had lower pre-test body temperatures and increased nest scores across a two-day testing period compared to females. These results suggest that nest building can be used to assess chronic and acute EtOH withdrawal severity in mice. Published by Elsevier B.V.

Nesting behavior of Palila, as assessed from video recordings

Science.gov (United States)

Laut, M.E.; Banko, P.C.; Gray, E.M.

2003-01-01

We quantified nesting behavior of Palila (Loxiodes bailleui), an endangered Hawaiian honeycreeper, by recording at nests during three breeding seasons using a black-and-white video camera connected to a Videocassette recorder. A total of seven nests was observed. We measured the following factors for daylight hours: percentage of time the female was on the nest (attendance), length of attendance bouts by the female, length of nest recesses, and adult provisioning rates. Comparisons were made between three stages of the 40-day nesting cycle: incubation (day 1-day 16), early nestling stage (day 17-day 30 [i.e., nestlings ??? 14 days old]), and late nestling stage (day 31-day 40 [i.e., nestlings > 14 days old]). Of seven nests observed, four fledged at least one nestling and three failed. One of these failed nests was filmed being depredated by a feral cat (Felis catus). Female nest attendance was near 82% during the incubation stage and decreased to 21% as nestlings aged. We did not detect a difference in attendance bout length between stages of the nesting cycle. Mean length of nest recesses increased from 4.5 min during the incubation stage to over 45 min during the late nestling stage. Mean number of nest recesses per hour ranged from 1.6 to 2.0. Food was delivered to nestlings by adults an average of 1.8 times per hour for the early nestling stage and 1.5 times per hour during the late nestling stage and did not change over time. Characterization of parental behavior by video had similarities to but also key differences from findings taken from blind observations. Results from this study will facilitate greater understanding of Palila reproductive strategies.

Male Rock Sparrow (Petronia petronia) Nest Defence Correlates with Female Ornament Size

DEFF Research Database (Denmark)

Griggio, Matteo; Matessi, Giuliano; Pilastro, Andrea

2003-01-01

We investigated the relationship between male nest defence and female breast patch size in an alpine population of rock sparrow (Petronia petronia) in northern Italy. We presented a mounted weasel (Mustela nivalis), a common nest predator, to 28 pairs breeding in nest boxes, with 12-13-d-old nest......We investigated the relationship between male nest defence and female breast patch size in an alpine population of rock sparrow (Petronia petronia) in northern Italy. We presented a mounted weasel (Mustela nivalis), a common nest predator, to 28 pairs breeding in nest boxes, with 12-13-d...... defence factor was significantly related only to female breast patch size. We argue that male rock sparrows apparently make parental investment decisions according to their mate's quality, and examine possible alternative hypotheses....

Factors affecting reed warbler risk of brood parasitism by the common cuckoo

Czech Academy of Sciences Publication Activity Database

Clarke, A. L.; Oien, I. J.; Honza, Marcel; Moksnes, A.; Roskaft, E.

2001-01-01

Roč. 118, č. 2 (2001), s. 534-538 ISSN 0004-8038 R&D Projects: GA ČR GA206/97/0168 Institutional research plan: CEZ:AV0Z6093917 Keywords : Cuculus canorus * nests Subject RIV: EG - Zoology Impact factor: 1.379, year: 2001 http://www.jstor.org/stable/4089817

Nest predation increases with parental activity: separating nest site and parental activity effects.

OpenAIRE

Martin, T E; Scott, J; Menge, C

2000-01-01

Alexander Skutch hypothesized that increased parental activity can increase the risk of nest predation. We tested this hypothesis using ten open-nesting bird species in Arizona, USA. Parental activity was greater during the nestling than incubation stage because parents visited the nest frequently to feed their young during the nestling stage. However, nest predation did not generally increase with parental activity between nesting stages across the ten study species. Previous investigators h...

Spatial structure and nest demography reveal the influence of competition, parasitism and habitat quality on slavemaking ants and their hosts.

Science.gov (United States)

Scharf, Inon; Fischer-Blass, Birgit; Foitzik, Susanne

2011-03-28

Natural communities are structured by intra-guild competition, predation or parasitism and the abiotic environment. We studied the relative importance of these factors in two host-social parasite ecosystems in three ant communities in Europe (Bavaria) and North America (New York, West Virginia). We tested how these factors affect colony demography, life-history and the spatial pattern of colonies, using a large sample size of more than 1000 colonies. The strength of competition was measured by the distance to the nearest competitor. Distance to the closest social parasite colony was used as a measure of parasitism risk. Nest sites (i.e., sticks or acorns) are limited in these forest ecosystems and we therefore included nest site quality as an abiotic factor in the analysis. In contrast to previous studies based on local densities, we focus here on the positioning and spatial patterns and we use models to compare our predictions to random expectations. Colony demography was universally affected by the size of the nest site with larger and more productive colonies residing in larger nest sites of higher quality. Distance to the nearest competitor negatively influenced host demography and brood production in the Bavarian community, pointing to an important role of competition, while social parasitism was less influential in this community. The New York community was characterized by the highest habitat variability, and productive colonies were clustered in sites of higher quality. Colonies were clumped on finer spatial scales, when we considered only the nearest neighbors, but more regularly distributed on coarser scales. The analysis of spatial positioning within plots often produced different results compared to those based on colony densities. For example, while host and slavemaker densities are often positively correlated, slavemakers do not nest closer to potential host colonies than expected by random. The three communities are differently affected by biotic and

Spatial structure and nest demography reveal the influence of competition, parasitism and habitat quality on slavemaking ants and their hosts

Directory of Open Access Journals (Sweden)

Fischer-Blass Birgit

2011-03-01

Full Text Available Abstract Background Natural communities are structured by intra-guild competition, predation or parasitism and the abiotic environment. We studied the relative importance of these factors in two host-social parasite ecosystems in three ant communities in Europe (Bavaria and North America (New York, West Virginia. We tested how these factors affect colony demography, life-history and the spatial pattern of colonies, using a large sample size of more than 1000 colonies. The strength of competition was measured by the distance to the nearest competitor. Distance to the closest social parasite colony was used as a measure of parasitism risk. Nest sites (i.e., sticks or acorns are limited in these forest ecosystems and we therefore included nest site quality as an abiotic factor in the analysis. In contrast to previous studies based on local densities, we focus here on the positioning and spatial patterns and we use models to compare our predictions to random expectations. Results Colony demography was universally affected by the size of the nest site with larger and more productive colonies residing in larger nest sites of higher quality. Distance to the nearest competitor negatively influenced host demography and brood production in the Bavarian community, pointing to an important role of competition, while social parasitism was less influential in this community. The New York community was characterized by the highest habitat variability, and productive colonies were clustered in sites of higher quality. Colonies were clumped on finer spatial scales, when we considered only the nearest neighbors, but more regularly distributed on coarser scales. The analysis of spatial positioning within plots often produced different results compared to those based on colony densities. For example, while host and slavemaker densities are often positively correlated, slavemakers do not nest closer to potential host colonies than expected by random. Conclusions The

Phenology largely explains taller grass at successful nests in greater sage-grouse.

Science.gov (United States)

Smith, Joseph T; Tack, Jason D; Doherty, Kevin E; Allred, Brady W; Maestas, Jeremy D; Berkeley, Lorelle I; Dettenmaier, Seth J; Messmer, Terry A; Naugle, David E

2018-01-01

Much interest lies in the identification of manageable habitat variables that affect key vital rates for species of concern. For ground-nesting birds, vegetation surrounding the nest may play an important role in mediating nest success by providing concealment from predators. Height of grasses surrounding the nest is thought to be a driver of nest survival in greater sage-grouse ( Centrocercus urophasianus ; sage-grouse), a species that has experienced widespread population declines throughout their range. However, a growing body of the literature has found that widely used field methods can produce misleading inference on the relationship between grass height and nest success. Specifically, it has been demonstrated that measuring concealment following nest fate (failure or hatch) introduces a temporal bias whereby successful nests are measured later in the season, on average, than failed nests. This sampling bias can produce inference suggesting a positive effect of grass height on nest survival, though the relationship arises due to the confounding effect of plant phenology, not an effect on predation risk. To test the generality of this finding for sage-grouse, we reanalyzed existing datasets comprising >800 sage-grouse nests from three independent studies across the range where there was a positive relationship found between grass height and nest survival, including two using methods now known to be biased. Correcting for phenology produced equivocal relationships between grass height and sage-grouse nest survival. Viewed in total, evidence for a ubiquitous biological effect of grass height on sage-grouse nest success across time and space is lacking. In light of these findings, a reevaluation of land management guidelines emphasizing specific grass height targets to promote nest success may be merited.

Changing nest placement of Hawaiian Common Amakihi during the breeding cycle

Science.gov (United States)

van Riper, Charles; Kern, M. D.; Sogge, M. K.

1993-01-01

We studied the nesting behavior of the Common Amakihi (Hemignathus virens) from 1970-1981 on the island of Hawaii to determine if the species alters nest placement over a protracted 9-month breeding season. Birds preferentially chose the southwest quadrant of trees in which to build nests during all phases of the breeding season. It appeared that ambient temperature (Ta) was a contributing factor to differential nest placement between early and late phases of the annual breeding cycle. When Ta is low during the early (December-March) breeding period, Common Amakihi selected exposed nesting locations that benefitted them with maximum solar insolation. However, in the later phase of the breeding period (April-July) when Ta was much higher, renesting birds selected nest sites deeper in the canopy in significantly taller trees. This is one of the few documented examples in which a species changes location of nest during a breeding season, thus allowing exploitation of temporally differing microclimatic conditions.

The nest as fortress: Defensive behavior of Polybia emaciata, a mud-nesting eusocial wasp

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Sean O'Donnell

2002-02-01

Full Text Available The swarm-founding wasp Polybia emaciata is unusual among eusocial Vespidae because it uses mud, rather than wood pulp, as its primary nest construction material. Polybia emaciata nests are more durable than similarly sized paper nests. We tested the hypothesis that the defensive behavior of this wasp may have been modified to take advantage of their strong nests in defense against vertebrate attacks. We simulated vertebrate disturbances by tapping on, and breathing in, P. emaciata. nests and similarly sized P. occidentalis paper nests in the same location at the same time. Polybia emaciata. responses to disturbance were qualitatively different from those of P. occidentalis. The latter exit the nest and attack, while P. emaciata. workers typically fled or entered the nest, attacking only after repeated and extended disturbances. We conclude that durable nest material may permit predator avoidance behavior in P. emaciata.. We compare the defensive responses of P. emaciata. workers with those of other swarm-founding Vespidae, and discuss several selective forces that could cause the evolution of species variation in nest defense behavior.

Cavity Nesting Birds

Science.gov (United States)

Virgil E. Scott; Keith E. Evans; David R. Patton; Charles P. Stone

1977-01-01

Many species of cavity-nesting birds have declined because of habitat reduction. In the eastern United States, where primeval forests are gone, purple martins depend almost entirely on man-made nesting structures (Allen and Nice 1952). The hole-nesting population of peregrine falcons disappeared with the felling of the giant trees upon which they depended (Hickey and...

Nest predators of open and cavity nesting birds in oak woodlands

Science.gov (United States)

Kathryn L. Purcell; Jared Verner

1999-01-01

Camera setups revealed at least three species of rodents and seven species of birds as potential predators at artificial open nests. Surprisingly, among avian predators identified at open nests, one third were Bullock's Orioles (Icterus bullockii). Two rodent species and three bird species were potential predators at artificial cavity nests. This high predator...

Lifespan analyses of forest raptor nests: patterns of creation, persistence and reuse.

Directory of Open Access Journals (Sweden)

María V Jiménez-Franco

Full Text Available Structural elements for breeding such as nests are key resources for the conservation of bird populations. This is especially true when structural elements require a specific and restricted habitat, or if the construction of nests is costly in time and energy. The availability of nesting-platforms is influenced by nest creation and persistence. In a Mediterranean forest in southeastern Spain, nesting-platforms are the only structural element for three forest-dwelling raptor species: booted eagle Aquila pennata, common buzzard Buteo buteo and northern goshawk Accipiter gentilis. From 1998 to 2013, we tracked the fate of 157 nesting-platforms built and reused by these species with the aim of determining the rates of creation and destruction of nesting-platforms, estimating nest persistence by applying two survival analyses, describing the pattern of nest reuse and testing the effects of nest use on breeding success. Nest creation and destruction rates were low (0.14 and 0.05, respectively. Using Kaplan Meier survival estimates and Cox proportional-hazards regression models we found that median nest longevity was 12 years and that this was not significantly affected by nest characteristics, nest-tree dimensions, nest-builder species, or frequency of use of the platform. We also estimated a transition matrix, considering the different stages of nest occupation (vacant or occupied by one of the focal species, to obtain the fundamental matrix and the average life expectancies of nests, which varied from 17.9 to 19.7 years. Eighty six percent of nests were used in at least one breeding attempt, 67.5% were reused and 17.8% were successively occupied by at least two of the study species. The frequency of nest use had no significant effects on the breeding success of any species. We conclude that nesting-platforms constitute an important resource for forest raptors and that their longevity is sufficiently high to allow their reuse in multiple breeding

Lifespan Analyses of Forest Raptor Nests: Patterns of Creation, Persistence and Reuse

Science.gov (United States)

Jiménez-Franco, María V.; Martínez, José E.; Calvo, José F.

2014-01-01

Structural elements for breeding such as nests are key resources for the conservation of bird populations. This is especially true when structural elements require a specific and restricted habitat, or if the construction of nests is costly in time and energy. The availability of nesting-platforms is influenced by nest creation and persistence. In a Mediterranean forest in southeastern Spain, nesting-platforms are the only structural element for three forest-dwelling raptor species: booted eagle Aquila pennata, common buzzard Buteo buteo and northern goshawk Accipiter gentilis. From 1998 to 2013, we tracked the fate of 157 nesting-platforms built and reused by these species with the aim of determining the rates of creation and destruction of nesting-platforms, estimating nest persistence by applying two survival analyses, describing the pattern of nest reuse and testing the effects of nest use on breeding success. Nest creation and destruction rates were low (0.14 and 0.05, respectively). Using Kaplan Meier survival estimates and Cox proportional-hazards regression models we found that median nest longevity was 12 years and that this was not significantly affected by nest characteristics, nest-tree dimensions, nest-builder species, or frequency of use of the platform. We also estimated a transition matrix, considering the different stages of nest occupation (vacant or occupied by one of the focal species), to obtain the fundamental matrix and the average life expectancies of nests, which varied from 17.9 to 19.7 years. Eighty six percent of nests were used in at least one breeding attempt, 67.5% were reused and 17.8% were successively occupied by at least two of the study species. The frequency of nest use had no significant effects on the breeding success of any species. We conclude that nesting-platforms constitute an important resource for forest raptors and that their longevity is sufficiently high to allow their reuse in multiple breeding attempts. PMID

Survival during the Breeding Season: Nest Stage, Parental Sex, and Season Advancement Affect Reed Warbler Survival.

Directory of Open Access Journals (Sweden)

Kaja Wierucka

Full Text Available Avian annual survival has received much attention, yet little is known about seasonal patterns in survival, especially of migratory passerines. In order to evaluate survival rates and timing of mortality within the breeding season of adult reed warblers (Acrocephalus scirpaceus, mark-recapture data were collected in southwest Poland, between 2006 and 2012. A total of 612 individuals (304 females and 308 males were monitored throughout the entire breeding season, and their capture-recapture histories were used to model survival rates. Males showed higher survival during the breeding season (0.985, 95% CI: 0.941-0.996 than females (0.869, 95% CI: 0.727-0.937. Survival rates of females declined with the progression of the breeding season (from May to August, while males showed constant survival during this period. We also found a clear pattern within the female (but not male nesting cycle: survival was significantly lower during the laying, incubation, and nestling periods (0.934, 95% CI: 0.898-0.958, when birds spent much time on the nest, compared to the nest building and fledgling periods (1.000, 95% CI: 1.00-1.000, when we did not record any female mortality. These data (coupled with some direct evidence, like bird corpses or blood remains found next to/on the nest may suggest that the main cause of adult mortality was on-nest predation. The calculated survival rates for both sexes during the breeding season were high compared to annual rates reported for this species, suggesting that a majority of mortality occurs at other times of the year, during migration or wintering. These results have implications for understanding survival variation within the reproductive period as well as general trends of avian mortality.

Modeling nest survival of cavity-nesting birds in relation to postfire salvage logging

Science.gov (United States)

Vicki Saab; Robin E. Russell; Jay Rotella; Jonathan G. Dudley

2011-01-01

Salvage logging practices in recently burned forests often have direct effects on species associated with dead trees, particularly cavity-nesting birds. As such, evaluation of postfire management practices on nest survival rates of cavity nesters is necessary for determining conservation strategies. We monitored 1,797 nests of 6 cavity-nesting bird species: Lewis'...

Hypoxia increases the risk of egg predation in a nest-guarding fish

DEFF Research Database (Denmark)

Olsson, Karin; Kvarnemo, Charlotta; Andrén, Maria Norevik

2016-01-01

For fish with parental care, a nest should meet both the oxygenation needs of the eggs and help protect them against predators. While a small nest opening facilitates the latter, it impedes the former and vice versa. We investigated how the presence of potential egg predators in the form of shore...... in high oxygen reduced fanning, males in low oxygen did not. Filial cannibalism was unaffected by treatment. Sand gobies thus prioritize egg ventilation over the protection afforded by small nest openings under hypoxia and adopt defensive behaviour to avert predator attention, even though this does...... crabs Carcinus maenas affects nest building, egg fanning, defensive displays and filial cannibalism of egg-guarding male sand gobies Pomatoschistus minutus under two levels of dissolved oxygen. In the high oxygen treatment, males retained their nest opening size in the presence of crabs, while males...

Triangular Nests!

Science.gov (United States)

Powell, R. I.

2002-01-01

Shows how integer-sided triangles can be nested, each nest having a single enclosing isosceles triangle. Brings to light what can be seen as a relatively simple generalization of Pythagoras' theorem, a result that should be readily accessible to many secondary school pupils. (Author/KHR)

Cavity-nesting bird use of nest boxes in vineyards of central-coast California

Science.gov (United States)

Daniel P. Mummert; Laura Baines; William D. Tietje

2002-01-01

Oak woodland habitat is being degraded or replaced by vineyards in many areas of central-coastal California. Oak woodlands are home to many insectivorous, cavity-nesting birds that would be beneficial in and around vineyards. During March to June 2001, we used bluebird nest boxes to study nest box use and productivity of cavity-nesting birds in vineyards versus...

Age and breeding success related to nest position in a White stork Ciconia ciconia colony

Science.gov (United States)

Vergara, Pablo; Aguirre, José I.

2006-11-01

Coloniality is a breeding system that may produce benefits in terms of breeding success, although these advantages could vary according to factors such as colony size or nest position. We studied breeder's age in relation to nest position (peripheral or central) within the colony. In addition, we studied the relationship between breeding success and nest position, controlling for breeder's age, a highly correlated factor, in a White Stork Ciconia ciconia colony over a 7-year period. Our results show that central nests are mainly occupied by adult birds and had lower failure rates. However, controlling for breeder's age, nest position per se did not explain breeding success. The scarce predation and the lack of human disturbance in the study colony could explain the absence of differences in breeding success between different nest positions within the colony.

Livestock grazing and trampling of birds' nests: An experiment using artificial nests

OpenAIRE

Mandema, Freek S.; Tinbergen, Joost M.; Ens, Bruno J.; Bakker, Jan P.

2013-01-01

The purpose of this study is to experimentally determine the differences between four grazing treatments on the trampling of nests. Additionally, we examine to what extent the trampling probability of nests is higher close to a source of fresh water. We compare the trampling of artificial nests in five different grazing treatments in an experimental design. We use buried clay pigeon targets as artificial mimics of bird nests to obtain reliable estimates of trampling risk and compare these wit...

Flown The Nest

OpenAIRE

Sebbane, Nathalie

2012-01-01

Lorsque le quotidien régional, The Champion, commence à publier Flown The Nest en 1972 sous forme d’épisodes, Bird’s Nest Soup est déjà en vente, et la troisième partie de l’autobiographie d’Hanna, Housekeeper At Large, est sous presse. L’édition de 2009 contient Flown The Nest et Housekeeper at Large. Dans Bird’s Nest Soup, Hanna Greally racontait les dix-huit années de sa vie passées au sein d’un hôpital psychiatrique. Les raisons pour lesquelles elle y avait été enfermée, à la demande de s...

Identification of Environmental Factors Associated with Inflammatory Bowel Disease in a Southwestern Highland Region of China: A Nested Case-Control Study.

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Junkun Niu

Full Text Available The aim of this study was to examine environmental factors associated with inflammatory bowel disease (IBD in Yunnan Province, a southwestern highland region of China.In this nested case-control study, newly diagnosed ulcerative colitis (UC cases in 2 cities in Yunnan Province and Crohn's disease (CD cases in 16 cities in Yunnan Province were recruited between 2008 and 2013. Controls were matched by geography, sex and age at a ratio of 1:4. Data were collected using the designed questionnaire. Conditional logistic regression models were used to estimate adjusted odds ratios (ORs.A total of 678 UC and 102 CD cases were recruited. For UC, various factors were associated with an increased risk of developing UC: dietary habits, including frequent irregular meal times; consumption of fried foods, salty foods and frozen dinners; childhood factors, including intestinal infectious diseases and frequent use of antibiotics; and other factors, such as mental labor, high work stress, use of non-aspirin non-steroidal anti-inflammatory drugs and allergies (OR > 1, p 1, p < 0.05, whereas physical activity may have reduced this risk (OR < 1, p < 0.05.This study is the first nested case-control study to analyze the association between environmental factors and IBD onset in a southwestern highland region of China. Certain dietary habits, lifestyles, allergies and childhood factors may play important roles in IBD, particularly UC.

Low Calorie Diet Affects Aging-Related Factors

Science.gov (United States)

... Current Issue Past Issues Research News From NIH Low Calorie Diet Affects Aging-Related Factors Past Issues / ... to learn more about the effects of sustained low-calorie diets in humans on factors affecting aging. ...

The Rules of Aggression: How Genetic, Chemical and Spatial Factors Affect Intercolony Fights in a Dominant Species, the Mediterranean Acrobat Ant Crematogaster scutellaris.

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Filippo Frizzi

Full Text Available Nest-mate recognition plays a key role in the biology of ants. Although individuals coming from a foreign nest are, in most cases, promptly rejected, the degree of aggressiveness towards non nest-mates may be highly variable among species and relies on genetic, chemical and environmental factors. We analyzed intraspecific relationships among neighboring colonies of the dominant Mediterranean acrobat ant Crematogaster scutellaris integrating genetic, chemical and behavioral analyses. Colony structure, parental relationships between nests, cuticular hydrocarbons profiles (CHCs and aggressive behavior against non nest-mates were studied in 34 nests located in olive tree trunks. Bayesian clustering analysis of allelic variation at nine species-specific microsatellite DNA markers pooled nests into 14 distinct clusters, each representing a single colony, confirming a polydomous arrangement of nests in this species. A marked genetic separation among colonies was also detected, probably due to long distance dispersion of queens and males during nuptial flights. CHCs profiles varied significantly among colonies and between nests of the same colony. No relationship between CHCs profiles and genetic distances was detected. The level of aggressiveness between colonies was inversely related to chemical and spatial distance, suggesting a 'nasty neighbor' effect. Our findings also suggest that CHCs profiles in C. scutellaris may be linked to external environmental factors rather than genetic relationships.

From neurons to nests: nest-building behaviour as a model in behavioural and comparative neuroscience.

Science.gov (United States)

Hall, Zachary J; Meddle, Simone L; Healy, Susan D

Despite centuries of observing the nest building of most extant bird species, we know surprisingly little about how birds build nests and, specifically, how the avian brain controls nest building. Here, we argue that nest building in birds may be a useful model behaviour in which to study how the brain controls behaviour. Specifically, we argue that nest building as a behavioural model provides a unique opportunity to study not only the mechanisms through which the brain controls behaviour within individuals of a single species but also how evolution may have shaped the brain to produce interspecific variation in nest-building behaviour. In this review, we outline the questions in both behavioural and comparative neuroscience that nest building could be used to address, summarize recent findings regarding the neurobiology of nest building in lab-reared zebra finches and across species building different nest structures, and suggest some future directions for the neurobiology of nest building.

Avoiding the nest : responses of field sparrows to the threat of nest predation

Science.gov (United States)

Dirk E. Burhans

2000-01-01

Nest predation is a major source of reproductive failure in birds (Ricklefs 1969, Martin 1992). Birds confronted with an enemy near the nest may use behaviors to deter the prospect of nest predation. The benefits of nest defense have been shown for many agressive species (Martin 1992), but smaller birds that cannot deter predators may need to resort to other behaviors...

Influence of Nest Box Color and Release Sites on Osmia lignaria (Hymenoptera: Megachilidae) Reproductive Success in a Commercial Almond Orchard.

Science.gov (United States)

Artz, Derek R; Allan, Matthew J; Wardell, Gordon I; Pitts-Singer, Theresa L

2014-12-01

Intensively managed, commercial orchards offer resources for managed solitary bees within agricultural landscapes and provide a means to study bee dispersal patterns, spatial movement, nest establishment, and reproduction. In 2012, we studied the impact of 1) the color of nest boxes covaried with four nest box density treatments and 2) the number of bee release sites covaried with two nest box density treatments on the reproductive success of Osmia lignaria Say in a California almond orchard pollinated by a mixture of O. lignaria and Apis mellifera L. Nest box color influenced the number of nests, total cells, and cells with male and female brood. More nests and cells were produced in light blue nest boxes than in orange or yellow nest boxes. The covariate nest box density also had a significant effect on brood production. The number of release sites did not affect O. lignaria nesting and reproduction, but the number of cavities in nest boxes influenced reproduction. Overall, the color of nest boxes and their distribution, but not the number of release sites, can greatly affect O. lignaria nest establishment and reproductive success in a commercial almond orchard. The ability to locate nesting sites in a homogenous, large orchard landscape may also be facilitated by the higher frequency of nest boxes with low numbers of cavities, and by the ability to detect certain nest box colors that best contrast with the blooming trees. © 2014 Entomological Society of America.

No evidence for UV-based nest-site selection in sticklebacks

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Bakker Theo CM

2006-11-01

Full Text Available Abstract Background Nests are built in various animal taxa including fish. In systems with exclusive male parental care, the choice of a nest site may be an important component of male fitness. The nest site may influence male attractiveness as a mate, and male, embryo, and juvenile survival probabilities. Reproductively active three-spined stickleback males establish and defend a territory in which they build a nest. Territories can differ remarkably in qualities that influence male and female reproductive success like predation risk or abiotic factors such as dissolved oxygen concentration or lighting conditions. The latter may be important because in sticklebacks the extended visual capability into the ultraviolet (UV wave range plays a role in female mate choice. Males are thus expected to be choosy about the habitat in which they will build their nest. Results We tested nest-site choice in male three-spined sticklebacks with respect to different UV lighting conditions. Reproductively active males were given the simultaneous choice to build their nest either in an UV-rich (UV+ or an UV-lacking (UV- environment. Males exhibited no significant nest-site preferences with respect to UV+ or UV-. However, larger males and also heavier ones completed their nests earlier. Conclusion We found that UV radiation as well as differences in luminance had no influence on nest-site choice in three-spined sticklebacks. Males that built in the UV-rich environment were not different in any trait (body traits and UV reflection traits from males that built in the UV-poor environment. There was a significant effect of standard length and body mass on the time elapsed until nest completion in the UV experiment. The larger and heavier a male, the faster he completed his nest. In the brightness control experiment there was a significant effect only of body mass on the duration of nest completion. Whether nest building preferences with respect to UV lighting

Livestock grazing and trampling of birds' nests : An experiment using artificial nests

NARCIS (Netherlands)

Mandema, Freek S.; Tinbergen, Joost M.; Ens, Bruno J.; Bakker, Jan P.

The purpose of this study is to experimentally determine the differences between four grazing treatments on the trampling of nests. Additionally, we examine to what extent the trampling probability of nests is higher close to a source of fresh water. We compare the trampling of artificial nests in

Nested and Hierarchical Archimax copulas

KAUST Repository

Hofert, Marius

2017-07-03

The class of Archimax copulas is generalized to nested and hierarchical Archimax copulas in several ways. First, nested extreme-value copulas or nested stable tail dependence functions are introduced to construct nested Archimax copulas based on a single frailty variable. Second, a hierarchical construction of d-norm generators is presented to construct hierarchical stable tail dependence functions and thus hierarchical extreme-value copulas. Moreover, one can, by itself or additionally, introduce nested frailties to extend Archimax copulas to nested Archimax copulas in a similar way as nested Archimedean copulas extend Archimedean copulas. Further results include a general formula for the density of Archimax copulas.

Nested and Hierarchical Archimax copulas

KAUST Repository

Hofert, Marius; Huser, Raphaë l; Prasad, Avinash

2017-01-01

The class of Archimax copulas is generalized to nested and hierarchical Archimax copulas in several ways. First, nested extreme-value copulas or nested stable tail dependence functions are introduced to construct nested Archimax copulas based on a single frailty variable. Second, a hierarchical construction of d-norm generators is presented to construct hierarchical stable tail dependence functions and thus hierarchical extreme-value copulas. Moreover, one can, by itself or additionally, introduce nested frailties to extend Archimax copulas to nested Archimax copulas in a similar way as nested Archimedean copulas extend Archimedean copulas. Further results include a general formula for the density of Archimax copulas.

Nest site characteristics, nesting movements, and lack of long-term nest site fidelity in Agassiz's desert tortoises at a wind energy facility in southern California

Science.gov (United States)

Lovich, Jeffrey E.; Agha, Mickey; Yackulic, Charles B.; Meyer-Wilkins, Kathie; Bjurlin, Curtis; Ennen, Joshua R.; Arundel, Terry R.; Austin, Meaghan

2014-01-01

Nest site selection has important consequences for maternal and offspring survival and fitness. Females of some species return to the same nesting areas year after year. We studied nest site characteristics, fidelity, and daily pre-nesting movements in a population of Agassiz’s desert tortoises (Gopherus agassizii) at a wind energy facility in southern California during two field seasons separated by over a decade. No females returned to the same exact nest site within or between years but several nested in the same general area. However, distances between first and second clutches within a year (2000) were not significantly different from distances between nests among years (2000 and 2011) for a small sample of females, suggesting some degree of fidelity within their normal activity areas. Environmental attributes of nest sites did not differ significantly among females but did among years due largely to changes in perennial plant structure as a result of multiple fires. Daily pre-nesting distances moved by females decreased consistently from the time shelled eggs were first visible in X-radiographs until oviposition, again suggesting some degree of nest site selection. Tortoises appear to select nest sites that are within their long-term activity areas, inside the climate-moderated confines of one of their self-constructed burrows, and specifically, at a depth in the burrow that minimizes exposure of eggs and embryos to lethal incubation temperatures. Nesting in “climate-controlled” burrows and nest guarding by females relaxes some of the constraints that drive nest site selection in other oviparous species.

Nesting habitat use by river chubs in a hydrologically variable Appalachian tailwater

Energy Technology Data Exchange (ETDEWEB)

Peoples, Brandon K. [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States); McManamay, Ryan A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Orth, Donald J. [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States); Frimpong, Emmanuel A. [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States)

2013-07-02

Hydrologic alteration continues to affect aquatic biodiversity asknowledge of the spawning requirements of fishes, especially keystone or foundation species, becomes more critical for conservation and management. Our objectives are to quantify the spawning micro- and mesohabitat use of river chub Nocomis micropogon, a gravel mound nesting minnow, in a hydrologically regulated river in North Carolina, USA. At the microhabitat scale, substrate sizes on nests were compared with pebble counts in 1-m2 adjacent quadrats. Average depths and current velocities at nests were compared with measurements from paired transects. At the mesohabitat scale, generalised linear mixed models (GLMMs) were used to identify the importance of average bed slope, average depth and percentages of rock outcrops (a measure of flow heterogeneity and velocity shelters) for predicting nest presence and abundance. To relate nesting activities to hydrologic alteration from dam operation, nest dimensions were measured before and after a scheduled discharge event approximately six times that of base flow. In addition, linear regression was used to predict changes in the use of flow refugia and overhead cover with increased fluvial distance from the dam. Microhabitats in which nests were placed had, on average, slower current velocities and shallower depths. Gravel diameters of nests were significantly smaller than substrate particles adjacent to nests. GLMMs revealed that mesohabitats with nests were shallower, had more moderate slopes and greater proportions of rock outcrops than mesohabitats without nests. Finally, the scheduled discharge event significantly flattened nests. Near the dam, nests were built in close proximity ( 2 m) to velocity shelters; this relationship diminished with distance from the dam. River chubs are spawning habitat specialists. Because multiple species rely on river chub nests for reproduction and food, the needs of this species should be considered when managing instream

Nest site attributes and temporal patterns of northern flicker nest loss: effects of predation and competition.

Science.gov (United States)

Fisher, Ryan J; Wiebe, Karen L

2006-04-01

To date, most studies of nest site selection have failed to take into account more than one source of nest loss (or have combined all sources in one analysis) when examining nest site characteristics, leaving us with an incomplete understanding of the potential trade-offs that individuals may face when selecting a nest site. Our objectives were to determine whether northern flickers (Colaptes auratus) may experience a trade-off in nest site selection in response to mammalian nest predation and nest loss to a cavity nest competitor (European starling, Sturnus vulgaris). We also document within-season temporal patterns of these two sources of nest loss with the hypothesis that flickers may also be constrained in the timing of reproduction under both predatory and competitive influence. Mammalian predators frequently depredated flicker nests that were: lower to the ground, less concealed by vegetation around the cavity entrance and at the base of the nest tree, closer to coniferous forest edges and in forest clumps with a high percentage of conifer content. Proximity to coniferous edges or coniferous trees increased the probability of nest predation, but nests near conifers were less likely to be lost to starlings. Flickers may thus face a trade-off in nest site selection with respect to safety from predators or competitors. Models suggested that peaks of nest predation and nest loss to eviction occurred at the same time, although a competing model suggested that the peak of nest loss to starlings occurred 5 days earlier than the peak of mammalian predation. Differences in peaks of mammalian predation and loss to starlings may constrain any adjustment in clutch initiation date by flickers to avoid one source of nest loss.

Variation in nesting behavior of eight species of spider mites, Stigmaeopsis having sociality

Science.gov (United States)

Saito, Yutaka; Zhang, Yan-Xuan; Mori, Kotaro; Ito, Katsura; Sato, Yukie; Chittenden, Anthony R.; Lin, Jian-Zhen; Chae, Younghae; Sakagami, Takane; Sahara, Ken

2016-10-01

Nesting behavior is considered to be an important element of social living in animals. The spider mites belonging to the genus Stigmaeopsis spend their lives within nests produced from silk threads. Several of these species show cooperative sociality, while the others are subsocial. In order to identify the origins of this social behavior, comparisons of nest sizes, nesting behaviors (making nests continuously or separately), and their associated traits (fecal deposition patterns) were made for eight cogeneric Stigmaeopsis species showing various levels of social development. All of these species inhabit bamboo plants (Poaceae). We initially addressed the proximate factor of nest size variation. The variation in nest size of the eight species corresponded well with the variation in dorsal seta sc1 length, suggesting that nest size variation among species may have a genetic basis. The time spent within a nest (nest duration) increased with nest size on the respective host plants. Nest arrangement patterns varied among species showing different sized nests: Large nest builders continuously extended their nests, while middle and small nest-building species built new separate nests, which resulted in different social interaction times among species, and is thought to be closely related to social development. Fecal deposition behaviors also varied among Stigmaeopsis species, suggesting diversity in anti-predatory adaptations. Finally, we discuss how the variation in sociality observed within this genus is likely the result of nest size variation that initially evolved as anti-predator strategies.

Factors Affecting University Library Website Design

Directory of Open Access Journals (Sweden)

Yongi-Mi Kim

2011-09-01

Full Text Available Existing studies have extensively explored factors that affect users’ intentions to use university library website resources (ULWR; yet little attention has been given to factors affecting university library website design. This paper investigates factors that affect university library website design and assesses the success of the university library website from both designers’ and users’ perspectives. The findings show that when planning a website, university web designers consider university guidelines, review other websites, and consult with experts and other divisions within the library; however, resources and training for the design process are lacking. While website designers assess their websites as highly successful, user evaluations are somewhat lower. Accordingly, use is low, and users rely heavily on commercial websites. Suggestions for enhancing the usage of ULWR are provided.

Sandhill crane abundance and nesting ecology at Grays Lake, Idaho

Science.gov (United States)

Austin, J.E.; Henry, A.R.; Ball, I.J.

2007-01-01

We examined population size and factors influencing nest survival of greater sandhill cranes (Grus canadensis tabida) at Grays Lake National Wildlife Refuge, Idaho, USA, during 1997-2000. Average local population of cranes from late April to early May, 1998-2000, was 735 cranes, 34% higher than that reported for May 1970-1971. We estimated 228 (SE = 30) nests in the basin core (excluding renests), 14% higher than a 1971 estimate. Apparent nest success in our study (x?? = 60%, n = 519 nests) was lower than reported for Grays Lake 30-50 years earlier. Daily survival rates (DSRs) of all nests averaged 0.9707 (41.2%). The best model explaining nest survival included year and water depth and their interaction. Nest survival was highest (DSR = 0.9827) in 1998 compared with other years (0.9698-0.9707). Nest survival changed little relative to water depth in 1998, when flooding was extensive and alternative prey (microtines) irrupted, but declined markedly with lower water levels in 2000, the driest year studied. Hypotheses relating nest survival to vegetation height, land use (idle, summer grazing, fall grazing), and date were not supported. In a before-after-control-impact design using 12 experimental fields, nest survival differed among years but not among management treatments (idle, fall graze, fall burn, and summer-graze-idle rotation), nor was there an interaction between year and treatments. However, DSRs in fall-burn fields declined from 0.9781 in 1997-1998 to 0.9503 in 1999-2000 (posttreatment). Changes in the predator community have likely contributed to declines in nest success since the 1950s and 1970s. Our results did not support earlier concerns about effects of habitat management practices on crane productivity. Nest survival could best be enhanced by managing spring water levels. Managers should continue censuses during late April to evaluate long-term relationships to habitat conditions and management.

Nest marking behavior and chemical composition of olfactory cues involved in nest recognition in Megachile rotundata.

Science.gov (United States)

Guédot, Christelle; Buckner, James S; Hagen, Marcia M; Bosch, Jordi; Kemp, William P; Pitts-Singer, Theresa L

2013-08-01

In-nest observations of the solitary bee, Megachile rotundata (F.), revealed that nesting females apply olfactory cues to nests for nest recognition. On their way in and out of the nest, females drag the abdomen along the entire length of the nest, and sometimes deposit fluid droplets from the tip of the abdomen. The removal of bee-marked sections of the nest resulted in hesitation and searching behavior by females, indicating the loss of olfactory cues used for nest recognition. Chemical analysis of female cuticles and the deposits inside marked nesting tubes revealed the presence of hydrocarbons, wax esters, fatty aldehydes, and fatty alcohol acetate esters. Chemical compositions were similar across tube samples, but proportionally different from cuticular extracts. These findings reveal the importance of lipids as chemical signals for nest recognition and suggest that the nest-marking cues are derived from a source in addition to, or other than, the female cuticle.

Effect of Tithonia diversifolia mulch on Atta cephalotes (Hymenoptera: Formicidae) nests.

Science.gov (United States)

Rodríguez, Jonathan; Montoya-Lerma, James; Calle, Zoraida

2015-01-01

Recent studies have shown an insecticidal effect of Tithonia diversifolia (Hemsl.) Gray (Asterales: Asteraceae) foliage on workers of Atta cephalotes L. and inhibitory effects of this plant on the growth of the symbiotic fungus Leucoagaricus gongylophorus (A. Müler) Singer. To evaluate the potential of T. diversifolia as a biological control treatment of this important pest, we assessed the effect of green manure (mulch) of this plant on natural nests of A. cephalotes, in Cali, Colombia. Three treatments were randomly assigned to 30 nests: 1) green mulch of T. diversifolia, 2) green mulch of Miconia sp., Ruiz & Pav. and 3) unmulched control. Every 2 wk for 6 mo, the surface of the nests was completely covered with leaves. Physical and chemical parameters of nest soil were assessed before the first and after the last application of the mulch. Ant foraging in T. diversifolia-treated nests decreased by 60% after the initial applications of the mulch, while nest surface area decreased by 40%. When the nests covered with T. diversifolia were opened, it was observed that the superficial fungus chambers had been relocated at a greater depth. In addition, microbial activity and soil pH increased by 84% and 12%, respectively, in nests covered with plant residues. In conclusion, the continued use of T. diversifolia mulch reduces foraging activity and negatively affects the internal conditions of the colonies, thereby inducing the ants to relocate the fungus chambers within the nests. © The Author 2015. Published by Oxford University Press on behalf of the Entomological Society of America.

Factors Affecting Tocopherol Concentrations in Soybean Seeds.

Science.gov (United States)

Carrera, Constanza S; Seguin, Philippe

2016-12-21

Soybean seeds contain several health-beneficial compounds, including tocopherols, which are used by the nutraceutical and functional food industries. Soybean tocopherol concentrations are, however, highly variable. Large differences observed in tocopherol concentrations among soybean genotypes together with the relatively simple biosynthetic pathway involving few genes support the feasibility of selecting for high-tocopherol soybean. Tocopherol concentrations are also highly influenced by environmental factors and field management. Temperature during seed filling and soil moisture appear to be the main factors affecting tocopherol concentrations; other factors such as soil fertility and solar radiation also affect concentrations and composition. Field management decisions including seeding date, row spacing, irrigation, and fertilization also affect tocopherols. Knowledge of factors affecting soybean tocopherols is essential to develop management strategies that will lead to the production of seeds with consistent target concentrations that will meet the needs of the nutraceutical and functional food industries.

Factors Affecting Wound Healing

OpenAIRE

Guo, S.; DiPietro, L.A.

2010-01-01

Wound healing, as a normal biological process in the human body, is achieved through four precisely and highly programmed phases: hemostasis, inflammation, proliferation, and remodeling. For a wound to heal successfully, all four phases must occur in the proper sequence and time frame. Many factors can interfere with one or more phases of this process, thus causing improper or impaired wound healing. This article reviews the recent literature on the most significant factors that affect cutane...

Web-based Factors Affecting Online Purchasing Behaviour

Science.gov (United States)

Ariff, Mohd Shoki Md; Sze Yan, Ng; Zakuan, Norhayati; Zaidi Bahari, Ahamad; Jusoh, Ahmad

2013-06-01

The growing use of internet and online purchasing among young consumers in Malaysia provides a huge prospect in e-commerce market, specifically for B2C segment. In this market, if E-marketers know the web-based factors affecting online buyers' behaviour, and the effect of these factors on behaviour of online consumers, then they can develop their marketing strategies to convert potential customers into active one, while retaining existing online customers. Review of previous studies related to the online purchasing behaviour in B2C market has point out that the conceptualization and empirical validation of the online purchasing behaviour of Information and Communication Technology (ICT) literate users, or ICT professional, in Malaysia has not been clearly addressed. This paper focuses on (i) web-based factors which online buyers (ICT professional) keep in mind while shopping online; and (ii) the effect of web-based factors on online purchasing behaviour. Based on the extensive literature review, a conceptual framework of 24 items of five factors was constructed to determine web-based factors affecting online purchasing behaviour of ICT professional. Analysis of data was performed based on the 310 questionnaires, which were collected using a stratified random sampling method, from ICT undergraduate students in a public university in Malaysia. The Exploratory factor analysis performed showed that five factors affecting online purchase behaviour are Information Quality, Fulfilment/Reliability/Customer Service, Website Design, Quick and Details, and Privacy/Security. The result of Multiple Regression Analysis indicated that Information Quality, Quick and Details, and Privacy/Security affect positively online purchase behaviour. The results provide a usable model for measuring web-based factors affecting buyers' online purchase behaviour in B2C market, as well as for online shopping companies to focus on the factors that will increase customers' online purchase.

Web-based Factors Affecting Online Purchasing Behaviour

International Nuclear Information System (INIS)

Ariff, Mohd Shoki Md; Yan, Ng Sze; Zakuan, Norhayati; Bahari, Ahamad Zaidi; Jusoh, Ahmad

2013-01-01

The growing use of internet and online purchasing among young consumers in Malaysia provides a huge prospect in e-commerce market, specifically for B2C segment. In this market, if E-marketers know the web-based factors affecting online buyers' behaviour, and the effect of these factors on behaviour of online consumers, then they can develop their marketing strategies to convert potential customers into active one, while retaining existing online customers. Review of previous studies related to the online purchasing behaviour in B2C market has point out that the conceptualization and empirical validation of the online purchasing behaviour of Information and Communication Technology (ICT) literate users, or ICT professional, in Malaysia has not been clearly addressed. This paper focuses on (i) web-based factors which online buyers (ICT professional) keep in mind while shopping online; and (ii) the effect of web-based factors on online purchasing behaviour. Based on the extensive literature review, a conceptual framework of 24 items of five factors was constructed to determine web-based factors affecting online purchasing behaviour of ICT professional. Analysis of data was performed based on the 310 questionnaires, which were collected using a stratified random sampling method, from ICT undergraduate students in a public university in Malaysia. The Exploratory factor analysis performed showed that five factors affecting online purchase behaviour are Information Quality, Fulfilment/Reliability/Customer Service, Website Design, Quick and Details, and Privacy/Security. The result of Multiple Regression Analysis indicated that Information Quality, Quick and Details, and Privacy/Security affect positively online purchase behaviour. The results provide a usable model for measuring web-based factors affecting buyers' online purchase behaviour in B2C market, as well as for online shopping companies to focus on the factors that will increase customers' online purchase.

Determining the Factors Affecting Labor Productivity of Nurses

Directory of Open Access Journals (Sweden)

Yurdanur Dikmen

2016-12-01

Results: It was found that the 45.5% of nurses participated in the study were in the 23-53 age group, 79.5% were women, 76.9% married, 41.1% associate degree graduates. 42.3% of nurses' durations of professional experience were 0-5 years, 22.4% of nurses were clinical chief, 69.2% were working as shifts. Participants believe that the factors affecting the labor productivity were respectively organizational factors, ergonomic factors and personal factors. When organizational factors was examined; nurses stated that the lack of working personnel in the section, the low wages and unequal wages for the same work, the long working hours and the system which based on personal relations instead of merit were affecting productivity. The factors affecting labor productivity of nurses were not different according to age, gender, education level and marital status (p>0.05, but different according to mode of operation and years of experience (p<0.05. Conclusion: According to this study, it was found that there are many factors that affect the efficiency of the nurses. The most important factors affecting nurses' efficiency were determined as wage and working conditions. [J Contemp Med 2016; 6(4.000: 334-342

CO2 efflux from subterranean nests of ant communities in a seasonal tropical forest, Thailand

OpenAIRE

Hasin, Sasitorn; Ohashi, Mizue; Yamada, Akinori; Hashimoto, Yoshiaki; Tasen, Wattanachai; Kume, Tomonori; Yamane, Seiki

2014-01-01

Many ant species construct subterranean nests. The presence of their nests may explain soil respiration “hot spots”, an important factor in the high CO2 efflux from tropical forests. However, no studies have directly measured CO2 efflux from ant nests. We established 61 experimental plots containing 13 subterranean ant species to evaluate the CO2 efflux from subterranean ant nests in a tropical seasonal forest, Thailand. We examined differences in nest CO2 efflux among ant species. We determi...

Determining nest predators of the Least Bell's Vireo through point counts, tracking stations, and video photography

Science.gov (United States)

Peterson, Bonnie L.; Kus, Barbara E.; Deutschman, Douglas H.

2004-01-01

We compared three methods to determine nest predators of the Least Bell's Vireo (Vireo bellii pusillus) in San Diego County, California, during spring and summer 2000. Point counts and tracking stations were used to identify potential predators and video photography to document actual nest predators. Parental behavior at depredated nests was compared to that at successful nests to determine whether activity (frequency of trips to and from the nest) and singing vs. non-singing on the nest affected nest predation. Yellow-breasted Chats (Icteria virens) were the most abundant potential avian predator, followed by Western Scrub-Jays (Aphelocoma californica). Coyotes (Canis latrans) were abundant, with smaller mammalian predators occurring in low abundance. Cameras documented a 48% predation rate with scrub-jays as the major nest predators (67%), but Virginia opossums (Didelphis virginiana, 17%), gopher snakes (Pituophis melanoleucus, 8%) and Argentine ants (Linepithema humile, 8%) were also confirmed predators. Identification of potential predators from tracking stations and point counts demonstrated only moderate correspondence with actual nest predators. Parental behavior at the nest prior to depredation was not related to nest outcome.

Sharp-Tailed Grouse Nest Survival and Nest Predator Habitat Use in North Dakota's Bakken Oil Field.

Directory of Open Access Journals (Sweden)

Paul C Burr

Full Text Available Recent advancements in extraction technologies have resulted in rapid increases of gas and oil development across the United States and specifically in western North Dakota. This expansion of energy development has unknown influences on local wildlife populations and the ecological interactions within and among species. Our objectives for this study were to evaluate nest success and nest predator dynamics of sharp-tailed grouse (Tympanuchus phasianellus in two study sites that represented areas of high and low energy development intensities in North Dakota. During the summers of 2012 and 2013, we monitored 163 grouse nests using radio telemetry. Of these, 90 nests also were monitored using miniature cameras to accurately determine nest fates and identify nest predators. We simultaneously conducted predator surveys using camera scent stations and occupancy modeling to estimate nest predator occurrence at each site. American badgers (Taxidea taxus and striped skunks (Mephitis mephitis were the primary nest predators, accounting for 56.7% of all video recorded nest depredations. Nests in our high intensity gas and oil area were 1.95 times more likely to succeed compared to our minimal intensity area. Camera monitored nests were 2.03 times more likely to succeed than non-camera monitored nests. Occupancy of mammalian nest predators was 6.9 times more likely in our study area of minimal gas and oil intensity compared to the high intensity area. Although only a correlative study, our results suggest energy development may alter the predator community, thereby increasing nest success for sharp-tailed grouse in areas of intense development, while adjacent areas may have increased predator occurrence and reduced nest success. Our study illustrates the potential influences of energy development on the nest predator-prey dynamics of sharp-tailed grouse in western North Dakota and the complexity of evaluating such impacts on wildlife.

Hawaii ESI: NESTS (Nest Points)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for seabird nesting colonies in coastal Hawaii. Vector points in this data set represent locations of...

Maryland ESI: NESTS (Nest Points)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for raptors in Maryland. Vector points in this data set represent bird nesting sites. Species-specific...

Selection of arboreal termitaria for nesting by cooperatively breeding Micronesian Kingfishers Todiramphus cinnamominus reichenbachii

Science.gov (United States)

Kesler, Dylan C.; Haig, Susan M.

2005-01-01

Limited nest-site availability appears to be an important factor in the evolution of delayed dispersal and cooperative breeding in some cavity-nesting species. The cooperatively breeding Pohnpei subspecies of Micronesian Kingfisher Todiramphus cinnamominus reichenbachii excavates nest cavities from the nests of arboreal termites Nasutitermes spp., or termitaria. In this first published description of nest-sites for this subspecies, we used surveys, remote sensing and radiotelemetry to evaluate the relationship between nest-site availability and co-operation. Results illustrate that nest termitaria are higher in the forest canopy, larger in volume and occur in areas with more contiguous canopy cover than unused termitaria. Nest termitaria were selected independently of the proximity to forest edges and territory boundaries, and we found no difference in characteristics of termitaria used by cooperative groups and breeding pairs. Logistic regression modelling indicated that termitaria with nest-like characteristics were not limited in abundance, suggesting that neither the prospects of inheriting nesting resources nor limited nest-site abundance are probable explanations for delayed dispersal in the Pohnpei subspecies of Micronesian Kingfisher.

Generalist predator, cyclic voles and cavity nests: testing the alternative prey hypothesis.

Science.gov (United States)

Pöysä, Hannu; Jalava, Kaisa; Paasivaara, Antti

2016-12-01

The alternative prey hypothesis (APH) states that when the density of the main prey declines, generalist predators switch to alternative prey and vice versa, meaning that predation pressure on the alternative prey should be negatively correlated with the density of the main prey. We tested the APH in a system comprising one generalist predator (pine marten, Martes martes), cyclic main prey (microtine voles, Microtus agrestis and Myodes glareolus) and alternative prey (cavity nests of common goldeneye, Bucephala clangula); pine marten is an important predator of both voles and common goldeneye nests. Specifically, we studied whether annual predation rate of real common goldeneye nests and experimental nests is negatively associated with fluctuation in the density of voles in four study areas in southern Finland in 2000-2011. Both vole density and nest predation rate varied considerably between years in all study areas. However, we did not find support for the hypothesis that vole dynamics indirectly affects predation rate of cavity nests in the way predicted by the APH. On the contrary, the probability of predation increased with vole spring abundance for both real and experimental nests. Furthermore, a crash in vole abundance from previous autumn to spring did not increase the probability of predation of real nests, although it increased that of experimental nests. We suggest that learned predation by pine marten individuals, coupled with efficient search image for cavities, overrides possible indirect positive effects of high vole density on the alternative prey in our study system.

Biomechanical testing of materials in avian nests provides insight into nest construction behaviour

OpenAIRE

Biddle, Lucia E.; Deeming, D. Charles; Goodman, Adrian M.

2015-01-01

Animals that use materials to build nest structures have long since fascinated biologists and engineers alike. Avian nests are generally composed of collected materials brought together into a cup-like structure in which the bird sits to incubate eggs and, in many cases, it is where chicks are reared. Hence, the materials in a nest can be presumed to be loaded in compression, but relatively few studies have investigated the mechanical role of the nest elements and their position w...

Nesting biology of Trypoxylon (Trypargilum) lactitarse Saussure (Hymenoptera, Crabronidae) in trap-nests in Southern Brazil

OpenAIRE

Buschini,M. L. T.; Niesing,F.; Wolff,L. L.

2006-01-01

This study was carried in the Parque Municipal das Araucárias in the municipality of Guarapuava, state of Paraná, Southern Brazil. Three hundred and sixty five nests of T. lactitarse were obtained using trap-nests of 0.7, 1.0, and 1.3 cm in diameter. All of them had similar architecture, regardless of the diameter of the trap-nest. Completed nests consisted of a linear series of brood cells whose average number per nest was of 3.3, 4.0 and 3.6 for the nests with 0.7 cm, 1.0 cm and 1.3 cm in d...

Factors affecting endoglucanase production by Trichoderma reesei ...

African Journals Online (AJOL)

Jane

2011-08-22

Aug 22, 2011 ... from the ANOVA analysis have a significant value of Pmodel>F= 0.0008 and R2 .... there are various environmental and nutritional factors ... reported to affect cellulase production from wheat straw ... many factors affecting simultaneously the fermentation ..... and control its stability (Kalra and Sandhu, 1986).

Louisiana ESI: NESTS (Nest Points)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for seabird and wading bird nesting colonies in coastal Louisiana. Vector points in this data set represent...

Raptor nest management on power lines

Energy Technology Data Exchange (ETDEWEB)

Harness, R.E. [EDM International Inc., Fort Collins, CO (United States)

2005-07-01

Many utilities in South Africa are now implementing labor-intensive methods to combat raptor nesting on power transmission lines. Methods have typically included direct nest removal and trimming of nest materials. However, the process is often unsuccessful, and utilities are now learning to accommodate the raptor nests. This paper argued that managing nests on utility structures has solved many operational problems and has resulted in positive publicity for many line operators. Nest management options included the use of stick deflectors to prevent nest material from accumulating during initial nest construction, as well as encouraging raptors to shift their efforts to a more suitable location. Raptors will often accept alternative nesting platforms, and taller, surrogate nesting poles can be placed next to distribution line structures. Elevated platforms can also be placed on problematic distribution structures, but may result in birds coming into contact with unprotected equipment. It was concluded that a successful nest management program includes plans to make nearby lines safe for raptors and to prevent their electrocution. Providing nests with bird-friendly utility configurations can result in electric facilities enhancing wild raptor populations without impacting power reliability. 14 refs., 9 figs.

Posture and movement in healthy preterm infants in supine position in and outside the nest

NARCIS (Netherlands)

Ferrari, F.; Bertoncelli, N.; Gallo, C.; Roversi, M. F.; Guerra, M. P.; Ranzi, A.; Madders-Algra, M.

Objective: To evaluate whether lying in a nest affects the posture and spontaneous movements of healthy preterm infants. Method: 10 healthy preterm infants underwent serial video recording in the supine position, when lying in a nest and outside it, at three ages: 30-33 weeks postmenstrual age (PMA)

Nest-site selection and nest success of an Arctic-breeding passerine, Smith's Longspur, in a changing climate

Science.gov (United States)

McFarland, Heather R.; Kendall, Steve J.; Powell, Abby

2017-01-01

Despite changes in shrub cover and weather patterns associated with climate change in the Arctic, little is known about the breeding requirements of most passerines tied to northern regions. We investigated the nesting biology and nest habitat characteristics of Smith's Longspurs (Calcarius pictus) in 2 study areas in the Brooks Range of Alaska, USA. First, we examined variation in nesting phenology in relation to local temperatures. We then characterized nesting habitat and analyzed nest-site selection for a subset of nests (n = 86) in comparison with paired random points. Finally, we estimated the daily survival rate of 257 nests found in 2007–2013 with respect to both habitat characteristics and weather variables. Nest initiation was delayed in years with snow events, heavy rain, and freezing temperatures early in the breeding season. Nests were typically found in open, low-shrub tundra, and never among tall shrubs (mean shrub height at nests = 26.8 ± 6.7 cm). We observed weak nest-site selection patterns. Considering the similarity between nest sites and paired random points, coupled with the unique social mating system of Smith's Longspurs, we suggest that habitat selection may occur at the neighborhood scale and not at the nest-site scale. The best approximating model explaining nest survival suggested a positive relationship with the numbers of days above 21°C that an individual nest experienced; there was little support for models containing habitat variables. The daily nest survival rate was high (0.972–0.982) compared with that of most passerines in forested or grassland habitats, but similar to that of passerines nesting on tundra. Considering their high nesting success and ability to delay nest initiation during inclement weather, Smith's Longspurs may be resilient to predicted changes in weather regimes on the breeding grounds. Thus, the greatest threat to breeding Smith's Longspurs associated with climate change may be the loss of low

Contextual investigation of factors affecting sludge accumulation ...

African Journals Online (AJOL)

Pit latrines in slums areas of Uganda fill up faster than might be expected from some estimates owing to inappropriate use and failure to consider critical factors affecting sludge accumulation rates at the planning, design and construction stages. This study sought to investigate factors affecting filling rates of lined pit latrines ...

Nesting ecology of roseate spoonbills at Nueces Bay, Texas

Science.gov (United States)

White, Donald H.; Mitchell, Christine A.; Cromartie, E.

1982-01-01

We conducted a study in 1978-1980 of the nesting ecology of Roseate Spoonbills (Ajaia ajaja) in a relatively polluted environment at Nueces Bay, Texas. For 154 marked nests, the average clutch size was 3.0 eggs; 73% of the eggs hatched, and 87% of the nests were successful (hatched at least 1 young). The average nest success rate (total fledglings:total eggs) was 50% or 1.5 fledglings per total nests. Incubation began the day after the first egg was laid, and the incubation period for each egg was 22 days. Eggs hatched in the order that they were laid; the first and second eggs hatched on consecutive days, and the second, third, and fourth eggs hatched every other day. Nest composition and size were highly consistent, but nest placement varied considerably and was dependent on the vegetative configuration of the dredge-material islands. Growth rate of nestlings conformed to a 'standard' growth curve, where body weight of nestlings at fledging equaled that of adults. There was no difference in weight gain among siblings based on actual age. Nestlings fledged at about 6 weeks of age, when feather development was complete. At fledging, the bills of juveniles had almost reached adult width, but bill length was only 67% that of adults. In general, environmental pollutants were low (<2 ppm) in spoonbill eggs, though a few eggs contained elevated concentrations of DDE (up to 15 ppm, wet weight). Some eggshells were 5% thinner than those in museum collections, but the degree of thinning was not within the range known to cause population declines. We conclude that organochlorine pollutants are not adversely affecting spoonbill reproduction at Nueces Bay, Texas, though the area is surrounded by industries and agricultural lands. Apparently, spoonbills are less sensitive to these contaminants than are other aquatic species.

Factors Affecting Wound Healing

Science.gov (United States)

Guo, S.; DiPietro, L.A.

2010-01-01

Wound healing, as a normal biological process in the human body, is achieved through four precisely and highly programmed phases: hemostasis, inflammation, proliferation, and remodeling. For a wound to heal successfully, all four phases must occur in the proper sequence and time frame. Many factors can interfere with one or more phases of this process, thus causing improper or impaired wound healing. This article reviews the recent literature on the most significant factors that affect cutaneous wound healing and the potential cellular and/or molecular mechanisms involved. The factors discussed include oxygenation, infection, age and sex hormones, stress, diabetes, obesity, medications, alcoholism, smoking, and nutrition. A better understanding of the influence of these factors on repair may lead to therapeutics that improve wound healing and resolve impaired wounds. PMID:20139336

Do ducks and songbirds initiate more nests when the probability of survival is greater?

Science.gov (United States)

Grant, Todd A.; Shaffer, Terry L.

2015-01-01

Nesting chronology in grassland birds can vary by species, locality, and year. The date a nest is initiated can influence the subsequent probability of its survival in some grassland bird species. Because predation is the most significant cause of nest loss in grassland birds, we examined the relation between timing of nesting and nest survival. Periods of high nest survival that correspond with the peak of nesting activity might reflect long-term adaptations to specific predation pressures commonly recurring during certain periods of the nesting cycle. We evaluated this theory by comparing timing of nesting with date-specific nest survival rates for several duck and passerine species breeding in north-central North Dakota during 1998–2003. Nest survival decreased seasonally with date for five of the seven species we studied. We found little evidence to support consistent relations between timing of nesting, the number of nest initiations, and nest survival for any species we studied, suggesting that factors other than nest predation may better explain nesting chronology for these species. The apparent mismatch between date-specific patterns of nest survival and nest initiation underscores uncertainty about the process of avian nest site selection driven mainly by predation. Although timing of nesting differed among species, the general nesting period was fairly predictable across all years of study, suggesting the potential for research activities or management actions to be timed to take advantage of known periods when nests are active (or inactive). However, our results do not support the notion that biologists can take advantage of periods when many nests are active and survival is also high.

Habitat fragmentation reduces nest survival in an Afrotropical bird community in a biodiversity hotspot.

Science.gov (United States)

Newmark, William D; Stanley, Thomas R

2011-07-12

Ecologists have long hypothesized that fragmentation of tropical landscapes reduces avian nest success. However, this hypothesis has not been rigorously assessed because of the difficulty of finding large numbers of well-hidden nests in tropical forests. Here we report that in the East Usambara Mountains in Tanzania, which are part of the Eastern Arc Mountains, a global biodiversity hotspot, that daily nest survival rate and nest success for seven of eight common understory bird species that we examined over a single breeding season were significantly lower in fragmented than in continuous forest, with the odds of nest failure for these seven species ranging from 1.9 to 196.8 times higher in fragmented than continuous forest. Cup-shaped nests were particularly vulnerable in fragments. We then examined over six breeding seasons and 14 study sites in a multivariable survival analysis the influence of landscape structure and nest location on daily nest survival for 13 common species representing 1,272 nests and four nest types (plate, cup, dome, and pouch). Across species and nest types, area, distance of nest to edge, and nest height had a dominant influence on daily nest survival, with area being positively related to nest survival and distance of nest to edge and nest height being both positively and negatively associated with daily nest survival. Our results indicate that multiple environmental factors contribute to reduce nest survival within a tropical understory bird community in a fragmented landscape and that maintaining large continuous forest is important for enhancing nest survival for Afrotropical understory birds.

Unusual raptor nests around the world

Science.gov (United States)

Ellis, D.H.; Craig, T.; Craig, E.; Postupalsky, S.; LaRue, C.T.; Nelson, R.W.; Anderson, D.W.; Henny, C.J.; Watson, J.; Millsap, B.A.; Dawson, J.W.; Cole, K.L.; Martin, E.M.; Margalida, A.; Kung, P.

2009-01-01

From surveys in many countries, we report raptors using unusual nesting materials (e.g., paper money, rags, metal, antlers, and large bones) and unusual nesting situations. For example, we documented nests of Steppe Eagles Aquila nipalensis and Upland Buzzards Buteo hemilasius on the ground beside well-traveled roads, Saker Falcon Falco cherrug eyries in attics and a cistern, and Osprey Pandion haliaetus nests on the masts of boats and on a suspended automobile. Other records include a Golden Eagle A. chrysaetos nest 7.0 m in height, believed to be the tallest nest ever described, and, for the same species, we report nesting in rudimentary nests. Some nest sites are within a few meters of known predators or competitors. These unusual observations may be important in revealing the plasticity of a species' behavioral repertoire. ?? 2009 The Raptor Research Foundation, Inc.

Edge, height and visibility effects on nest predation by birds and mammals in the Brazilian cerrado

Science.gov (United States)

Dodonov, Pavel; Paneczko, Ingrid Toledo; Telles, Marina

2017-08-01

Edge influence is one of the main impacts in fragmented landscapes; yet, most of studies on edge influence have focused on high-contrast edges, and the impacts of low-contrast edges and narrow linear openings are less understood. Edge influence often affects bird nest predation, but these effects are not ubiquitous and may depend on characteristics such as nest height and visibility. We performed an experiment on nest predation in a migratory passerine, Elaenia chiriquensis (Lesser Elaenia; Passeriformes: Tyrannidae), in a savanna vegetation of the Brazilian Cerrado biome in South-Eastern Brazil. We used 89 real E. chiriquensis nests, collected during previous reproductive seasons, with two plasticine eggs in each, and randomly distributed them at two locations (edge - up to 20 m from a firebreak edge and interior - approx. 150-350 m from the edge) and two heights (low - 60-175 cm and high - 190-315 cm above ground). We also measured leaf and branch density around each nest. We performed this study on two 15-days campaigns, checking the nests every 2-3 days and removing those with predation marks. We sorted the predation marks into those made by birds, mammals, or unidentified predators, and used generalized linear models to assess the effects of location, height and leaf density on survival time and predator type. Only four nests had not been predated during the experiment; 55 nests were predated by birds, 7 by mammals, and 23 by unidentified predators. Low nests in the interior tended to have larger survival times whereas high nests at the edge tended to be more predated by birds and less predated by mammals. Thus, even a low-contrast (firebreak) edge may significantly increase nest predation, which is also affected by the nest's height, mainly due to predation by birds. These effects may be due to predator movement along the edge as well as to edge-related changes in vegetation structure. We suggest that higher-contrast edges which may also be used as movement

How do Neoseiulus californicus (Acari: Phytoseiidae) females penetrate densely webbed spider mite nests?

Science.gov (United States)

Montserrat, M; de la Peña, F; Hormaza, J I; González-Fernández, J J

2008-02-01

The persea mite Oligonychus perseae is a pest of avocado trees that builds extremely dense webbed nests that protect them against natural enemies, including phytoseiid mites. Nests have one or two marginal entrances that are small and flattened. The predatory mite Neoseiulus californicus co-occurs with O. perseae in the avocado orchards of the south-east of Spain. Penetration inside nests through the entrances by this predator is thought to be hindered by its size and its globular-shaped body. However, in the field it has repeatedly been found inside nests that were clearly ripped. Perhaps penetration of the nests has been facilitated by nest wall ripping caused by some other species or by unfavourable abiotic factors. However, to assess whether N. californicus is also able to enter the nest of O. perseae by itself, we carried out laboratory experiments and made a short film. They show how this predator manages to overcome the webbed wall, and that it can penetrate and forage inside nests of O. perseae.

Sexually selected nest-building--Pomatoschistus minutus males build smaller nest-openings in the presence of sneaker males.

Science.gov (United States)

Svensson, O; Kvarnemo, C

2003-09-01

Both natural selection and sexual selection may act on nest-building. We tested experimentally how different regimes of egg-predation and male-male competition influence nest-building before mating, using the marine fish sand goby, Pomatoschistus minutus. Males with sneaker males present built the smallest nest-openings, smaller than males held alone or with Pomatoschistus microps males (which may predate eggs and compete over nest-sites but not compete over fertilizations). Males with visual access to other nest-building males tended also to build smaller openings than males held alone or with P. microps. Males with egg-predators present built nests with openings not differing significantly from any other treatment. Our results indicate that the small nest-openings found in the sneaker male treatment are sexually selected through protection against sneaking or by female choice. Across treatments, time span before a male started to build his nest also explained variation in nest-opening width; males starting late built larger nest-openings.

Development with age of nest box use and gregarious nesting in laying hens

DEFF Research Database (Denmark)

Riber, Anja Brinch

2010-01-01

in position (left + corner, middle, and right). Nesting behaviour was video recorded for 5 days in each of five distinct periods: age 20, 26, 32, 38, and 44 weeks. The total number of visits and the number of gregarious visits were higher in the left nest box than in the other two nest boxes at all ages...

A miniaturised, nested-cylindrical electrostatic analyser geometry for dual electron and ion, multi-energy measurements

Energy Technology Data Exchange (ETDEWEB)

Bedington, Robert, E-mail: r.bedington@nus.edu.sg; Kataria, Dhiren; Smith, Alan

2015-09-01

The CATS (Cylindrical And Tiny Spectrometer) electrostatic optics geometry features multiple nested cylindrical analysers to simultaneously measure multiple energies of electron and multiple energies of ion in a configuration that is targeted at miniaturisation and MEMS fabrication. In the prototyped model, two configurations of cylindrical analyser were used, featuring terminating side-plates that caused particle trajectories to either converge (C type) or diverge (D type) in the axial direction. Simulations show how these different electrode configurations affect the particle focussing and instrument parameters; C-type providing greater throughputs but D-type providing higher resolving powers. The simulations were additionally used to investigate unexpected plate spacing variations in the as-built model, revealing that the k-factors are most sensitive to the width of the inter-electrode spacing at its narrowest point. - Highlights: • A new nested cylindrical miniaturised electrostatic analyser geometry is described. • “Converging” (C) and “diverging” (D) type channel properties are investigated. • C channels are shown to have greater throughputs and D greater resolving powers. • Plate factors are shown to be sensitive to the minimum in inter-electrode spacing.

Presence of Breeding Birds Improves Body Condition for a Crocodilian Nest Protector.

Science.gov (United States)

Nell, Lucas A; Frederick, Peter C; Mazzotti, Frank J; Vliet, Kent A; Brandt, Laura A

2016-01-01

Ecological associations where one species enhances habitat for another nearby species (facilitations) shape fundamental community dynamics and can promote niche expansion, thereby influencing how and where species persist and coexist. For the many breeding birds facing high nest-predation pressure, enemy-free space can be gained by nesting near more formidable animals for physical protection. While the benefits to protected species seem well documented, very few studies have explored whether and how protector species are affected by nest protection associations. Long-legged wading birds (Pelecaniformes and Ciconiiformes) actively choose nesting sites above resident American alligators (Alligator mississippiensis), apparently to take advantage of the protection from mammalian nest predators that alligator presence offers. Previous research has shown that wading bird nesting colonies could provide substantial food for alligators in the form of dropped chicks. We compared alligator body condition in similar habitat with and without wading bird nesting colonies present. Alligator morphometric body condition indices were significantly higher in colony than in non-colony locations, an effect that was statistically independent of a range of environmental variables. Since colonially nesting birds and crocodilians co-occur in many tropical and subtropical wetlands, our results highlight a potentially widespread keystone process between two ecologically important species-groups. These findings suggest the interaction is highly beneficial for both groups of actors, and illustrate how selective pressures may have acted to form and reinforce a strongly positive ecological interaction.

Presence of Breeding Birds Improves Body Condition for a Crocodilian Nest Protector

Science.gov (United States)

Nell, Lucas A.; Frederick, Peter C.; Mazzotti, Frank J.; Vliet, Kent A.; Brandt, Laura A.

2016-01-01

Ecological associations where one species enhances habitat for another nearby species (facilitations) shape fundamental community dynamics and can promote niche expansion, thereby influencing how and where species persist and coexist. For the many breeding birds facing high nest-predation pressure, enemy-free space can be gained by nesting near more formidable animals for physical protection. While the benefits to protected species seem well documented, very few studies have explored whether and how protector species are affected by nest protection associations. Long-legged wading birds (Pelecaniformes and Ciconiiformes) actively choose nesting sites above resident American alligators (Alligator mississippiensis), apparently to take advantage of the protection from mammalian nest predators that alligator presence offers. Previous research has shown that wading bird nesting colonies could provide substantial food for alligators in the form of dropped chicks. We compared alligator body condition in similar habitat with and without wading bird nesting colonies present. Alligator morphometric body condition indices were significantly higher in colony than in non-colony locations, an effect that was statistically independent of a range of environmental variables. Since colonially nesting birds and crocodilians co-occur in many tropical and subtropical wetlands, our results highlight a potentially widespread keystone process between two ecologically important species-groups. These findings suggest the interaction is highly beneficial for both groups of actors, and illustrate how selective pressures may have acted to form and reinforce a strongly positive ecological interaction. PMID:26934602

Breeding phenology of birds: mechanisms underlying seasonal declines in the risk of nest predation.

Directory of Open Access Journals (Sweden)

Kathi L Borgmann

Full Text Available Seasonal declines in avian clutch size are well documented, but seasonal variation in other reproductive parameters has received less attention. For example, the probability of complete brood mortality typically explains much of the variation in reproductive success and often varies seasonally, but we know little about the underlying cause of that variation. This oversight is surprising given that nest predation influences many other life-history traits and varies throughout the breeding season in many songbirds. To determine the underlying causes of observed seasonal decreases in risk of nest predation, we modeled nest predation of Dusky Flycatchers (Empidonax oberholseri in northern California as a function of foliage phenology, energetic demand, developmental stage, conspecific nest density, food availability for nest predators, and nest predator abundance. Seasonal variation in the risk of nest predation was not associated with seasonal changes in energetic demand, conspecific nest density, or predator abundance. Instead, seasonal variation in the risk of nest predation was associated with foliage density (early, but not late, in the breeding season and seasonal changes in food available to nest predators. Supplemental food provided to nest predators resulted in a numerical response by nest predators, increasing the risk of nest predation at nests that were near supplemental feeders. Our results suggest that seasonal changes in foliage density and factors associated with changes in food availability for nest predators are important drivers of temporal patterns in risk of avian nest predation.

Breeding phenology of birds: mechanisms underlying seasonal declines in the risk of nest predation.

Science.gov (United States)

Borgmann, Kathi L; Conway, Courtney J; Morrison, Michael L

2013-01-01

Seasonal declines in avian clutch size are well documented, but seasonal variation in other reproductive parameters has received less attention. For example, the probability of complete brood mortality typically explains much of the variation in reproductive success and often varies seasonally, but we know little about the underlying cause of that variation. This oversight is surprising given that nest predation influences many other life-history traits and varies throughout the breeding season in many songbirds. To determine the underlying causes of observed seasonal decreases in risk of nest predation, we modeled nest predation of Dusky Flycatchers (Empidonax oberholseri) in northern California as a function of foliage phenology, energetic demand, developmental stage, conspecific nest density, food availability for nest predators, and nest predator abundance. Seasonal variation in the risk of nest predation was not associated with seasonal changes in energetic demand, conspecific nest density, or predator abundance. Instead, seasonal variation in the risk of nest predation was associated with foliage density (early, but not late, in the breeding season) and seasonal changes in food available to nest predators. Supplemental food provided to nest predators resulted in a numerical response by nest predators, increasing the risk of nest predation at nests that were near supplemental feeders. Our results suggest that seasonal changes in foliage density and factors associated with changes in food availability for nest predators are important drivers of temporal patterns in risk of avian nest predation.

Locating chimpanzee nests and identifying fruiting trees with an unmanned aerial vehicle.

Science.gov (United States)

van Andel, Alexander C; Wich, Serge A; Boesch, Christophe; Koh, Lian Pin; Robbins, Martha M; Kelly, Joseph; Kuehl, Hjalmar S

2015-10-01

Monitoring of animal populations is essential for conservation management. Various techniques are available to assess spatiotemporal patterns of species distribution and abundance. Nest surveys are often used for monitoring great apes. Quickly developing technologies, including unmanned aerial vehicles (UAVs) can be used to complement these ground-based surveys, especially for covering large areas rapidly. Aerial surveys have been used successfully to detect the nests of orang-utans. It is unknown if such an approach is practical for African apes, which usually build their nests at lower heights, where they might be obscured by forest canopy. In this 2-month study, UAV-derived aerial imagery was used for two distinct purposes: testing the detectability of chimpanzee nests and identifying fruiting trees used by chimpanzees in Loango National Park (Gabon). Chimpanzee nest data were collected through two approaches: we located nests on the ground and then tried to detect them in UAV photos and vice versa. Ground surveys were conducted using line transects, reconnaissance trails, and opportunistic sampling during which we detected 116 individual nests in 28 nest groups. In complementary UAV images we detected 48% of the individual nests (68% of nest groups) in open coastal forests and 8% of individual nests (33% of nest groups) in closed canopy inland forests. The key factor for nest detectability in UAV imagery was canopy openness. Data on fruiting trees were collected from five line transects. In 122 UAV images 14 species of trees (N = 433) were identified, alongside 37 tree species (N = 205) in complementary ground surveys. Relative abundance of common tree species correlated between ground and UAV surveys. We conclude that UAVs have great potential as a rapid assessment tool for detecting chimpanzee presence in forest with open canopy and assessing fruit tree availability. UAVs may have limited applicability for nest detection in closed canopy forest. �

Social Complexity and Nesting Habits Are Factors in the Evolution of Antimicrobial Defences in Wasps

OpenAIRE

Hoggard, Stephen J.; Wilson, Peter D.; Beattie, Andrew J.; Stow, Adam J.

2011-01-01

Microbial diseases are important selective agents in social insects and one major defense mechanism is the secretion of cuticular antimicrobial compounds. We hypothesized that given differences in group size, social complexity, and nest type the secretions of these antimicrobials will be under different selective pressures. To test this we extracted secretions from nine wasp species of varying social complexity and nesting habits and assayed their antimicrobial compounds against cultures of S...

Identification of factors affecting individual industries

Directory of Open Access Journals (Sweden)

Maryam Sadat Mirzadeh

2017-10-01

Full Text Available High knowledge and technology are rapidly becoming a competitive advantage in today’s world. Individual industries are considered one of the key sectors in the country’s industry. Ranking the factors that affect these industries makes us more familiar with their effectiveness and helps us take actions to improve such factors in knowledge-based companies. Consequently, based on previous research studies on Individual Industries, field observations, and a questionnaire prepared by the researchers, the current study explores and classifies the factors affecting the establishment of these industries. Regarding its purpose, this is an applied research, and regarding data collection, it is a descriptive survey. Using purposive sampling, 60 questionnaires were collected and effective factors were classified applying the SPSS software and the TOPSIS technique. This study suggests that content factors are ranked first place, while contextual and structural factors are ranked second and third, respectively. Therefore, executives and managers in single industries are recommended to strengthen joint enterprise norms and dominant values and beliefs in knowledge-based companies in order to help the growth and development of single industries.

Nest-site selection by cavity-nesting birds in relation to postfire salvage logging

Science.gov (United States)

Victoria A. Saab; Robin E. Russell; Jonathan G. Dudley

2009-01-01

Large wildfire events in coniferous forests of the western United States are often followed by postfire timber harvest. The long-term impacts of postfire timber harvest on fire-associated cavity-nesting bird species are not well documented. We studied nest-site selection by cavity-nesting birds over a 10-year period (1994-2003), representing 1-11 years after fire, on...

Contrasting nest survival patterns for ducks and songbirds in northern mixed-grass prairie

Science.gov (United States)

Grant, Todd; Shaffer, Terry L.; Madden, Elizabeth M.; Nenneman, Melvin P.

2017-01-01

Management actions intended to protect or improve habitat for ducks may benefit grassland-nesting passerines, but scant information is available to explore this assumption. During 1998–2003, we examined nest survival of ducks and songbirds to determine whether effects of prescribed fire and other habitat features (e.g., shrub cover and distance to habitat edges) were similar for ducks and passerines breeding in North Dakota. We used the logistic-exposure method to estimate survival of duck and songbird nests (n = 3,171). We used an information-theoretic approach to identify factors that most influenced nest survival. Patterns of nest survival were markedly different between taxonomic groups. For ducks, nest survival was greater during the first postfire nesting season (daily survival rate [DSR] = 0.957, 85% CI = 0.951–0.963), relative to later postfire nesting seasons (DSR = 0.946, 85% CI = 0.942–0.950). Furthermore duck nest survival and nest densities were inversely related. Duck nest survival also was greater as shrub cover decreased and as distance from cropland and wetland edges increased. Passerines had lower nest survival during the first postfire nesting season (DSR = 0.934, 85% CI = 0.924–0.944), when densities also were low compared to subsequent postfire nesting seasons (DSR = 0.947, 85% CI = 0.944–0.950). Parasitism by brown-headed cowbirds (Molothrus ater) reduced passerine nest survival and this effect was more pronounced during the first postfire nesting season compared to subsequent nesting seasons. Passerine nest survival was greater as shrub cover decreased and perhaps for more concealed nests. Duck and songbird nest survival rates were not correlated during this study and for associated studies that examined additional variables using the same dataset, suggesting that different mechanisms influenced their survival. Based on our results, ducks should not be considered direct surrogates for passerines

Artificial covering on trap nests improves the colonization of trap-nesting wasps

OpenAIRE

Taki, Hisatomo; Kevan, Peter G.; Viana, Blandina Felipe; Silva, Fabiana O.; Buck, Matthias

2008-01-01

Acesso restrito: Texto completo. p. 225-229 To evaluate the role that a trap-nest cover might have on sampling methodologies, the abundance of each species of trap-nesting Hymenoptera and the parasitism rate in a Canadian forest were compared between artificially covered and uncovered traps. Of trap tubes exposed at eight forest sites in six trap-nest boxes, 531 trap tubes were occupied and 1216 individuals of 12 wasp species of four predatory families, Vespidae (Eumeninae), Crabronidae...

Nest Predation Deviates from Nest Predator Abundance in an Ecologically Trapped Bird

OpenAIRE

Hollander, Franck A.; Van Dyck, Hans; San Martin, Gilles; Titeux, Nicolas

2015-01-01

In human-modified environments, ecological traps may result from a preference for low-quality habitat where survival or reproductive success is lower than in high-quality habitat. It has often been shown that low reproductive success for birds in preferred habitat types was due to higher nest predator abundance. However, between-habitat differences in nest predation may only weakly correlate with differences in nest predator abundance. An ecological trap is at work in a farmland bird (Lanius ...

Model of the best-of-N nest-site selection process in honeybees

Science.gov (United States)

Reina, Andreagiovanni; Marshall, James A. R.; Trianni, Vito; Bose, Thomas

2017-05-01

The ability of a honeybee swarm to select the best nest site plays a fundamental role in determining the future colony's fitness. To date, the nest-site selection process has mostly been modeled and theoretically analyzed for the case of binary decisions. However, when the number of alternative nests is larger than two, the decision-process dynamics qualitatively change. In this work, we extend previous analyses of a value-sensitive decision-making mechanism to a decision process among N nests. First, we present the decision-making dynamics in the symmetric case of N equal-quality nests. Then, we generalize our findings to a best-of-N decision scenario with one superior nest and N -1 inferior nests, previously studied empirically in bees and ants. Whereas previous binary models highlighted the crucial role of inhibitory stop-signaling, the key parameter in our new analysis is the relative time invested by swarm members in individual discovery and in signaling behaviors. Our new analysis reveals conflicting pressures on this ratio in symmetric and best-of-N decisions, which could be solved through a time-dependent signaling strategy. Additionally, our analysis suggests how ecological factors determining the density of suitable nest sites may have led to selective pressures for an optimal stable signaling ratio.

Greater sage-grouse nest predators in the Virginia Mountains of northwestern Nevada

Science.gov (United States)

Lockyer, Zachary B.; Coates, Peter S.; Casazza, Michael L.; Espinosa, Shawn; Delehanty, David J.

2013-01-01

Greater sage-grouse Centrocercus urophasianus, hereafter sage-grouse, populations have declined across their range due to the loss, degradation, and fragmentation of habitat. Habitat alterations can lead not only to vegetative changes but also to shifts in animal behavior and predator composition that may influence population vital rates, such as nest success. For example, common ravens Corvus corax are sage-grouse nest predators, and common raven abundance is positively associated with human-caused habitat alterations. Because nest success is a central component to sage-grouse population persistence, research that identifies factors influencing nest success will better inform conservation efforts. We used videography to unequivocally identify sage-grouse nest predators within the Virginia Mountains of northwestern Nevada, USA, from 2009 to 2011 and used maximum likelihood to calculate daily probability of nest survival. In the Virginia Mountains, fires, energy exploration, and other anthropogenic activities have altered historic sage-grouse habitat. We monitored 71 sage-grouse nests during the study, placing video cameras at 39 nests. Cumulative nest survival for all nests was 22.4% (95% CI, 13.0–33.4%), a survival rate that was significantly lower than other published results for sage-grouse in the Great Basin. Depredation was the primary cause for nest failure in our study (82.5%), and common ravens were the most frequent sage-grouse nest predator, accounting for 46.7% of nest depredations. We also successfully documented a suite of mammalian and reptilian species depredating sage-grouse nests, including some predators never previously confirmed in the literature to be sage-grouse nest predators (i.e., bobcats Lynx rufus and long-tailed weasels Mephitis frenata). Within the high elevation, disturbed habitat of the Virginia Mountains, low sage-grouse nest success may be limiting sage-grouse population growth. These results suggest that management actions that

Nesting ecology of Nile crocodiles (Crocodylus niloticus in the Olifants River, Kruger National Park

Directory of Open Access Journals (Sweden)

D.G.J. Swanepoel

2000-07-01

Full Text Available Data on the nesting behaviour of Crocodylus niloticus along the Olifants River in the Kruger National Park were collected over a period of six years (1993 to 1998. A total of 165 nests were investigated for soil type, exposure to sunlight, distance to and above water, presence of other nests and vegetation. An attempt was made to determine important factors in the placement of nests, and exposure to sunlight, vegetation and distance to water seemed to be crucial in selecting a nesting site. During the last two seasons 20 nests were opened and the nest contents recorded. Some 795 eggs were measured and the data compared to similar studies in Africa. No significant differences were found. A strong correlation was found between egg mass, length and female size with larger females producing larger eggs. Rainfall influenced the size of nesting females as only larger females (>3 m TL nested during the dry year. Breeding females along the Olifants were overall larger (TL than in Zimbabwe with 2.1 m as the smallest and 4.1 as the largest females that nested.

Factors affecting farm diversification in rice-wheat

International Nuclear Information System (INIS)

Ashfaq, M.; Hassan, S.; Naseer, M.Z.; Baig, I.A.; Asma, J.

2008-01-01

The risk in agriculture sector is due to various factors like weather and market conditions, particularly the demand of the commodities. This uncertainty can result in variable returns (farm income) to the decisions that farmers make in a particular season. Diversification is a frequently used risk management strategy that involves participation in more than one activity. It has the added advantage of mitigating price risk as well as fluctuations in outputs. The main purpose of this paper was to determine the factors affecting crop diversification. For determining the effect of different factors on diversification a multiple regression model was used. The values of Entropy index computed for measuring horizontal diversification were taken as dependent variable and different factors affecting diversification were taken as independent variables. The results showed that the main factors affecting diversification were size of land holding, age of respondent, education level of respondent, farming experience of respondent, off farm income of respondent, distance of farm from main road, distance of farm from main market and farm machinery. (author)

Nesting ecology of Townsend's warblers in relation to habitat characteristics in a mature boreal forest

Science.gov (United States)

Matsuoka, S.M.; Handel, Colleen M.; Roby, D.D.

1997-01-01

We investigated the nesting ecology of Townsend's Warblers (Dendroica townsendi) from 1993-1995 in an unfragmented boreal forest along the lower slopes of the Chugach Mountains in southcentral Alaska. We examined habitat characteristics of nest sites in relation to factors influencing reproductive success. Almost all territory-holding males (98%, n = 40) were successful in acquiring mates. Nest success was 54% (n = 24 nests), with nest survivorship greater during incubation (87%) than during the nestling period (62%). Most nesting failure (80%) was attributable to predation, which occurred primarily during the nestling period. Fifty-five percent of nests containing nestling were infested with the larvae of bird blow-flies (Protocalliphora braueri and P. spenceri), obligatory blood-feeding parasites. The combined effects of Protocalliphora infestation and inclement weather apparently resulted in nestling mortality in 4 of the 24 nests. Nests that escaped predation were placed in white spruce with larger diameter than those lost to predation: nests that escaped blow-fly parasitism were located higher in nest trees and in areas with lower densities of woody shrubs than those that were infested. The availability of potential nest sites with these key features may be important in determining reproductive success in Townsend's Warblers.

Parental investment decisions in response to ambient nest-predation risk versus actual predation on the prior nest

Science.gov (United States)

Chalfoun, A.D.; Martin, T.E.

2010-01-01

Theory predicts that parents should invest less in dependent offspring with lower reproductive value, such as those with a high risk of predation. Moreover, high predation risk can favor reduced parental activity when such activity attracts nest predators. Yet, the ability of parents to assess ambient nest-predation risk and respond adaptively remains unclear, especially where nest-predator assemblages are diverse and potentially difficult to assess. We tested whether variation in parental investment by a multi-brooded songbird (Brewer's Sparrow, Spizella breweri) in an environment (sagebrush steppe) with diverse predators was predicted by ambient nest-predation risk or direct experience with nest predation. Variation among eight sites in ambient nest-predation risk, assayed by daily probabilities of nest predation, was largely uncorrelated across four years. In this system risk may therefore be unpredictable, and aspects of parental investment (clutch size, egg mass, incubation rhythms, nestling-feeding rates) were not related to ambient risk. Moreover, investment at first nests that were successful did not differ from that at nests that were depredated, suggesting parents could not assess and respond to territorylevel nest-predation risk. However, parents whose nests were depredated reduced clutch sizes and activity at nests attempted later in the season by increasing the length of incubation shifts (on-bouts) and recesses (off-bouts) and decreasing trips to feed nestlings. In this unpredictable environment parent birds may therefore lack sufficient cues of ambient risk on which to base their investment decisions and instead rely on direct experience with nest predation to inform at least some of their decisions. ?? 2010 The Cooper Ornithological Society.

Landscape forest cover and edge effects on songbird nest predation vary by nest predator

Science.gov (United States)

W. Andrew Cox; Frank R. III Thompson; John. Faaborg

2012-01-01

Rates of nest predation for birds vary between and within species across multiple spatial scales, but we have a poor understanding of which predators drive such patterns. We video-monitored nests and identified predators at 120 nests of the Acadian Flycatcher (Empidonax virescens) and the Indigo Bunting (Passerina cyanea) at eight...

Nest Material Shapes Eggs Bacterial Environment.

Directory of Open Access Journals (Sweden)

Cristina Ruiz-Castellano

Full Text Available Selective pressures imposed by pathogenic microorganisms to embryos have selected in hosts for a battery of antimicrobial lines of defenses that includes physical and chemical barriers. Due to the antimicrobial properties of volatile compounds of green plants and of chemicals of feather degrading bacteria, the use of aromatic plants and feathers for nest building has been suggested as one of these barriers. However, experimental evidence suggesting such effects is scarce in the literature. During two consecutive years, we explored experimentally the effects of these nest materials on loads of different groups of bacteria (mesophilic bacteria, Enterobacteriaceae, Staphylococcus and Enterococcus of eggshells in nests of spotless starlings (Sturnus unicolor at the beginning and at the end of the incubation period. This was also explored in artificial nests without incubation activity. We also experimentally increased bacterial density of eggs in natural and artificial nests and explored the effects of nest lining treatments on eggshell bacterial load. Support for the hypothetical antimicrobial function of nest materials was mainly detected for the year and location with larger average values of eggshell bacterial density. The beneficial effects of feathers and plants were more easily detected in artificial nests with no incubation activity, suggesting an active role of incubation against bacterial colonization of eggshells. Pigmented and unpigmented feathers reduced eggshell bacterial load in starling nests and artificial nest boxes. Results from artificial nests allowed us to discuss and discard alternative scenarios explaining the detected association, particularly those related to the possible sexual role of feathers and aromatic plants in starling nests. All these results considered together confirm the antimicrobial functionality mainly of feathers but also of plants used as nest materials, and highlight the importance of temporally and

Nest Material Shapes Eggs Bacterial Environment.

Science.gov (United States)

Ruiz-Castellano, Cristina; Tomás, Gustavo; Ruiz-Rodríguez, Magdalena; Martín-Gálvez, David; Soler, Juan José

2016-01-01

Selective pressures imposed by pathogenic microorganisms to embryos have selected in hosts for a battery of antimicrobial lines of defenses that includes physical and chemical barriers. Due to the antimicrobial properties of volatile compounds of green plants and of chemicals of feather degrading bacteria, the use of aromatic plants and feathers for nest building has been suggested as one of these barriers. However, experimental evidence suggesting such effects is scarce in the literature. During two consecutive years, we explored experimentally the effects of these nest materials on loads of different groups of bacteria (mesophilic bacteria, Enterobacteriaceae, Staphylococcus and Enterococcus) of eggshells in nests of spotless starlings (Sturnus unicolor) at the beginning and at the end of the incubation period. This was also explored in artificial nests without incubation activity. We also experimentally increased bacterial density of eggs in natural and artificial nests and explored the effects of nest lining treatments on eggshell bacterial load. Support for the hypothetical antimicrobial function of nest materials was mainly detected for the year and location with larger average values of eggshell bacterial density. The beneficial effects of feathers and plants were more easily detected in artificial nests with no incubation activity, suggesting an active role of incubation against bacterial colonization of eggshells. Pigmented and unpigmented feathers reduced eggshell bacterial load in starling nests and artificial nest boxes. Results from artificial nests allowed us to discuss and discard alternative scenarios explaining the detected association, particularly those related to the possible sexual role of feathers and aromatic plants in starling nests. All these results considered together confirm the antimicrobial functionality mainly of feathers but also of plants used as nest materials, and highlight the importance of temporally and geographically

Design of nest access grids and perches in front of the nests: Influence on the behavior of laying hens.

Science.gov (United States)

Stämpfli, K; Buchwalder, T; Fröhlich, E K F; Roth, B A

2013-04-01

In aviary systems for laying hens, it is important to provide suitable nest access platforms in front of the nests, allowing hens to reach and explore each of the nests easily. This access platform is needed to achieve good nest acceptance by the hens and thereby prevent mislaid eggs. In the present experiment, the behavior of hens using 2 different nest access platforms, a plastic grid and 2 wooden perches, was examined. Furthermore, the nests were placed on both sides of the aviary rack (corridor side and outdoor side), either integrated into the aviary rack itself (integrated nest; IN) or placed on the walls of the pens (wall nest; WN), resulting in a 2 × 2 factorial design Four thousand five hundred white laying hens were housed in 20 test pens. The eggs in the nests and mislaid eggs were collected daily, and the behavior of hens on the nest accesses was filmed during wk 25 and 26, using focal observation and scan sampling methods. More balancing, body contact, and agonistic interactions were expected for nests with perches, whereas more walking and nest inspections were expected for nests with grids. There were more mislaid eggs and balancing found in pens equipped with nests with wooden perches. More agonistic interactions and balancing, less standing, and a longer duration of nest inspection were found with the WN compared with the IN. Interactions between platform design and position of the nests were found for duration of nest visits, body contact, and walking, with the highest amount for WN equipped with plastic grids. Nests on the corridor side were favored by the hens. Nest-related behaviors, such as nest inspection, standing, and walking, decreased over time as did the number of hens on the nest accesses, whereas sitting increased. These results indicate that the hens had more difficulties in gripping the perches as designed. The lower number of hens on the nest access platforms in front of IN may be due to a better distribution around nests and tier

Bee species-specific nesting material attracts a generalist parasitoid: implications for co-occurring bees in nest box enhancements.

Science.gov (United States)

Macivor, J Scott; Salehi, Baharak

2014-08-01

Artificial nests (e.g., nest boxes) for bees are increasingly being used to contribute to nesting habitat enhancement for bees that use preexisting cavities to provision brood. They usually incorporate additional nesting materials that vary by species. Cavity-nesting bees are susceptible to brood parasitoids that recognize their host(s) using visual and chemical cues. Understanding the range of cues that attract parasitoids to bee nests, including human-made analogues, is important if we wish to control parasitism and increase the potential value of artificial nests as habitat-enhancement strategies. In this study, we investigated the cues associated with the orientation of the generalist brood parasitoid Monodontomerus obscurus Westwood (Hymenoptera: Torymidae) to the nests of a common cavity-nesting resin bee Megachile campanulae (Robertson) (Megachilidae). The parasitoids were reared from previously infested M. campanulae brood cells and placed into choice trials where they were presented with pairs of different nest material cues. Among different materials tested, we found that Mo. obscurus was most attracted to fresh resin collected directly from Pinus strobus trees followed by previously used resin collected from the bee nest. The parasitoid also attacked other bee species in the same nest boxes, including those that do not use resin for nesting. Our findings suggest that M. campanulae could act as a magnet, drawing parasites away from other bee hosts co-occurring in nest boxes, or, as an attractant of Mo. obscurus to nest boxes, increasing attacks on co-occurring host bee species, potentially undermining bee diversity enhancement initiatives.

Nested Potential Games

OpenAIRE

Hiroshi Uno

2007-01-01

This paper proposes a new class of potential games, the nested potential games, which generalize the potential games defined in Monderer and Shapley (1996), as well as the pseudo-potential games defined in Dubey et al. (2006). We show that each maximizer of a nested potential is a Nash equilibrium.

Nesting ecology and nest survival of lesser prairie-chickens on the Southern High Plains of Texas

Science.gov (United States)

Grisham, Blake A.; Borsdorf, Philip K.; Boal, Clint W.; Boydston, Kathy K.

2014-01-01

The decline in population and range of lesser prairie-chickens (Tympanuchus pallidicinctus) throughout the central and southern Great Plains has raised concerns considering their candidate status under the United States Endangered Species Act. Baseline ecological data for lesser prairie-chickens are limited, especially for the shinnery oak-grassland communities of Texas. This information is imperative because lesser prairie-chickens in shinnery oak grasslands occur at the extreme southwestern edge of their distribution. This geographic region is characterized by hot, arid climates, less fragmentation, and less anthropogenic development than within the remaining core distribution of the species. Thus, large expanses of open rangeland with less anthropogenic development and a climate that is classified as extreme for ground nesting birds may subsequently influence nest ecology, nest survival, and nest site selection differently compared to the rest of the distribution of the species. We investigated the nesting ecology of 50 radio-tagged lesser prairie-chicken hens from 2008 to 2011 in the shinnery oak-grassland communities in west Texas and found a substantial amount of inter-annual variation in incubation start date and percent of females incubating nests. Prairie-chickens were less likely to nest near unimproved roads and utility poles and in areas with more bare ground and litter. In contrast, hens selected areas dominated by grasses and shrubs and close to stock tanks to nest. Candidate models including visual obstruction best explained daily nest survival; a 5% increase in visual obstruction improved nest survival probability by 10%. The model-averaged probability of a nest surviving the incubation period was 0.43 (SE = 0.006; 95% CI: 0.23, 0.56). Our findings indicate that lesser prairie-chicken reproduction during our study period was dynamic and was correlated with seasonal weather patterns that ultimately promoted greater grass growth earlier in the

Comparative population structure of cavity-nesting sea ducks

Science.gov (United States)

Pearce, John M.; Eadie, John M.; Savard, Jean-Pierre L.; Christensen, Thomas K.; Berdeen, James; Taylor, Eric J.; Boyd, Sean; Einarsson, Árni

2014-01-01

A growing collection of mtDNA genetic information from waterfowl species across North America suggests that larger-bodied cavity-nesting species exhibit greater levels of population differentiation than smaller-bodied congeners. Although little is known about nest-cavity availability for these species, one hypothesis to explain differences in population structure is reduced dispersal tendency of larger-bodied cavity-nesting species due to limited abundance of large cavities. To investigate this hypothesis, we examined population structure of three cavity-nesting waterfowl species distributed across much of North America: Barrow's Goldeneye (Bucephala islandica), Common Goldeneye (B. clangula), and Bufflehead (B. albeola). We compared patterns of population structure using both variation in mtDNA control-region sequences and band-recovery data for the same species and geographic regions. Results were highly congruent between data types, showing structured population patterns for Barrow's and Common Goldeneye but not for Bufflehead. Consistent with our prediction, the smallest cavity-nesting species, the Bufflehead, exhibited the lowest level of population differentiation due to increased dispersal and gene flow. Results provide evidence for discrete Old and New World populations of Common Goldeneye and for differentiation of regional groups of both goldeneye species in Alaska, the Pacific Northwest, and the eastern coast of North America. Results presented here will aid management objectives that require an understanding of population delineation and migratory connectivity between breeding and wintering areas. Comparative studies such as this one highlight factors that may drive patterns of genetic diversity and population trends.

Nesting ecology of Podocnemis expansa (Schweigger, 1812 and Podocnemis unifilis (Troschel, 1848 (Testudines, Podocnemididae in the Javaés River, Brazil

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PD. Ferreira Júnior

Full Text Available Nest site has influence on incubation duration and hatching success of two Neotropical turtles, the Giant Amazon River Turtle (Podocnemis expansa and Yellow-Spotted Side-Neck Turtle (Podocnemis unifilis - "Tracajá". The 2000 and 2001 nesting seasons have been monitored at the Javaés River in Bananal Island, Brazil. Although they nest on the same beaches, there is a separation of the nesting areas of P unifilis and P. expansa nests on the upper parts of the beach. The incubation duration for P. expansa is influenced by the nesting period, the height of the nest from the river, the clutch size, and the grain size in the site of the nest. Nests of Podocnemis expansa placed in coarse sediments have shorter incubation duration than those placed in finer sediments. The hatching success in P. expansa is influenced by grain size, incubation duration, and nesting period. The grain size is negatively correlated with hatching success, indicating that the nests situated in finer-grained sand have better chances of successful egg hatching than those in coarser-grained sand. Nests of the end of the reproductive season have lower hatching success and incubation duration than those at the start of the season. For P. unifilis, the nesting period and nest depth influence the incubation duration; moreover, the river dynamics significantly affect the hatching success. The oscillation of the river level and the moment of initial increase, the height of the nest from the river level, and the nesting period are all decisive components for hatching success. The results of this research show the importance of protecting areas with great geological diversity, wherein the features of the environment can affect the microenvironment of nests, with consequences on incubation duration and hatching success.

Differences in predators of artificial and real songbirds nests: Evidence of bias in artificial nest studies

Science.gov (United States)

Frank R. Thompson; Dirk E. Burhans

2004-01-01

In the past two decades, many researchers have used artificial nest to measure relative rates of nest predation. Recent comparisons show that real and artificial nests may not be depredated at the same rate, but no one has examined the mechanisms underlying these patterns. We determined differences in predator-specific predation rates of real and artificial nests. we...

Conservation significance of alternative nests of golden eagles

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Brian A. Millsap

2015-01-01

Full Text Available Golden eagles (Aquila chrysaetos are long-lived raptors that maintain nesting territories that may be occupied for a century or longer. Within occupied nesting territories there is one nest in which eagles lay their eggs in a given year (i.e., the used nest, but there are usually other nests (i.e., alternative nests. Conservation plans often protect used nests, but not alternative nests or nesting territories that appear vacant. Our objective is to review literature on golden eagle use of alternative nests and occupancy of nesting territories to determine if alternative nests are biologically significant and warrant greater conservation consideration. Our review shows that: (1 alternative nests or their associated habitat are most often in core areas of golden eagle nesting territories; (2 alternative nests likely will become used in the future; (3 probability of an alternative nest becoming used is greatest where prey availability is high and alternative nest sites are limited; (4 likelihood of annual occupancy or reoccupancy of golden eagle nesting territories is high; and (5 prey availability is the most important determinant of nesting territory occupancy and breeding activity. We recommend alternative nests be treated with the same deference as used nests in land use planning.

Influence of fluoride exhalates in the vicinity of the aluminum foundry in Ziar had Hronom on the number of nesting birds

Energy Technology Data Exchange (ETDEWEB)

Feriancova-Masarova, Z; Kalivodova, E

1965-01-01

The number of nesting birds in 3 areas was studied and compared to the number of birds nesting in an area free of fluoride exhalates. The nesting is most adversely affected in the first area, where trees die out due to a continuous, massive influence of the fluoride exhalates. The bird population of this area leaves to nest in the second or third area, causing a considerable increase in the nesting population of those two localities.

Columbia River ESI: NESTS (Nest Points)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for bird nesting sites in the Columbia River area. Vector points in this data set represent locations of...

Changes in position and quality of preferred nest box: effects on nest box use by laying hens

DEFF Research Database (Denmark)

Riber, Anja Brinch; Nielsen, Birte L.

2013-01-01

Using laying hens, we investigated whether position of a nest box, both within the pen and relative to other nest boxes, influenced the preference for a nest box, and how a sudden and marked change to the preferred box influenced the use of nest boxes by the hens. Groups (n=12) of 15 Isa Warren...... hens were housed in pens, each with five identical nest boxes in different positions: Two single (in a corner or not) and a triplet of nest boxes (one of which in a corner). The use of nest boxes was determined by the number of eggs laid daily in each box. Three experiments, each lasting 10 days, were...... carried out. First, the undisturbed use of each of the nest box types was investigated, and a strong preference (Peggs laid there. Second, each of the hen groups was moved to another pen allocated at random, and where...

Living with aliens: effects of invasive shrub honeysuckles on avian nesting.

Directory of Open Access Journals (Sweden)

Jason M Gleditsch

Full Text Available Invasive species have come to the forefront of conservation biology as a major threat to native biodiversity. Habitats dominated by shrub honeysuckles (Lonicera spp. in the United States have been characterized as "ecological traps" by ecologists. Here we tested this hypothesis by investigating the effects of shrub honeysuckles on the nesting ecology of native birds in seven study sites in central Pennsylvania, USA. We examined how the abundance of shrub honeysuckles influenced the selection of nesting substrates and habitat for a community of common songbirds, and the parental-care behavior and nestling development of gray catbirds (Dumetella carolinensis. We found that birds had a strong bias towards nesting in honeysuckle shrubs, but not necessarily for nesting in honeysuckle-dominated habitats. Nest predation rates were affected by the density of nests in a habitat, but not by the overall abundance of honeysuckles in such habitats. Honeysuckle abundance in the habitat did show significant effects on some parental-care behavioral parameters: catbirds had higher nest visitation rates and shorter visit lengths in areas of high honeysuckle density. On average, Gray catbirds fed fruit 12%±0.31 s.e. of their nestling-feeding bouts, mostly fruits of shrub honeysuckles. Nestlings in sites with high honeysuckle density also showed higher mass:tarsus ratios, suggesting a good (possibly better physiological condition of catbird nestlings at the time of fledging. Our study shows that honeysuckle-dominated habitats could have equivocal effects on nesting parameters of common species of native birds. We advise more caution in the widespread denomination of novel plant communities with high densities of honeysuckle as "ecological traps" as effects can be null or positive on native birds in certain localities.

Age Learning Factors Affecting Pilot Education.

Science.gov (United States)

Torbert, Brison

This document, intended for pilot education and flight safety specialists, consists chiefly of a review of the literature on physiological factors that affect pilot education and an examination of environmental factors that should be scrutinized in order to improve the effectiveness of aviation learning facilities. The physiological factors…

Perceived Factors Affecting Performance Of Extension Workers In ...

African Journals Online (AJOL)

The study focused on perceived factors affecting performance of extension workers in Imo State, Nigeria. Data for the study was collected from 83 Extension agents from the Imo State Agricultural Development Programme (ADP). Results of the study revealed that the organizational factors that affect performance are ...

Lack of nest site limitation in a cavity-nesting bird community

Science.gov (United States)

Jeffry R. Waters; Barry R. Noon; Jared Verner

1990-01-01

We examined the relationship between nest site availability and density of secondary cavitynesting birds by blocking cavities in an oak-pine (Quercus spp.-Pinus sp. ) woodland. In 1986 and 1987we blocked 67 and 106 cavities, respectively, on a 37-ha plot. The combined density of secondary cavity-nesting birds did not decline...

Nesting biology of Trypoxylon (Trypargilum) lactitarse Saussure (Hymenoptera, Crabronidae) in trap-nests in Southern Brazil.

Science.gov (United States)

Buschini, M L T; Niesing, F; Wolff, L L

2006-08-01

This study was carried in the Parque Municipal das Araucárias in the municipality of Guarapuava, state of Paraná, Southern Brazil. Three hundred and sixty five nests of T. lactitarse were obtained using trap-nests of 0.7, 1.0, and 1.3 cm in diameter. All of them had similar architecture, regardless of the diameter of the trap-nest. Completed nests consisted of a linear series of brood cells whose average number per nest was of 3.3, 4.0 and 3.6 for the nests with 0.7 cm, 1.0 cm and 1.3 cm in diameter, respectively. They were constructed more often during the summer. T. lactitarse had two types of life cycles: direct development (without diapause), and delayed development (with diapause during winter). Natural enemies included Chrysididae, Sarcophagidae, Dolichopodidae and Ichneumonidae. Out of 1,353 identified spider prey, 1,313 belonged to the Araneidae family.

Nesting biology of Trypoxylon (Trypargilum lactitarse Saussure (Hymenoptera, Crabronidae in trap-nests in Southern Brazil

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M. L. T. Buschini

Full Text Available This study was carried in the Parque Municipal das Araucárias in the municipality of Guarapuava, state of Paraná, Southern Brazil. Three hundred and sixty five nests of T. lactitarse were obtained using trap-nests of 0.7, 1.0, and 1.3 cm in diameter. All of them had similar architecture, regardless of the diameter of the trap-nest. Completed nests consisted of a linear series of brood cells whose average number per nest was of 3.3, 4.0 and 3.6 for the nests with 0.7 cm, 1.0 cm and 1.3 cm in diameter, respectively. They were constructed more often during the summer. T. lactitarse had two types of life cycles: direct development (without diapause, and delayed development (with diapause during winter. Natural enemies included Chrysididae, Sarcophagidae, Dolichopodidae and Ichneumonidae. Out of 1,353 identified spider prey, 1,313 belonged to the Araneidae family.

Reproductive Consequences of Nest Site Use in Fork-tailed Storm-Petrels in the Aleutian Islands, Alaska: Potential Lasting Effects of an Introduced Predator

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Brie A. Drummond

2010-12-01

Full Text Available We examined the reproductive consequences of differential nest site use in Fork-tailed Storm-Petrels (Oceanodroma furcata in the Aleutian Islands, Alaska, where birds on islands where foxes were introduced nest in rocky substrate rather than in typical soil habitat. We investigated how physical and microclimatic nest site characteristics influenced storm-petrel breeding success 20 years after fox removal. We then examined whether those nest site characteristics that affected success were related to the amount of rock that composed the nest. In both years of our study, nest temperature had the strongest influence on chick survival and overall reproductive success, appearing in all the top models and alone explaining 14-35% of the variation in chick survival. The relationship between reproductive success and nest temperature was positive in both years, with higher survival in warmer nests. In turn, the best predictor of nest temperature was the amount of rock that composed the site. Rockier nests had colder average temperatures, which were driven by lower daily minimum temperatures, compared to nests with more soil. Thus, the rockiness of the nest site appeared to affect chick survival and overall reproductive success through its influence on nest temperature. This study suggests that the use of rocky nest sites, presumed to be a result of historic predation from introduced foxes, could decrease breeding success in this recovering population, and thus be a long-lasting effect of introduced predators.

Diagnostic value of nested-PCR for identification of Malassezia species in dandruff

Science.gov (United States)

Jusuf, N. K.; Nasution, T. A.; Ullyana, S.

2018-03-01

Dandruff or pityriasis simplex is a condition of abnormal occurrence of formation of yellowish white scales from the scalp. Many factors play a role in the pathogenesis of dandruff, i.e.colonization of Malassezia species. Examination of Malassezia species previously done by culture as the gold standard. However, there are various difficulties in doing the culture. Identification method with anested-polymerase chain reaction (nested-PCR) is expected to provide quickly and easily detected. This study aimedto determine the diagnostic value of nested-PCR in the identification of Malassezia species in dandruff. From 21 subjects, scales from the scalp were taken and sent to the laboratory for nested-PCR identification. Statistical analysis of diagnostic test carried out to determine sensitivity, specificity, positive predictive value, and negative predictive value. The results showed nested-PCR detected 10 sample (47.6%) positive for Malassezia species consist of M. sympodialis (23.8%); M. slooffiae (9.5%); M. furfur (4.8%); M. globosa and M. furfur (4.8%); and M. restricta and M. sympodialis (4.8%). Detection of Malassezia species by nested-PCR has 100% in sensitivity whereas the specificity was 55%. Nested-PCR test has high sensitivity. Therefore nested-PCR may be considered for a faster and simpler alternative examination in identification for Malassezia species in dandruff.

Decoration Increases the Conspicuousness of Raptor Nests.

Science.gov (United States)

Canal, David; Mulero-Pázmány, Margarita; Negro, Juan José; Sergio, Fabrizio

2016-01-01

Avian nests are frequently concealed or camouflaged, but a number of species builds noticeable nests or use conspicuous materials for nest decoration. In most cases, nest decoration has a role in mate choice or provides thermoregulatory or antiparasitic benefits. In territorial species however, decorations may serve additional or complementary functions, such as extended phenotypic signaling of nest-site occupancy and social status to potential intruders. The latter may benefit both signaler and receiver by minimizing the risk of aggressive interactions, especially in organisms with dangerous weaponry. Support for this hypothesis was recently found in a population of black kites (Milvus migrans), a territorial raptor that decorates its nest with white artificial materials. However, the crucial assumption that nest decorations increased nest-site visibility to conspecifics was not assessed, a key aspect given that black kite nests may be well concealed within the canopy. Here, we used an unmanned aircraft system to take pictures of black kite nests, with and without an experimentally placed decoration, from different altitudes and distances simulating the perspective of a flying and approaching, prospecting intruder. The pictures were shown to human volunteers through a standardized routine to determine whether detection rates varied according the nest decoration status and distance. Decorated nests consistently showed a higher detection frequency and a lower detection-latency, compared to undecorated versions of the same nests. Our results confirm that nest decoration in this species may act as a signaling medium that enhances nest visibility for aerial receivers, even at large distances. This finding complements previous work on this communication system, which showed that nest decoration was a threat informing trespassing conspecifics on the social dominance, territory quality and fighting capabilities of the signaler.

ANALYSIS OF THE FACTORS AFFECTING THE AVERAGE

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Carmen BOGHEAN

2013-12-01

Full Text Available Productivity in agriculture most relevantly and concisely expresses the economic efficiency of using the factors of production. Labour productivity is affected by a considerable number of variables (including the relationship system and interdependence between factors, which differ in each economic sector and influence it, giving rise to a series of technical, economic and organizational idiosyncrasies. The purpose of this paper is to analyse the underlying factors of the average work productivity in agriculture, forestry and fishing. The analysis will take into account the data concerning the economically active population and the gross added value in agriculture, forestry and fishing in Romania during 2008-2011. The distribution of the average work productivity per factors affecting it is conducted by means of the u-substitution method.

Synchronised provisioning at the nest: parental coordination over care in a socially monogamous species.

Science.gov (United States)

van Rooij, Erica P; Griffith, Simon C

2013-12-19

Bi-parental care is very common in birds, occurring in over 90% of species, and is expected to evolve whenever the benefits of enhanced offspring survival exceed the costs to both parents of providing care. In altricial species, where the nestlings are entirely dependent on the parents for providing food until fledging, reproductive success is related to the capacity of the parents to provision the offspring at the nest. The degree to which parents synchronise their visits to the nest is rarely considered by studies of bi-parental care, and yet may be an important component of parental care, affecting the outcome of the reproductive attempt, and the dynamics of sexual conflict between the parents. Here we studied this aspect of parental care in the long-tailed finch (Poephila acuticauda), a socially monogamous estrildid finch. We monitored parental nest visit rates and the degree of parental visit synchrony, and assessed their effects on reproductive success (e.g., brood size, number of offspring fledged and nestling growth). The frequency of nest visits in a day was low in this species (nest visit synchrony may primarily be driven by the benefit of parents being together whilst foraging away from the nest, or may reduce nest predation by reducing the level of activity around the nest throughout the day.

Nest defense behaviors of native cavity-nesting birds to European Starlings

Science.gov (United States)

Rodney G. Olsen; Kathryn L. Purcell; David. Grubbs

2008-01-01

We used behavioral experiments to evaluate competition for nest sites and the extent to which European Starlings (Sturnus vulgaris) are seen as a threat by native bird species at the San Joaquin Experimental Range, Madera County, CA. We quantified the level of aggressive behavior of four species of native cavity-nesting birds to starlings at active...

Interspecific nest use by aridland birds

Science.gov (United States)

Deborah M. Finch

1982-01-01

Nest holes drilled by woodpeckers (Picidae) are frequently used by secondary cavity-nesting species, but interspecific use of open and domed nests is less well known. Nests constructed by many southwestern desert birds last longer than one year (pers. obs.) and are consequently reused by the same pair (e.g., Abert's Towhees [Pipilo aberti], pers. obs.) or by other...

Ground-nesting marine birds and potential for human disturbance in Glacier Bay National Park

Science.gov (United States)

Arimitsu, Mayumi L.; Romano, Marc D.; Piatt, John F.; Piatt, John F.; Gende, S.M.

2004-01-01

Glacier Bay National Park and Preserve contains a diverse assemblage of marine birds that use the area for nesting, foraging and molting. The abundance and diversity of marine bird species in Glacier Bay is unmatched in the region, due in part to the geomorphic and successional characteristics that result in a wide array of habitat types (Robards and others, 2003). The opportunity for proactive management of these species is unique in Glacier Bay National Park because much of the suitable marine bird nesting habitat occurs in areas designated as wilderness. Ground-nesting marine birds are vulnerable to human disturbance wherever visitors can access nest sites during the breeding season. Human disturbance of nest sites can be significant because intense parental care is required for egg and hatchling survival, and repeated disturbance can result in reduced productivity (Leseberg and others, 2000). Temporary nest desertion by breeding birds in disturbed areas can lead to increased predation on eggs and hatchlings by conspecifics or other predators (Bolduc and Guillemette, 2003). Human disturbance of ground-nesting birds may also affect incubation time and adult foraging success, which in turn can alter breeding success (Verhulst and others, 2001). Furthermore, human activity can potentially cause colony failure when disturbance prevents the initiation of nesting (Hatch, 2002). There is management concern about the susceptibility of breeding birds to disturbance from human activities, but little historical data has been collected on the distribution of ground-nesting marine birds in Glacier Bay. This report summarizes results obtained during two years of a three-year study to determine the distribution of ground-nesting marine birds in Glacier Bay, and the potential for human disturbance of those nesting birds.

Environmental Factors Affecting Preschoolers' Motor Development

Science.gov (United States)

Venetsanou, Fotini; Kambas, Antonis

2010-01-01

The process of development occurs according to the pattern established by the genetic potential and also by the influence of environmental factors. The aim of the present study was to focus on the main environmental factors affecting motor development. The review of the literature revealed that family features, such as socioeconomic status,…

Community structure variability of Uropodina mites (Acari: Mesostigmata) in nests of the common mole, Talpa europaea, in Central Europe.

Science.gov (United States)

Napierała, Agnieszka; Mądra, Anna; Leszczyńska-Deja, Kornelia; Gwiazdowicz, Dariusz J; Gołdyn, Bartłomiej; Błoszyk, Jerzy

2016-04-01

Underground nests of Talpa europaea, known as the common mole, are very specific microhabitats, which are also quite often inhabited by various groups of arthropods. Mites from the suborder Uropodina (Acari: Mesostigmata) are only one of them. One could expect that mole nests that are closely located are inhabited by communities of arthropods with similar species composition and structure. However, results of empirical studies clearly show that even nests which are close to each other can be different both in terms of the species composition and abundance of Uropodina communities. So far, little is known about the factors that can cause these differences. The major aim of this study was to identify factors determining species composition, abundance, and community structure of Uropodina communities in mole nests. The study is based on material collected during a long-term investigation conducted in western parts of Poland. The results indicate that the two most important factors influencing species composition and abundance of Uropodina communities in mole nests are nest-building material and depth at which nests are located. Composition of Uropodina communities in nests of moles was also compared with that of other microhabitats (e.g. rotten wood, forest litter, soil) based on data from 4421 samples collected in Poland. Communities of this habitat prove most similar to these of open areas, especially meadows, as well as some forest types.

Nesting biology of the trap-nesting Neotropical wasp Trypoxylo n(Trypargilum) aurifrons Shuckard (Hymenoptera, Crabronidae)

OpenAIRE

Santoni,Mariana Marchi; Del Lama,Marco Antonio

2007-01-01

The present study was carried out in three localities of the state of São Paulo, Brazil: Araras (Dec/03-Dec/06), São Carlos (Nov/04-Nov/06) and Rifaina (Jul/04-Dec/06). Trap-nests were distributed among sites in the sampling areas and were collected every 35 days. Data from 295 nests indicate that T. aurifrons is a multivoltine species, with higher rates of nest building and cell production in the warm, rainy season. The trap-nests used by the females ranged from 117 to 467 mm in length and 3...

Contrasting patterns of nest survival and postfledging survival in ovenbirds and Acadian flycatchers in Missouri forest fragments

Science.gov (United States)

Julianna M. A. Jenkins; Frank R. Thompson; John Faaborg

2016-01-01

We can improve our ability to assess population viability and forecast population growth under different scenarios by understanding factors that limit population parameters in each stage of the annual cycle. Postfledging mortality rates may be as variable as nest survival across regions and fragmentation gradients, although factors that negatively impact nest survival...

Preliminary evaluation of a nest usage sensor to detect double nest occupations of laying hens.

Science.gov (United States)

Zaninelli, Mauro; Costa, Annamaria; Tangorra, Francesco Maria; Rossi, Luciana; Agazzi, Alessandro; Savoini, Giovanni

2015-01-26

Conventional cage systems will be replaced by housing systems that allow hens to move freely. These systems may improve hens' welfare, but they lead to some disadvantages: disease, bone fractures, cannibalism, piling and lower egg production. New selection criteria for existing commercial strains should be identified considering individual data about laying performance and the behavior of hens. Many recording systems have been developed to collect these data. However, the management of double nest occupations remains critical for the correct egg-to-hen assignment. To limit such events, most systems adopt specific trap devices and additional mechanical components. Others, instead, only prevent these occurrences by narrowing the nest, without any detection and management. The aim of this study was to develop and test a nest usage "sensor", based on imaging analysis, that is able to automatically detect a double nest occupation. Results showed that the developed sensor correctly identified the double nest occupation occurrences. Therefore, the imaging analysis resulted in being a useful solution that could simplify the nest construction for this type of recording system, allowing the collection of more precise and accurate data, since double nest occupations would be managed and the normal laying behavior of hens would not be discouraged by the presence of the trap devices.

Preliminary Evaluation of a Nest Usage Sensor to Detect Double Nest Occupations of Laying Hens

Directory of Open Access Journals (Sweden)

Mauro Zaninelli

2015-01-01

Full Text Available Conventional cage systems will be replaced by housing systems that allow hens to move freely. These systems may improve hens’ welfare, but they lead to some disadvantages: disease, bone fractures, cannibalism, piling and lower egg production. New selection criteria for existing commercial strains should be identified considering individual data about laying performance and the behavior of hens. Many recording systems have been developed to collect these data. However, the management of double nest occupations remains critical for the correct egg-to-hen assignment. To limit such events, most systems adopt specific trap devices and additional mechanical components. Others, instead, only prevent these occurrences by narrowing the nest, without any detection and management. The aim of this study was to develop and test a nest usage “sensor”, based on imaging analysis, that is able to automatically detect a double nest occupation. Results showed that the developed sensor correctly identified the double nest occupation occurrences. Therefore, the imaging analysis resulted in being a useful solution that could simplify the nest construction for this type of recording system, allowing the collection of more precise and accurate data, since double nest occupations would be managed and the normal laying behavior of hens would not be discouraged by the presence of the trap devices.

Nest densities of cavity-nesting birds in relation to postfire salvage logging and time since wildfire

Science.gov (United States)

Victoria A. Saab; Robin E. Russell; Jonathan G. Dudley

2007-01-01

We monitored the nest densities and nest survival of seven cavity-nesting bird species, including four open-space foragers (American Kestrel [Falco sparverius], Lewis's Woodpecker [Melanerpes lewis], Western Bluebird [Sialia mexicana], and Mountain Bluebird [S. currucoides]) and three wood...

The relationship between affective factors and the academic ...

African Journals Online (AJOL)

The purpose of this study is to investigate the relationship between affective factors and the academic achievement of students at the University of Venda. To this end, self-concept, motivation and attitude are the affective factors selected for the study. The general aim of the study is to determine the role of self-concept, ...

Nesting ecology of Arctic loons

Science.gov (United States)

Petersen, Margaret R.

1979-01-01

Arctic Loons were studied on the Yukon-Kuskokwim Delta, Alaska, from the time of their arrival in May to their departure in September, in 1974 and 1975. Pairs arrived on breeding ponds as soon as sufficient meltwater was available to allow their take-off and landing. Loons apparently do not initiate nests immediately after their arrival, even when nest-sites are available. Delayed egg-laying may be dependent on a period of yolk formation. Delaying yolk formation until after arrival on nest ponds is an adaptation by loons to the variable time suitable habitat becomes available for nesting. Predation of eggs by Glaucous Gulls, Long-tailed and Parasitic jaegers and foxes varied in relation to the location of the nest-site, and the availability of alternate prey. Hatching success was the lowest recorded for Arctic Loons (5%) in 1974, when eggs of both loons and Cackling Geese were taken in large numbers by predators. Hatching success increased to 32% in 1975 when an abundance of tundra voles was observed. No loon eggs hatched after the hatching of the Cackling Goose eggs when this alternate prey was no longer available. Nests destroyed by foxes were predominantly along shorelines, and those by gulls and jaegers were predominantly on islands. Nest-site selection by Arctic Loons may reflect an adaptive response to varying selective pressures by their predators.

Nest-site selection in the acorn woodpecker

Science.gov (United States)

Hooge, P.N.; Stanback, M.T.; Koenig, Walter D.

1999-01-01

Acorn Woodpeckers (Melanerpes formicivorus) at Hastings Reservation in central California prefer to nest in dead limbs in large, dead valley oaks (Quercus lobata) and California sycamores (Platanus racemosa) that are also frequently used as acorn storage trees. Based on 232 nest cavities used over an 18-year period, we tested whether preferred or modal nest-site characters were associated with increased reproductive success (the "nest-site quality" hypothesis). We also examined whether more successful nests were likely to experience more favorable microclimatic conditions or to be less accessible to terrestrial predators. We found only equivocal support for the nest-site quality hypothesis: only 1 of 5 preferred characters and 2 of 10 characters exhibiting a clear modality were correlated with higher reproductive success. All three characteristics of nests known or likely to be associated with a more favorable microclimate, and two of five characteristics likely to render nests less accessible to predators, were correlated with higher reproductive success. These results suggest that nest cavities in this population are built in part to take advantage of favorable microclimatic conditions and, to a lesser extent, to reduce access to predators. However, despite benefits of particular nest characteristics, birds frequently nested in apparently suboptimal cavities. We also found a significant relationship between mean group size and the history of occupancy of particular territories and the probability of nest cavities being built in microclimatically favorable live limbs, suggesting that larger groups residing on more stable territories were better able to construct nests with optimal characteristics. This indicates that there may be demographic, as well as ecological, constraints on nest-site selection in this primary cavity nester.

Where to nest? Ecological determinants of chimpanzee nest abundance and distribution at the habitat and tree species scale.

Science.gov (United States)

Carvalho, Joana S; Meyer, Christoph F J; Vicente, Luis; Marques, Tiago A

2015-02-01

Conversion of forests to anthropogenic land-uses increasingly subjects chimpanzee populations to habitat changes and concomitant alterations in the plant resources available to them for nesting and feeding. Based on nest count surveys conducted during the dry season, we investigated nest tree species selection and the effect of vegetation attributes on nest abundance of the western chimpanzee, Pan troglodytes verus, at Lagoas de Cufada Natural Park (LCNP), Guinea-Bissau, a forest-savannah mosaic widely disturbed by humans. Further, we assessed patterns of nest height distribution to determine support for the anti-predator hypothesis. A zero-altered generalized linear mixed model showed that nest abundance was negatively related to floristic diversity (exponential form of the Shannon index) and positively with the availability of smaller-sized trees, reflecting characteristics of dense-canopy forest. A positive correlation between nest abundance and floristic richness (number of plant species) and composition indicated that species-rich open habitats are also important in nest site selection. Restricting this analysis to feeding trees, nest abundance was again positively associated with the availability of smaller-sized trees, further supporting the preference for nesting in food tree species from dense forest. Nest tree species selection was non-random, and oil palms were used at a much lower proportion (10%) than previously reported from other study sites in forest-savannah mosaics. While this study suggests that human disturbance may underlie the exclusive arboreal nesting at LCNP, better quantitative data are needed to determine to what extent the construction of elevated nests is in fact a response to predators able to climb trees. Given the importance of LCNP as refuge for Pan t. verus our findings can improve conservation decisions for the management of this important umbrella species as well as its remaining suitable habitats. © 2014 Wiley Periodicals, Inc.

Nutritional Factors Affecting Adult Neurogenesis and Cognitive Function.

Science.gov (United States)

Poulose, Shibu M; Miller, Marshall G; Scott, Tammy; Shukitt-Hale, Barbara

2017-11-01

Adult neurogenesis, a complex process by which stem cells in the hippocampal brain region differentiate and proliferate into new neurons and other resident brain cells, is known to be affected by many intrinsic and extrinsic factors, including diet. Neurogenesis plays a critical role in neural plasticity, brain homeostasis, and maintenance in the central nervous system and is a crucial factor in preserving the cognitive function and repair of damaged brain cells affected by aging and brain disorders. Intrinsic factors such as aging, neuroinflammation, oxidative stress, and brain injury, as well as lifestyle factors such as high-fat and high-sugar diets and alcohol and opioid addiction, negatively affect adult neurogenesis. Conversely, many dietary components such as curcumin, resveratrol, blueberry polyphenols, sulforaphane, salvionic acid, polyunsaturated fatty acids (PUFAs), and diets enriched with polyphenols and PUFAs, as well as caloric restriction, physical exercise, and learning, have been shown to induce neurogenesis in adult brains. Although many of the underlying mechanisms by which nutrients and dietary factors affect adult neurogenesis have yet to be determined, nutritional approaches provide promising prospects to stimulate adult neurogenesis and combat neurodegenerative diseases and cognitive decline. In this review, we summarize the evidence supporting the role of nutritional factors in modifying adult neurogenesis and their potential to preserve cognitive function during aging. © 2017 American Society for Nutrition.

Ant colonies prefer infected over uninfected nest sites

DEFF Research Database (Denmark)

Pontieri, Luigi; Vojvodic, Svjetlana; Graham, Riley

2014-01-01

with sporulating mycelium of the entomopathogenic fungus Metarhizium brunneum (infected nests), nests containing nestmates killed by freezing (uninfected nests), and empty nests. In contrast to the expectation pharaoh ant colonies preferentially (84%) moved into the infected nest when presented with the choice...... the high risk of epidemics in group-living animals. Choosing nest sites free of pathogens is hypothesized to be highly efficient in invasive ants as each of their introduced populations is often an open network of nests exchanging individuals (unicolonial) with frequent relocation into new nest sites...... and low genetic diversity, likely making these species particularly vulnerable to parasites and diseases. We investigated the nest site preference of the invasive pharaoh ant, Monomorium pharaonis, through binary choice tests between three nest types: nests containing dead nestmates overgrown...

Serenbe Nest Cottages

Energy Technology Data Exchange (ETDEWEB)

Butler, T.; Curtis, O.; Kim, E.; Roberts, S.; Stephenson, R.

2012-12-01

As part of the NAHB Research Center Industry Partnership, Southface partnered with Martin Dodson Builders and the Serenbe community on the construction of a new test home in the suburbs of Atlanta, GA in the mixed humid climate zone. The most recent subdivision within the Serenbe community, the Nest, will contain 15 small footprint cottage style homes, and Southface has selected Lot Nine, as the test home for this study. This Nest subdivision serves as a project showcase for both the builder partner and the Serenbe community as a whole. The planning and design incorporated into the Nest cottages will be implemented in each home within the subdivision. These homes addresses Building America Savings targets and serve as a basis of design for other homes Martin Dodson plans to build within the Serenbe community.

Serenbe Nest Cottages

Energy Technology Data Exchange (ETDEWEB)

Butler, T. [NAHB Research Center Industry Partnership, Upper Marlboro, MD (United States); Curtis, O. [NAHB Research Center Industry Partnership, Upper Marlboro, MD (United States); Kim, E. [NAHB Research Center Industry Partnership, Upper Marlboro, MD (United States); Roberts, S. [NAHB Research Center Industry Partnership, Upper Marlboro, MD (United States); Stephenson, R. [NAHB Research Center Industry Partnership, Upper Marlboro, MD (United States)

2012-12-01

As part of the NAHB Research Center Industry Partnership, Southface partnered with Martin Dodson Builders and the Serenbe community on the construction of a new test home in the suburbs of Atlanta, GA, in the mixed humid climate zone. The most recent subdivision within the Serenbe community, the Nest, will contain 15 small footprint cottage-style homes, and Southface has selected Lot Nine, as the test home for this study. This Nest subdivision serves as a project showcase for both the builder partner and the Serenbe community as a whole. The planning and design incorporated into the Nest cottages will be implemented in each home within the subdivision. These homes addresses Building America savings targets and serve as a basis of design for other homes Martin Dodson plans to build within the Serenbe community.

Conservation significance of alternative nests of golden eagles

Science.gov (United States)

Brian A. Millsap; Teryl G. Grubb; Robert K. Murphy; Ted Swem; James W. Watson

2015-01-01

Golden eagles (Aquila chrysaetos) are long-lived raptors that maintain nesting territories that may be occupied for a century or longer. Within occupied nesting territories there is one nest in which eagles lay their eggs in a given year (i.e., the used nest), but there are usually other nests (i.e., alternative nests). Conservation plans often protect used nests, but...

Nesting of the Blakiston's Fish-Owl in the Nest of the Steller’s Sea Eagle, Magadan Region, Russia

Directory of Open Access Journals (Sweden)

Irina G. Utekhina

2016-04-01

Full Text Available In 2015 one Steller’s Sea Eagle nest was occupied by a Blakiston’s Fish Owl, the first record of which came from the Nature Reserve Inspector, E.A. Stepanov, who, on May 17, noted the pair of fish owls near a Steller’s Sea Eagle nest on the western bank of the Chelomdja River, 3 km downstream from the Moldot ranger’s station. On that date one of the owls was sitting in the nest, and another was sitting in a tree nearby the nest. On May 26, E. Stepanov observed the owls in the same position. We observed the nest on 20 and 21 June 2015, and saw one large Blakiston’s Fish Owl chick in the nest; no adults were noted. Inspector A. Stepanov saw the chick in the nest on June 23, and an adult in a nearby.  Magadan State Reserve Inspector A. Akhanov reported that the nest was empty and no adults were seen on June 25.

Strong selection on mandible and nest features in a carpenter bee that nests in two sympatric host plants

OpenAIRE

Flores-Prado, Luis; Pinto, Carlos F; Rojas, Alejandra; Fontúrbel, Francisco E

2014-01-01

Host plants are used by herbivorous insects as feeding or nesting resources. In wood-boring insects, host plants features may impose selective forces leading to phenotypic differentiation on traits related to nest construction. Carpenter bees build their nests in dead stems or dry twigs of shrubs and trees; thus, mandibles are essential for the nesting process, and the nest is required for egg laying and offspring survival. We explored the shape and intensity of natural selection on phenotypi...

Factors Affecting Green Residential Building Development: Social Network Analysis

Directory of Open Access Journals (Sweden)

Xiaodong Yang

2018-05-01

Full Text Available Green residential buildings (GRBs are one of the effective practices of energy saving and emission reduction in the construction industry. However, many real estate developers in China are less willing to develop GRBs, because of the factors affecting green residential building development (GRBD. In order to promote the sustainable development of GRBs in China, this paper, based on the perspective of real estate developers, identifies the influential and critical factors affecting GRBD, using the method of social network analysis (SNA. Firstly, 14 factors affecting GRBD are determined from 64 preliminary factors of three main elements, and the framework is established. Secondly, the relationships between the 14 factors are analyzed by SNA. Finally, four critical factors for GRBD, which are on the local economy development level, development strategy and innovation orientation, developer’s acknowledgement and positioning for GRBD, and experience and ability for GRBD, are identified by the social network centrality test. The findings illustrate the key issues that affect the development of GRBs, and provide references for policy making by the government and strategy formulation by real estate developers.

[Nested species subsets of amphibians and reptiles in Thousand Island Lake].

Science.gov (United States)

Wang, Xi; Wang, Yan-Ping; Ding, Ping

2012-10-01

Habitat fragmentation is a main cause for the loss of biological diversity. Combining line-transect methods to survey the amphibians and reptiles on 23 islands on Thousand Island Lake in Zhejiang province, along with survey data on nearby plant species and habitat variables collected by GIS, we used the"BINMATNEST (binary matrix nestedness temperature calculator)" software and the Spearman rank correlation to examine whether amphibians and reptiles followed nested subsets and their influencing factors. The results showed that amphibians and reptiles were significantly nested, and that the island area and habitat type were significantly associated with their nested ranks. Therefore, to effectively protect amphibians and reptiles in the Thousand Islands Lake area we should pay prior attention to islands with larger areas and more habitat types.

Trait-mediated trophic cascade creates enemy-free space for nesting hummingbirds.

Science.gov (United States)

Greeney, Harold F; Meneses, M Rocio; Hamilton, Chris E; Lichter-Marck, Eli; Mannan, R William; Snyder, Noel; Snyder, Helen; Wethington, Susan M; Dyer, Lee A

2015-09-01

The indirect effects of predators on nonadjacent trophic levels, mediated through traits of intervening species, are collectively known as trait-mediated trophic cascades. Although birds are important predators in terrestrial ecosystems, clear examples of trait-mediated indirect effects involving bird predators have almost never been documented. Such indirect effects are important for structuring ecological communities and are likely to be negatively impacted by habitat fragmentation, climate change, and other factors that reduce abundance of top predators. We demonstrate that hummingbirds in Arizona realize increased breeding success when nesting in association with hawks. An enemy-free nesting space is created when jays, an important source of mortality for hummingbird nests, alter their foraging behavior in the presence of their hawk predators.

The role of egg-nest contrast in the rejection of brood parasitic eggs.

Science.gov (United States)

Aidala, Zachary; Croston, Rebecca; Schwartz, Jessica; Tong, Lainga; Hauber, Mark E

2015-04-15

Hosts of avian brood parasites can avoid the reproductive costs of raising genetically unrelated offspring by rejecting parasitic eggs. The perceptual cues and controls mediating parasitic egg discrimination and ejection are well studied: hosts are thought to use differences in egg color, brightness, maculation, size and shape to discriminate between their own and foreign eggs. Most theories of brood parasitism implicitly assume that the primary criteria to which hosts attend when discriminating eggs are differences between the eggs themselves. However, this assumption is confounded by the degree to which chromatic and achromatic characteristics of the nest lining co-vary with egg coloration, so that egg-nest contrast per se might be the recognition cue driving parasitic egg detection. Here, we systematically tested whether and how egg-nest contrast itself contributes to foreign egg discrimination. In an artificial parasitism experiment, we independently manipulated egg color and nest lining color of the egg-ejector American robin (Turdus migratorius), a host of the obligate brood parasitic brown-headed cowbird (Molothrus ater). We hypothesized that the degree of contrast between foreign eggs and the nest background would affect host egg rejection behavior. We predicted that experimentally decreasing egg-nest chromatic and achromatic contrast (i.e. rendering parasitic eggs more cryptic against the nest lining) would decrease rejection rates, while increasing egg-nest contrast would increase rejection rates. In contrast to our predictions, egg-nest contrast was not a significant predictor of egg ejection patterns. Instead, egg color significantly predicted responses to parasitism. We conclude that egg-egg differences are the primary drivers of egg rejection in this system. Future studies should test for the effects of egg-nest contrast per se in predicting parasitic egg recognition in other host-parasite systems, including those hosts building enclosed nests and

Risk factors for tuberculosis among health care workers in South India: a nested case-control study.

Science.gov (United States)

Mathew, Anoop; David, Thambu; Thomas, Kurien; Kuruvilla, P J; Balaji, V; Jesudason, Mary V; Samuel, Prasanna

2013-01-01

The epidemiology of tuberculosis (TB) among health care workers (HCWs) in India remains under-researched. This study is a nested case-control design assessing the risk factors for acquiring TB among HCWs in India. It is a nested case-control study conducted at a tertiary teaching hospital in India. Cases (n = 101) were HCWs with active TB. Controls (n = 101) were HCWs who did not have TB, randomly selected from the 6,003 subjects employed at the facility. Cases and controls were compared with respect to clinical and demographic variables. The cases and controls were of similar age. Logistic regression analysis showed that body mass index (BMI) <19 kg/m(2) (odds ratio [OR]: 2.96, 95% confidence interval [CI]: 1.49-5.87), having frequent contact with patients (OR: 2.83, 95% CI: 1.47-5.45) and being employed in medical wards (OR: 12.37, 95% CI: 1.38-110.17) or microbiology laboratories (OR: 5.65, 95% CI: 1.74-18.36) were independently associated with increased risk of acquiring TB. HCWs with frequent patient contact and those with BMI <19 kg/m(2) were at high risk of acquiring active TB. Nosocomial transmission of TB was pronounced in locations, such as medical wards and microbiology laboratories. Surveillance of high-risk HCWs and appropriate infrastructure modifications may be important to prevent interpersonal TB transmission in health care facilities. Copyright © 2013 Elsevier Inc. All rights reserved.

Factors affecting dignity of patients with multiple sclerosis.

Science.gov (United States)

Sharifi, Simin; Borhani, Fariba; Abbaszadeh, Abbas

2016-12-01

MS is one of the most common chronic diseases of the nervous system. Apart from disease progression, other complications such as unemployment, separation and divorce could potentially threat patients' dignity. Most of the previous studies have been done of maintaining patients' dignity in interaction with healthcare team, but studies on affecting factors of dignity in chronic patients in the society and in interaction with usual people are scarce. We aimed to investigate factors affecting dignity of Iranian patients with MS in daily living and in interaction of them with the society. In this qualitative study, 13 patients with multiple sclerosis were chosen by purposive sampling and semi-structured interviews were conducted until data saturation. The study was done in Tehran, the capital city of Iran. Factors affecting dignity were classified as 'personal factors' and 'social factors'. Personal factors consist of the following subcategories: patients' communication with self, patients' knowledge, patients' values and beliefs and patients' resources. Social factors include others' communication with patients, social knowledge, social values and beliefs and social resources. Multiple personal and social factors interfere in perceived patient dignity. In fact, interaction between personal and social factors can be influential in final perceived dignity. By focusing on whole aspects of the patients' lives, we can identify dignity-promoting or dignity-threatening factors and help patients maintain their dignity by taking appropriate measures for moderating threatening factors and improving dignity enhancing ones. © 2016 Nordic College of Caring Science.

Nest site selection and breeding success in three Turdus thrush species coexisting in an urban environment

Czech Academy of Sciences Publication Activity Database

Mikula, P.; Hromada, M.; Albrecht, Tomáš; Tryjanowski, P.

2014-01-01

Roč. 49, č. 1 (2014), s. 83-92 ISSN 0001-6454 Institutional support: RVO:68081766 Keywords : breeding success * coexistence * nest-habitat partitioning * nest site selection * predation * synurbization * urban habitat * thrushes Subject RIV: EG - Zoology Impact factor: 0.745, year: 2014

Nesting characteristics of mourning doves in central New Mexico: Response to riparian forest change

Science.gov (United States)

D. Max Smith; Deborah M. Finch; David L. Hawksworth

2012-01-01

Riparian forests of the American Southwest are especially prone to changes in composition and structure due to natural and anthropogenic factors. To determine how breeding mourning doves (Zenaida macroura) respond to these changes, we examined nest site use and nest survival in control plots, fuel reduction plots before and after mechanical thinning, and post-wildfire...

Repeatability of nest morphology in African weaver birds.

Science.gov (United States)

Walsh, Patrick T; Hansell, Mike; Borello, Wendy D; Healy, Susan D

2010-04-23

It is generally assumed that birds build nests according to a genetic 'template', little influenced by learning or memory. One way to confirm the role of genetics in nest building is to assess the repeatability of nest morphology with repeated nest attempts. Solitary weaver birds, which build multiple nests in a single breeding season, are a useful group with which to do this. Here we show that repeatability of nest morphology was low, but significant, in male Southern Masked weaver birds and not significant in the Village weavers. The larger bodied Village weavers built larger nests than did Southern Masked weavers, but body size did not explain variation in Southern Masked weaver nest dimensions. Nests built by the same male in both species got shorter and lighter as more nests were constructed. While these data demonstrate the potential for a genetic component of variation in nest building in solitary weavers, it is also clear that there remains plenty of scope in both of these species for experience to shape nest construction.

Nest Construction by a Ground-nesting Bird Represents a Potential Trade-off Between Egg Crypticity and Thermoregulation

Science.gov (United States)

Predation selects against conspicuous colors in bird eggs and nests, while thermoregulatory constraints select for nest building behavior that regulates incubation temperatures. We present results that reveal a trade-off between nest crypticity and thermoregulation of eggs base...

Impact of nest sanitation on the immune system of parents and nestlings in a passerine bird.

Science.gov (United States)

Evans, Jessica K; Griffith, Simon C; Klasing, Kirk C; Buchanan, Katherine L

2016-07-01

Bacterial communities are thought to have fundamental effects on the growth and development of nestling birds. The antigen exposure hypothesis suggests that, for both nestlings and adult birds, exposure to a diverse range of bacteria would select for stronger immune defences. However, there are relatively few studies that have tested the immune/bacterial relationships outside of domestic poultry. We therefore sought to examine indices of immunity (microbial killing ability in naive birds, which is a measure of innate immunity, and the antibody response to sheep red blood cells, which measures adaptive immunity) in both adult and nestling zebra finches (Taeniopygia guttata). We did this throughout breeding and between reproductive attempts in nests that were experimentally manipulated to change the intensity of bacterial exposure. Our results suggest that nest sanitation and bacterial load affected measures of the adaptive immune system, but not the innate immune parameters tested. Adult finches breeding in clean nests had a lower primary antibody response to sheep red blood cells, particularly males, and a greater difference between primary and secondary responses. Adult microbial killing of Escherichia coli decreased as parents moved from incubation to nestling rearing for both nest treatments; however, killing of Candida albicans remained consistent throughout. In nestlings, both innate microbial killing and the adaptive antibody response did not differ between nest environments. Together, these results suggest that exposure to microorganisms in the environment affects the adaptive immune system in nesting birds, with exposure upregulating the antibody response in adult birds. © 2016. Published by The Company of Biologists Ltd.

Sensitivity of Coastal Environments and Wildlife to Spilled Oil: New Hampshire: NESTS (Nest Points)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for nesting birds in New Hampshire. Vector points in this data set represent locations of nesting osprey...

Factor affecting Agrobacterium -mediated transformation of rice ...

African Journals Online (AJOL)

Potato is a very important food crop and is adversely affected by fungus. Agrobacterium-mediated transformation can play an important role in the improvement of potato. The present study was conducted to optimize the different factors affecting Agrobacterium-mediated transformation of chitinase gene. Nodes were used as ...

Endophagy of biting midges attacking cavity-nesting birds

Czech Academy of Sciences Publication Activity Database

Votýpka, Jan; Synek, P.; Svobodová, M.

2009-01-01

Roč. 23, č. 3 (2009), s. 277-280 ISSN 0269-283X R&D Projects: GA MŠk(CZ) LC06009 Institutional research plan: CEZ:AV0Z60220518 Keywords : Culicoides pictipennis * Culicoides truncorum * endophagy * nest box * population dynamics * transmission * vectors * Moravia Subject RIV: EG - Zoology Impact factor: 2.092, year: 2009

Factors affecting patient dose in diagnostic radiology

International Nuclear Information System (INIS)

Poletti, J.L.

1994-03-01

The report, Factors Affecting Patient Dose in Diagnostic Radiology is divided into three main sections. Part one is introductory and covers the basic principles of x-ray production and image formation. It includes discussion of x-ray generators and x-ray tubes, radiation properties and units, specification and measurement of x-ray beams, methods of patient dose measurement, radiation effects, radiation protection philosophy and finally the essentials of imaging systems. Part two examines factors affecting the x-ray output of x-ray machines and the characteristics of x-ray beams. These include the influence of heat ratings, kVp, waveform, exposure timer, filtration, focus-film distance, beam intensity distribution, x-ray tube age and focal spot size. Part three examines x-ray machine, equipment and patient factors which affect the dose received by individual patients. The factors considered include justification of examinations, choice of examination method, film/screen combinations, kVp, mAs, focus-film distance, collimation and field size, exposure time, projection, scatter, generator calibration errors, waveform, filtration, film processing and patient size. The patient dose implications of fluoroscopy systems, CT scanners, special procedures and mammography are also discussed. The report concludes with a brief discussion of patient dose levels in New Zealand and dose optimisation. 104 refs., 32 figs., 27 tabs

Overview of factors affecting the leachability of nuclear waste forms

International Nuclear Information System (INIS)

Stone, J.A.

1980-01-01

An overview of various factors that affect the leachability of nuclear waste forms is presented. The factors affect primarily the leaching system (temperature, for example), the leachant (pH, for example), or the solid being leached (surface condition, for example). A qualitative understanding exists of the major factors affecting leaching, but further studies are needed to establish leaching mechanisms and develop predictive models. 67 refs

Nest trampling and ground nesting birds: Quantifying temporal and spatial overlap between cattle activity and breeding redshank.

Science.gov (United States)

Sharps, Elwyn; Smart, Jennifer; Mason, Lucy R; Jones, Kate; Skov, Martin W; Garbutt, Angus; Hiddink, Jan G

2017-08-01

Conservation grazing for breeding birds needs to balance the positive effects on vegetation structure and negative effects of nest trampling. In the UK, populations of Common redshank Tringa totanus breeding on saltmarshes declined by >50% between 1985 and 2011. These declines have been linked to changes in grazing management. The highest breeding densities of redshank on saltmarshes are found in lightly grazed areas. Conservation initiatives have encouraged low-intensity grazing at nest trampling. If livestock distribution is not spatially or temporally homogenous but concentrated where and when redshank breed, rates of nest trampling may be much higher than expected based on livestock density alone. By GPS tracking cattle on saltmarshes and monitoring trampling of dummy nests, this study quantified (i) the spatial and temporal distribution of cattle in relation to the distribution of redshank nesting habitats and (ii) trampling rates of dummy nests. The distribution of livestock was highly variable depending on both time in the season and the saltmarsh under study, with cattle using between 3% and 42% of the saltmarsh extent and spending most their time on higher elevation habitat within 500 m of the sea wall, but moving further onto the saltmarsh as the season progressed. Breeding redshank also nest on these higher elevation zones, and this breeding coincides with the early period of grazing. Probability of nest trampling was correlated to livestock density and was up to six times higher in the areas where redshank breed. This overlap in both space and time of the habitat use of cattle and redshank means that the trampling probability of a nest can be much higher than would be expected based on standard measures of cattle density. Synthesis and applications : Because saltmarsh grazing is required to maintain a favorable vegetation structure for redshank breeding, grazing management should aim to keep livestock away from redshank nesting habitat between mid

The design and function of birds' nests

Science.gov (United States)

Mainwaring, Mark C; Hartley, Ian R; Lambrechts, Marcel M; Deeming, D Charles

2014-01-01

All birds construct nests in which to lay eggs and/or raise offspring. Traditionally, it was thought that natural selection and the requirement to minimize the risk of predation determined the design of completed nests. However, it is becoming increasingly apparent that sexual selection also influences nest design. This is an important development as while species such as bowerbirds build structures that are extended phenotypic signals whose sole purpose is to attract a mate, nests contain eggs and/or offspring, thereby suggesting a direct trade-off between the conflicting requirements of natural and sexual selection. Nest design also varies adaptively in order to both minimize the detrimental effects of parasites and to create a suitable microclimate for parents and developing offspring in relation to predictable variation in environmental conditions. Our understanding of the design and function of birds' nests has increased considerably in recent years, and the evidence suggests that nests have four nonmutually exclusive functions. Consequently, we conclude that the design of birds' nests is far more sophisticated than previously realized and that nests are multifunctional structures that have important fitness consequences for the builder/s. PMID:25505520

The design and function of birds' nests.

Science.gov (United States)

Mainwaring, Mark C; Hartley, Ian R; Lambrechts, Marcel M; Deeming, D Charles

2014-10-01

All birds construct nests in which to lay eggs and/or raise offspring. Traditionally, it was thought that natural selection and the requirement to minimize the risk of predation determined the design of completed nests. However, it is becoming increasingly apparent that sexual selection also influences nest design. This is an important development as while species such as bowerbirds build structures that are extended phenotypic signals whose sole purpose is to attract a mate, nests contain eggs and/or offspring, thereby suggesting a direct trade-off between the conflicting requirements of natural and sexual selection. Nest design also varies adaptively in order to both minimize the detrimental effects of parasites and to create a suitable microclimate for parents and developing offspring in relation to predictable variation in environmental conditions. Our understanding of the design and function of birds' nests has increased considerably in recent years, and the evidence suggests that nests have four nonmutually exclusive functions. Consequently, we conclude that the design of birds' nests is far more sophisticated than previously realized and that nests are multifunctional structures that have important fitness consequences for the builder/s.

Selection of nest-site habitat by interior least terns in relation to sandbar construction

Science.gov (United States)

Sherfy, Mark H.; Stucker, Jennifer H.; Buhl, Deborah A.

2012-01-01

Federally endangered interior least terns (Sternula antillarum) nest on bare or sparsely vegetated sandbars on midcontinent river systems. Loss of nesting habitat has been implicated as a cause of population declines, and managing these habitats is a major initiative in population recovery. One such initiative involves construction of mid-channel sandbars on the Missouri River, where natural sandbar habitat has declined in quantity and quality since the late 1990s. We evaluated nest-site habitat selection by least terns on constructed and natural sandbars by comparing vegetation, substrate, and debris variables at nest sites (n = 798) and random points (n = 1,113) in bare or sparsely vegetated habitats. Our logistic regression models revealed that a broader suite of habitat features was important in nest-site selection on constructed than on natural sandbars. Odds ratios for habitat variables indicated that avoidance of habitat features was the dominant nest-site selection process on both sandbar types, with nesting terns being attracted to nest-site habitat features (gravel and debris) and avoiding vegetation only on constructed sandbars, and avoiding silt and leaf litter on both sandbar types. Despite the seemingly uniform nature of these habitats, our results suggest that a complex suite of habitat features influences nest-site choice by least terns. However, nest-site selection in this social, colonially nesting species may be influenced by other factors, including spatial arrangement of bare sand habitat, proximity to other least terns, and prior habitat occupancy by piping plovers (Charadrius melodus). We found that nest-site selection was sensitive to subtle variation in habitat features, suggesting that rigor in maintaining habitat condition will be necessary in managing sandbars for the benefit of least terns. Further, management strategies that reduce habitat features that are avoided by least terns may be the most beneficial to nesting least terns.

Estimating raptor nesting success: old and new approaches

Science.gov (United States)

Brown, Jessi L.; Steenhof, Karen; Kochert, Michael N.; Bond, Laura

2013-01-01

Studies of nesting success can be valuable in assessing the status of raptor populations, but differing monitoring protocols can present unique challenges when comparing populations of different species across time or geographic areas. We used large datasets from long-term studies of 3 raptor species to compare estimates of apparent nest success (ANS, the ratio of successful to total number of nesting attempts), Mayfield nesting success, and the logistic-exposure model of nest survival. Golden eagles (Aquila chrysaetos), prairie falcons (Falco mexicanus), and American kestrels (F. sparverius) differ in their breeding biology and the methods often used to monitor their reproduction. Mayfield and logistic-exposure models generated similar estimates of nesting success with similar levels of precision. Apparent nest success overestimated nesting success and was particularly sensitive to inclusion of nesting attempts discovered late in the nesting season. Thus, the ANS estimator is inappropriate when exact point estimates are required, especially when most raptor pairs cannot be located before or soon after laying eggs. However, ANS may be sufficient to assess long-term trends of species in which nesting attempts are highly detectable.

SOCIO-ECONOMIC FACTORS AFFECTING APPLE PRODUCTION ...

African Journals Online (AJOL)

ACSS

Research Organisation scientists working directly with apple farmers ... be productive up to 40 years, it was more realistic to consider .... to determine the factors that affect apple production. ..... profit maximising model using flexible production ...

Hotter nests produce hatchling lizards with lower thermal tolerance.

Science.gov (United States)

Dayananda, Buddhi; Murray, Brad R; Webb, Jonathan K

2017-06-15

In many regions, the frequency and duration of summer heatwaves is predicted to increase in future. Hotter summers could result in higher temperatures inside lizard nests, potentially exposing embryos to thermally stressful conditions during development. Potentially, developmentally plastic shifts in thermal tolerance could allow lizards to adapt to climate warming. To determine how higher nest temperatures affect the thermal tolerance of hatchling geckos, we incubated eggs of the rock-dwelling velvet gecko, Amalosia lesueurii , at two fluctuating temperature regimes to mimic current nest temperatures (mean 23.2°C, range 10-33°C, 'cold') and future nest temperatures (mean 27.0°C, range 14-37°C, 'hot'). Hatchlings from the hot incubation group hatched 27 days earlier and had a lower critical thermal maximum (CT max 38.7°C) and a higher critical thermal minimum (CT min 6.2°C) than hatchlings from cold incubation group (40.2 and 5.7°C, respectively). In the field, hatchlings typically settle under rocks near communal nests. During the hatching period, rock temperatures ranged from 13 to 59°C, and regularly exceeded the CT max of both hot- and cold-incubated hatchlings. Because rock temperatures were so high, the heat tolerance of lizards had little effect on their ability to exploit rocks as retreat sites. Instead, the timing of hatching dictated whether lizards could exploit rocks as retreat sites; that is, cold-incubated lizards that hatched later encountered less thermally stressful environments than earlier hatching hot-incubated lizards. In conclusion, we found no evidence that CT max can shift upwards in response to higher incubation temperatures, suggesting that hotter summers may increase the vulnerability of lizards to climate warming. © 2017. Published by The Company of Biologists Ltd.

Factors Affecting Entrepreneurship and Business Sustainability

Directory of Open Access Journals (Sweden)

Ana Tur-Porcar

2018-02-01

Full Text Available Sustainability is becoming increasingly important for society, and the creation of business ventures is one area where sustainability is critical. We examined the factors affecting actions that are designed to foster business sustainability. These factors are related to the environment, behavior, human relations, and business activity. Based on questionnaire responses from experts, the Analytic Hierarchy Process (AHP method was used to rank sustainable business criteria according to their importance for entrepreneurs starting sustainable businesses. The results indicate that the most important drivers of sustainable entrepreneurship are behavioral factors and business factors. Ethical principles and values, together with competitive intelligence, are crucial for undertaking actions that lead to sustainability.

Nest sanitation through defecation: antifungal properties of wood cockroach feces

Science.gov (United States)

Rosengaus, Rebeca B.; Mead, Kerry; Du Comb, William S.; Benson, Ryan W.; Godoy, Veronica G.

2013-11-01

The wood cockroach Cryptocercus punctulatus nests as family units inside decayed wood, a substrate known for its high microbial load. We tested the hypothesis that defecation within their nests, a common occurrence in this species, reduces the probability of fungal development. Conidia of the entomopathogenic fungus, Metarhizium anisopliae, were incubated with crushed feces and subsequently plated on potato dextrose agar. Relative to controls, the viability of fungal conidia was significantly reduced following incubation with feces and was negatively correlated with incubation time. Although the cockroach's hindgut contained abundant β-1,3-glucanase activity, its feces had no detectable enzymatic function. Hence, these enzymes are unlikely the source of the fungistasis. Instead, the antifungal compound(s) of the feces involved heat-sensitive factor(s) of potential microbial origin. When feces were boiled or when they were subjected to ultraviolet radiation and subsequently incubated with conidia, viability was "rescued" and germination rates were similar to those of controls. Filtration experiments indicate that the fungistatic activity of feces results from chemical interference. Because Cryptocercidae cockroaches have been considered appropriate models to make inferences about the factors fostering the evolution of termite sociality, we suggest that nesting in microbe-rich environments likely selected for the coupling of intranest defecation and feces fungistasis in the common ancestor of wood cockroaches and termites. This might in turn have served as a preadaptation that prevented mycosis as these phylogenetically related taxa diverged and evolved respectively into subsocial and eusocial organizations.

Factors associated with Clostridium difficile infection: A nested case-control study in a three year prospective cohort.

Science.gov (United States)

Khanafer, Nagham; Vanhems, Philippe; Barbut, Frédéric; Luxemburger, Christine

2017-04-01

Clostridium difficile infection (CDI) is a serious medical condition that is associated with substantial morbidity and mortality. Identification of risk factors associated with CDI and prompt recognition of patients at risk is key to successfully preventing CDI. A 3-year prospective, observational, cohort study was conducted in a French university hospital and a nested case-control study was performed to identify risk factors for CDI. Inpatients aged 18 years or older, suffering from diarrhea suspected to be related to CDI, were asked to participate. A total of 945 patients were included, of which 233 cases had a confirmed CDI. CDI infection was more common in men (58.4%) (P = 0.04) compared with patients with diarrhea not related to C. difficile. Previous hospitalization (P infection control issues. In future, these "high-risk" patients may benefit from novel agents being developed to prevent CDI. Copyright © 2017 Elsevier Ltd. All rights reserved.

EFL Students' and Teachers' Attitudes toward Foreign Language Speaking Anxiety: A Look at NESTs and Non-NESTs

Science.gov (United States)

Han, Turgay; Tanriöver, Ahmet Serkan; Sahan, Özgür

2016-01-01

Native English Speaking Teachers (NESTs) have been employed in various English language teaching (ELT) positions and departments at private and state universities in Turkey, particularly over the last three decades. However, undergraduate EFL students' attitudes toward NESTs and Non-Native English Speaking Teachers (Non-NESTs) remain seriously…

Copper accumulation by stickleback nests containing spiggin.

Science.gov (United States)

Pinho, G L L; Martins, C M G; Barber, I

2016-07-01

The three-spined stickleback is a ubiquitous fish of marine, brackish and freshwater ecosystems across the Northern hemisphere that presents intermediate sensitivity to copper. Male sticklebacks display a range of elaborate reproductive behaviours that include nest construction. To build the nests, each male binds nesting material together using an endogenous glycoprotein nesting glue, known as 'spiggin'. Spiggin is a cysteine-rich protein and, therefore, potentially binds heavy metals present in the environment. The aim of this study was to investigate the capacity of stickleback nests to accumulate copper from environmental sources. Newly built nests, constructed by male fish from polyester threads in laboratory aquaria, were immersed in copper solutions ranging in concentration from 21.1-626.6 μg Cu L(-1). Bundles of polyester threads from aquaria without male fish were also immersed in the same copper solutions. After immersion, nests presented higher amounts of copper than the thread bundles, indicating a higher capacity of nests to bind this metal. A significant, positive correlation between the concentration of copper in the exposure solution and in the exposed nests was identified, but there was no such relationship for thread bundles. Since both spiggin synthesis and male courtship behaviour are under the control of circulating androgens, we predicted that males with high courtship scores would produce and secrete high levels of the spiggin protein. In the present study, nests built by high courtship score males accumulated more copper than those built by low courtship score males. Considering the potential of spiggin to bind metals, the positive relationship between fish courtship and spiggin secretion seems to explain the higher amount of copper on the nests from the fish showing high behaviour scores. Further work is now needed to determine the consequences of the copper binding potential of spiggin in stickleback nests for the health and survival of

Factors Affecting the Productivity of Government Workers

Directory of Open Access Journals (Sweden)

Jerry P. Haenisch

2012-01-01

Full Text Available While there have been a variety of studies concerning government worker motivation and productivity, few, if any, studies have focused specifically on state government workers’ perceptions about what factors affect their productivity. With more than 5 million workers employed by state governments in the United States, any improvement in state workplace productivity could have significant financial and service impact for society. In this study, state government workers identified those factors perceived as most affecting their workplace productivity. Data were collected through a survey offered to state government workers in the state of Wyoming. Factor analysis was used to derive key productivity factors from survey responses. The results indicate that state government workers appreciate having freedom and autonomy, like their jobs and the sense of achievement, and welcome teamwork, but feel limited by poor supervision and management, poor communications, and insufficient budgets and staffing. To improve productivity, the workers would eliminate bureaucracy, supervise better, and improve communication.

The effect of water on the ground nesting habits of the giant tropical ant, Paraponera clavata.

Science.gov (United States)

Elahi, Robin

2005-11-18

The large predatory ant, Paraponera clavata, exerts measurable top-down effects in wet and moist Neotropical forests, and therefore its distribution has potential ecological implications. To determine how water affects the presence of this important predator, the ground nesting ecology of P. clavata was examined with respect to various habitat characteristics. Four hectares of disturbed Costa Rican lowland rain forest were surveyed for ant colonies to determine nest distribution patterns in wet and dry habitat; significantly more colonies were found in dry habitat. Seventeen of 19 nests built on slopes of > 5 degrees inclination were positioned on the downward side of the tree, possibly using the trunk as a shield against runoff during rain showers. Moisture and pH inside nests were significantly different from adjacent soil. These results suggest that water influences the ground nesting habits of P. clavata, thus ecological differences between comparatively wet and dry portions of tropical forests may arise from the relative abundance of this ant species.

Construction patterns of birds' nests provide insight into nest-building behaviours

OpenAIRE

Biddle, Lucia; Goodman, Adrian; Deeming, Charles

2017-01-01

Previous studies have suggested that birds and mammals select materials needed for nest building based on their thermal or structural properties, although the amounts or properties of the materials used have been recorded for only a very small number of species. Some of the behaviours underlying the construction of nests can be indirectly determined by careful deconstruction of the structure and measurement of the biomechanical properties of the materials used. Here we examined this idea in a...

Nest-building behavior of Monk Parakeets and insights into potential mechanisms for reducing damage to utility poles

Directory of Open Access Journals (Sweden)

Kevin R. Burgio

2014-09-01

Full Text Available The Monk Parakeet (Myiopsitta monachus commonly uses utility poles as a substrate for building large, bulky nests. These nests often cause fires and electric power outages, creating public safety risks and increasing liability and maintenance costs for electric companies. Previous research has focused on lethal methods and chemical contraception to prevent nesting on utility poles and electrical substations. However, implementation of lethal methods has led to public protests and lawsuits, while chemical contraception may affect other than the targeted species, and must be continually reapplied for effectiveness. One non-lethal alternative, nest removal, is costly and may not be a sustainable measure if Monk Parakeet populations continue to grow. In order to identify cost-effective non-lethal solutions to problems caused by Monk Parakeet nesting, we studied their behavior as they built nests on utility poles. Monk Parakeets initiate nests by attaching sticks at the intersection of the pole and electric lines. We found that parakeets use the electric lines exclusively to gain access to the intersection of lines and pole during nest initiation, and continue to use the lines intensively throughout construction. Monk Parakeets also have more difficulty attaching sticks during the early stages of nest construction than when the nest is nearing completion. These findings suggest that intervention during the earlier stages of nest building, by excluding Monk Parakeets from electric lines adjacent to poles, may be an effective, non-lethal method of reducing or eliminating parakeets nesting on, and damaging, utility poles.

Constructing bald eagle nests with natural materials

Science.gov (United States)

T. G. Grubb

1995-01-01

A technique for using natural materials to build artificial nests for bald eagles (Haliaeetus leucocephalus) and other raptors is detailed. Properly constructed nests are as permanently secured to the nest tree or cliff substrate as any eagle-built nest or human-made platform. Construction normally requires about three hours and at least two people. This technique is...

Bristol Bay, Alaska Subarea ESI: NESTS (Nest Points)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for nesting seabirds (alcids, pelagic birds), gulls, terns, diving birds, and raptors in the Bristol Bay...

Evaluating nest supplementation as a recovery strategy for the endangered rodents of the Florida Keys

Science.gov (United States)

Cove, Michael V.; Simons, Theodore R.; Gardner, Beth; Maurer, Andrew S.; O'Connell, Allan F.

2017-01-01

The Key Largo woodrat (Neotoma floridana smalli) and Key Largo cotton mouse (Peromyscus gossypinus allapaticola) are federally endangered subspecies endemic to the tropical hardwood hammocks of Key Largo, Florida. Woodrats are considered generalists in habitat and diet, yet a steady decline in natural stick nests and capture rates over the past several decades suggests that they are limited by the availability of nesting habitat due to habitat loss and fragmentation. The more specialized Key Largo cotton mouse appears to rely on old growth hammock, a habitat type that is rare following past land clearing. In 2004, the U.S. Fish and Wildlife Service started building supplemental nest structures to restore habitat quality and connectivity for these endangered rodents, but nest use requires evaluation. We used camera traps and occupancy models to evaluate the factors influencing woodrat and cotton mouse use of the supplemental nests. We detected woodrats at 65 and cotton mice at 175 of 284 sampled nest structures, with co-occurrence at 38 nests. Woodrat nest use followed a gradient from low nest use in the north to high nest use in the south, which might relate to the proximity of free-ranging domestic cat (Felis catus) colonies in residential developments. Cotton mouse nest use, however, was related positively to mature hammock and related negatively to disturbed areas (e.g. scarified lands). The two species occurred independently of each other. Stick-stacking behavior was observed at supplemental nests and, although it was correlated with detection of woodrats, it was not a strong predictor of their occurrence. We suggest that nest supplementation can be an important tool for species recovery as habitat quality continues to improve with succession.

Mitigation effectiveness for improving nesting success of greater sage-grouse influenced by energy development

Science.gov (United States)

Kirol, Christopher P.; Sutphin, Andrew L.; Bond, Laura S.; Fuller, Mark R.; Maechtle, Thomas L.

2015-01-01

Sagebrush Artemisia spp. habitats being developed for oil and gas reserves are inhabited by sagebrush obligate species — including the greater sage-grouse Centrocercus urophasianus (sage-grouse) that is currently being considered for protection under the U.S. Endangered Species Act. Numerous studies suggest increasing oil and gas development may exacerbate species extinction risks. Therefore, there is a great need for effective on-site mitigation to reduce impacts to co-occurring wildlife such as sage-grouse. Nesting success is a primary factor in avian productivity and declines in nesting success are also thought to be an important contributor to population declines in sage-grouse. From 2008 to 2011 we monitored 296 nests of radio-marked female sage-grouse in a natural gas (NG) field in the Powder River Basin, Wyoming, USA, and compared nest survival in mitigated and non-mitigated development areas and relatively unaltered areas to determine if specific mitigation practices were enhancing nest survival. Nest survival was highest in relatively unaltered habitats followed by mitigated, and then non-mitigated NG areas. Reservoirs used for holding NG discharge water had the greatest support as having a direct relationship to nest survival. Within a 5-km2 area surrounding a nest, the probability of nest failure increased by about 15% for every 1.5 km increase in reservoir water edge. Reducing reservoirs was a mitigation focus and sage-grouse nesting in mitigated areas were exposed to almost half of the amount of water edge compared to those in non-mitigated areas. Further, we found that an increase in sagebrush cover was positively related to nest survival. Consequently, mitigation efforts focused on reducing reservoir construction and reducing surface disturbance, especially when the surface disturbance results in sagebrush removal, are important to enhancing sage-grouse nesting success.

Workers' Extra-Nest Behavioral Changes During Colony Fission in Dinoponera quadriceps (Santschi).

Science.gov (United States)

Medeiros, J; Araújo, A

2014-04-01

Ant colonies can reproduce by two strategies: independent foundation, wherein the queen starts a new colony alone, and dependent foundation, in which workers assist the queen. In the queenless species Dinoponera quadriceps (Santschi), the colony reproduces obligatorily by fission, a type of dependent foundation, but this process is not well understood. This study describes a colony fission event of D. quadriceps in the field and analyzes the influence of the fission process on workers' extra-nest behavior. Based on observations of workers outside the nest, five distinct stages were identified: monodomic stage, polydomic stage, split stage, conflict stage, and post-conflict stage. The colony was initially monodomic and then occupied a second nest before it split into two independent colonies, indicating a gradual and opportunistic dependent foundation. After the fission event, the daughter colony had aggressive conflicts with the parental colony, resulting in the latter's disappearance. Colony fission affected workers' extra-nest behavior by increasing the frequency of rubbing the gaster against the substrate (which probably has a chemical marking function) and by decreasing the frequency of foraging during the split stage. After the fission event, the number of foragers was halved and foragers remained nearer to the nest during extra-nest activity. The spatial closeness of the parental and daughter colonies led to competition that caused the extinction or migration of the parental colony. Intraspecific competition was indicated by foraging directionality at the colony level, whereby areas of neighbor colonies were avoided; this directionality was stronger while both colonies coexisted.

Strong selection on mandible and nest features in a carpenter bee that nests in two sympatric host plants.

Science.gov (United States)

Flores-Prado, Luis; Pinto, Carlos F; Rojas, Alejandra; Fontúrbel, Francisco E

2014-05-01

Host plants are used by herbivorous insects as feeding or nesting resources. In wood-boring insects, host plants features may impose selective forces leading to phenotypic differentiation on traits related to nest construction. Carpenter bees build their nests in dead stems or dry twigs of shrubs and trees; thus, mandibles are essential for the nesting process, and the nest is required for egg laying and offspring survival. We explored the shape and intensity of natural selection on phenotypic variation on three size measures of the bees (intertegular width, wing length, and mandible area) and two nest architecture measures (tunnel length and diameter) on bees using the native species Chusquea quila (Poaceae), and the alloctonous species Rubus ulmifolius (Rosaceae), in central Chile. Our results showed significant and positive linear selection gradients for tunnel length on both hosts, indicating that bees building long nests have more offspring. Bees with broader mandibles show greater fitness on C. quila but not on R. ulmifolius. Considering that C. quila represents a selective force on mandible area, we hypothesized a high adaptive value of this trait, resulting in higher fitness values when nesting on this host, despite its wood is denser and hence more difficult to be bored.

Preference of rabbit does among different nest materials

Directory of Open Access Journals (Sweden)

T.P. Farkas

2018-03-01

Full Text Available Nest quality is important for the survival of new-born rabbits. Nesting material in rabbit farms generally consists of wood shavings, which is completely different from the dry grass used by the European wild rabbit (Oryctolagus cuniculus. The aim of the experiments was to examine which nest materials are preferred by rabbit does when building their nest. In experiment 1, the choice of multiparous rabbit does (n=37 among nest boxes bedded with different nesting materials was monitored. In each pen (1.0×1.83 m 1 doe and 4 nest boxes (0.37×0.23×0.31 m with different nest materials (meadow hay [H], wheat straw [S], fine fibre material [Lignocel®, L] or wood shavings [W] were placed 3 days before the expected parturition (gestation length is about 31 d in the Pannon White breed. Some 48.6% of the does kindled in nest boxes that contained pure materials (L: 40.5%, S: 5.4%, H: 2.7%, and 51.3% of the does kindled in nest boxes where the nest materials of different nest boxes were mixed by the does (S with L: 21.5%, S with L and H: 5.4%, W with L: 8.1%, L with H and S: 5.4%. Does preferred kindling in the nest box bedded with L, and most of them refused the nest box with W. In experiment 2/a (n=32 does and 2/b (n=25 does, each pen (1×0.91 m was equipped with 3 and 2 hay racks and filled with H, S or L, and H or S, respectively. The experiments lasted from the 27th day of pregnancy until the day of parturition and 24-h video recordings (10 does/experiment were evaluated throughout the experiment. The events of carrying the nest materials from the hay racks were registered. In experiment 2/a, the frequency of nest material carrying was highest on the day of parturition. The preferred nest material was L (compared to H and S on each experimental day except day 30 of pregnancy. At the day of kindling, 87.5, 6.3 and 6.3% of the nests contained pure L, mixed L-H and L-S, respectively. In experiment 2/b, the frequency of nest material carrying (mostly S

Review: Factors affecting fouling in conventional pens for slaughter pigs

DEFF Research Database (Denmark)

Larsen, Mona Lilian Vestbjerg; Bertelsen, Maja; Pedersen, Lene Juul

2018-01-01

and pigs’ earlier experience. Further, these primary factors are affected by secondary factors such as the shape of the pen, the weight of the pigs and especially the heat balance of the pigs, which is affected by several tertiary factors including, for example, temperature, humidity and draught. Results...

Effects of wind energy development on nesting ecology of greater prairie-chickens in fragmented grasslands.

Science.gov (United States)

McNew, Lance B; Hunt, Lyla M; Gregory, Andrew J; Wisely, Samantha M; Sandercock, Brett K

2014-08-01

Wind energy is targeted to meet 20% of U.S. energy needs by 2030, but new sites for development of renewable energy may overlap with important habitats of declining populations of grassland birds. Greater Prairie-Chickens (Tympanuchus cupido) are an obligate grassland bird species predicted to respond negatively to energy development. We used a modified before-after control-impact design to test for impacts of a wind energy development on the reproductive ecology of prairie-chickens in a 5-year study. We located 59 and 185 nests before and after development, respectively, of a 201 MW wind energy facility in Greater Prairie-Chicken nesting habitat and assessed nest site selection and nest survival relative to proximity to wind energy infrastructure and habitat conditions. Proximity to turbines did not negatively affect nest site selection (β = 0.03, 95% CI = -1.2-1.3) or nest survival (β = -0.3, 95% CI = -0.6-0.1). Instead, nest site selection and survival were strongly related to vegetative cover and other local conditions determined by management for cattle production. Integration of our project results with previous reports of behavioral avoidance of oil and gas facilities by other species of prairie grouse suggests new avenues for research to mitigate impacts of energy development. © 2014 The Authors. Conservation Biology published by Wiley Periodicals, Inc. on behalf of Society for Conservation Biology.

Factors Affecting Prenatal Care Utilization in East Wollega Zone ...

African Journals Online (AJOL)

The objective of the study was to identify factors affecting utilization of prenatal care and skilled birth attendant in East Wollega zone. Prenatal care and skilled birth attendant are crucial factor which affects the health and wellbeing of the mother and newborn and help the women to access skilled assistance, drugs, ...

The quantum walk search algorithm: Factors affecting efficiency

OpenAIRE

Lovett, Neil B.; Everitt, Matthew; Heath, Robert M.; Kendon, Viv

2011-01-01

We numerically study the quantum walk search algorithm of Shenvi, Kempe and Whaley [PRA \\textbf{67} 052307] and the factors which affect its efficiency in finding an individual state from an unsorted set. Previous work has focused purely on the effects of the dimensionality of the dataset to be searched. Here, we consider the effects of interpolating between dimensions, connectivity of the dataset, and the possibility of disorder in the underlying substrate: all these factors affect the effic...

Determining the Factors Affecting Labor Productivity of Nurses

OpenAIRE

Yurdanur Dikmen; Dilek Kara Yilmaz; Handenur Basaran; Nasibe Yagmur Filiz

2016-01-01

Aim: This study was conducted to determine the factors affecting the labor productivity of nurses. Material and Methods: The study which was planned as descriptive and analytical was carried out with 156 nurses who volunteered to participate in the study in a public hospital in the northwest of Turkey. Data was collected with the and ldquo;Participant Presentation Form and rdquo; and the questionnaire including the factors affecting labor productivity which was developed by Ozkoc (2005). ...

Low heritability of nest construction in a wild bird.

Science.gov (United States)

Järvinen, Pauliina; Kluen, Edward; Brommer, Jon E

2017-10-01

In birds and other taxa, nest construction varies considerably between and within populations. Such variation is hypothesized to have an adaptive (i.e. genetic) basis, but estimates of heritability in nest construction are largely lacking. Here, we demonstrate with data collected over 10 years from 1010 nests built by blue tits in nest-boxes that nest size (height of nest material) and nest composition (proportion of feathers in the nest) are repeatable but only weakly (12-13%) heritable female traits. These findings imply that nest construction may evolve but only if subjected to strong and consistent selection pressures. © 2017 The Author(s).

Eczema in early childhood, sociodemographic factors and lifestyle habits are associated with food allergy: a nested case-control study.

Science.gov (United States)

Ben-Shoshan, Moshe; Soller, Lianne; Harrington, Daniel W; Knoll, Megan; La Vieille, Sebastian; Fragapane, Joseph; Joseph, Lawrence; St Pierre, Yvan; Wilson, Kathie; Elliott, Susan J; Clarke, Ann E

2015-01-01

Studies suggest an increase in food allergy prevalence over the last decade, but the contributing factors remain unknown. The aim of this study was to evaluate the association between the most common food allergies and atopic history, sociodemographic characteristics and lifestyle habits. We conducted a case-control study nested within the SPAACE study (Surveying Prevalence of Food Allergy in All Canadian Environments) – a cross-Canada, random telephone survey. Cases consisted of individuals with probable food allergy (self-report of convincing symptoms and/or physician diagnosis) to milk, egg, peanut, tree nut, shellfish, fish, wheat, soy, or sesame. Controls consisted of nonallergic individuals, matched for age. Cases and controls were queried on personal and family history of atopy, sociodemographic characteristics and lifestyle habits. Multivariate logistic regression was used to evaluate the association between atopy, sociodemographic characteristics and lifestyle habits with probable food allergy. Between September 2010 and September 2011, 480 cases and 4,950 controls completed the questionnaire. For all 9 allergens, factors associated with a higher risk of probable allergy were as follows: (1) personal history of eczema (in the first 2 years of life), asthma or hay fever (odds ratio, OR 2.3, 95% CI 1.6-3.5; OR 2.8, 95% CI 2.2-3.6, and OR 2.3, 95% CI 1.8-3.0, respectively), (2) maternal, paternal or sibling's food allergy (OR 3.7, 95% CI 2.5-5.6; OR 3.0, 95% CI 1.8-5.1, and OR 3.1, 95% CI 2.2-4.2), (3) high household income (top 20%; OR 1.5, 95% CI 1.2-2.0). Males and older individuals were less likely to have food allergy (OR 0.7, 95% CI 0.6-0.9, and OR 0.99, 95% CI 0.99-1.00). Eczema in the first 2 years of life was the strongest risk factor for egg, peanut, tree nut and fish allergy. This is the largest population-based nested case-control study exploring factors associated with food allergies. Our results reveal that, in addition to previously reported

Identifying factors affecting optimal management of agricultural water

Directory of Open Access Journals (Sweden)

Masoud Samian

2015-01-01

In addition to quantitative methodology such as descriptive statistics and factor analysis a qualitative methodology was employed for dynamic simulation among variables through Vensim software. In this study, the factor analysis technique was used through the Kaiser-Meyer-Olkin (KMO and Bartlett tests. From the results, four key elements were identified as factors affecting the optimal management of agricultural water in Hamedan area. These factors were institutional and legal factors, technical and knowledge factors, economic factors and social factors.

Demography, breeding success and effects of nest type in artificial colonies of Red-footed Falcons and allies

Directory of Open Access Journals (Sweden)

Kotymán László

2015-06-01

Full Text Available Shortage of breeding sites is an important limiting factor of bird populations. Artificial breeding platforms, nest-boxes or man-made twig nests often present solutions with remarkable results, however long-term sustainability of these populations remains to be resolved. Furthermore, the question whether the inference of results of studies conducted on birds breeding in artificial breeding sites can be generalized to other populations, still remains open. Here we present the history, and the results of a 20 year old (1995-2015 nest-box programme initiated to increase potential breeding possibilities of Red-footed Falcons in an area, where nest-site shortage was a severe limiting factor. We show how various other species (Jackdaws, Kestrels and Long-eared Owls have utilized these resources, and present descriptive statistics on their reproductive performance. Analysing the data of a total of 1432 breeding attempts, we show that Red-footed Falcons have similar clutch sizes, and nesting success (i.e. ratio of nests with at least on fledgling, however fledging success (ratio of the number of eggs/fledged nestlings was different in artificial nest-boxes. When we excluded closed box types from artificial nests, this difference was not apparent. In case of Kestrels (n=1626 breeding attempts clutch size was significantly higher in artificial nests, while we found no difference in fledging or nesting success. When only comparing open boxes to natural nests, the difference in clutch size was no longer significant. We also analysed the effect of nest box design on reproductive parameters of the two species using regression trees. Inter annual effects were the most important in shaping clutch size and fledging rate of both falcon species, however we also found nest-box design effects, but only in Red-footed Falcons. In years when mean clutch size was high, these birds had lower clutch size in an older, darker nest-box type compared to an alternative design

Factors affecting the runoff response of watersheds to precipitation

OpenAIRE

DROZDOVÁ, Martina

2013-01-01

This bachelor thesis is focused on the factors that affect the drainage basin of the response. It contains a literature review, which deals with the hydrological cycle characteristics of precipitation, surface runoff and flood and erosion protection. The aim of the work is to evaluate the factors that adversely affect the runoff from the catchment.

Demographic consequences of nest box use for Red-footed Falcons Falco vespertinus in Central Asia

Science.gov (United States)

Bragin, Evgeny A.; Bragin, Alexander E.; Katzner, Todd

2017-01-01

Nest box programs are frequently implemented for the conservation of cavity-nesting birds, but their effectiveness is rarely evaluated in comparison to birds not using nest boxes. In the European Palearctic, Red-footed Falcon Falco vespertinus populations are both of high conservation concern and are strongly associated with nest box programs in heavily managed landscapes. We used a 21-year monitoring dataset collected on 753 nesting attempts by Red-footed Falcons in unmanaged natural or semi-natural habitats to provide basic information on this poorly known species; to evaluate long-term demographic trends; and to evaluate response of demographic parameters of Red-footed Falcons to environmental factors including use of nest boxes. We observed significant differences among years in laying date, offspring loss, and numbers of fledglings produced, but not in egg production. Of these four parameters, offspring loss and, to a lesser extent, number of fledglings exhibited directional trends over time. Variation in laying date and in numbers of eggs were not well explained by any one model, but instead by combinations of models, each with informative terms for nest type. Nevertheless, laying in nest boxes occurred 2.10 ± 0.70 days earlier than in natural nests. In contrast, variation in both offspring loss and numbers of fledglings produced were fairly well explained by a single model including terms for nest type, nest location, and an interaction between the two parameters (65% and 81% model weights respectively), with highest offspring loss in nest boxes on forest edges. Because, for other species, earlier laying dates are associated with more fit individuals, this interaction highlighted a possible ecological trap, whereby birds using nest boxes on forest edges lay eggs earlier but suffer greater offspring loss and produce lower numbers of fledglings than do those in other nesting settings. If nest boxes increase offspring loss for Red-footed Falcons in heavily

Economic and Cultural Factors Affecting University Excellence

Science.gov (United States)

Jabnoun, Naceur

2009-01-01

Purpose: The ranking of top universities in the world has generated increased interest in the factors that enhance university performance. The purpose of this paper is to identify economic and cultural factors that affect the number of top ranking universities in each country. Design/methodology/approach: This paper first identifies the number of…

Hierarchically nested river landform sequences

Science.gov (United States)

Pasternack, G. B.; Weber, M. D.; Brown, R. A.; Baig, D.

2017-12-01

River corridors exhibit landforms nested within landforms repeatedly down spatial scales. In this study we developed, tested, and implemented a new way to create river classifications by mapping domains of fluvial processes with respect to the hierarchical organization of topographic complexity that drives fluvial dynamism. We tested this approach on flow convergence routing, a morphodynamic mechanism with different states depending on the structure of nondimensional topographic variability. Five nondimensional landform types with unique functionality (nozzle, wide bar, normal channel, constricted pool, and oversized) represent this process at any flow. When this typology is nested at base flow, bankfull, and floodprone scales it creates a system with up to 125 functional types. This shows how a single mechanism produces complex dynamism via nesting. Given the classification, we answered nine specific scientific questions to investigate the abundance, sequencing, and hierarchical nesting of these new landform types using a 35-km gravel/cobble river segment of the Yuba River in California. The nested structure of flow convergence routing landforms found in this study revealed that bankfull landforms are nested within specific floodprone valley landform types, and these types control bankfull morphodynamics during moderate to large floods. As a result, this study calls into question the prevailing theory that the bankfull channel of a gravel/cobble river is controlled by in-channel, bankfull, and/or small flood flows. Such flows are too small to initiate widespread sediment transport in a gravel/cobble river with topographic complexity.

Factors affecting the organization and management of emergency ...

African Journals Online (AJOL)

Factors affecting the organization and management of emergency mass casualty ... service all under a unified command of leadership with a specified job description. Factors identified were: Political will, human resource planning, appropriate ...

An economical wireless cavity-nest viewer

Science.gov (United States)

Daniel P. Huebner; Sarah R. Hurteau

2007-01-01

Inspection of cavity nests and nest boxes is often required during studies of cavity-nesting birds, and fiberscopes and pole-mounted video cameras are sometimes used for such inspection. However, the cost of these systems may be prohibitive for some potential users. We describe a user-built, wireless cavity viewer that can be used to access cavities as high as 15 m and...

Nesting Biology and Occurrence of Social Nests in a Bivoltine and Basically Solitary Halictine Bee, Lasioglossum (Lasioglossum) scitulum Smith (Hymenoptera : Halictidae)

OpenAIRE

Ryoichi, MIYANAGA; Yasuo, MAETA; Kazuo, HOSHIKAWA; Division of Environmental Biology, Faculty of Life and Environmental Science, Shimane University; Division of Environmental Biology, Faculty of Life and Environmental Science, Shimane University; Division of Environmental Biology, Faculty of Life and Environmental Science, Shimane University

2000-01-01

The life cycle and sociality of the halictine bee, Lasioglossum (Lasioglossum) scitulum were studied in a greenhouse at Matsue (lat. 35°22′N), south-western Japan in 1988 and 1989. This species was a bivoltine bee with solitary to primitively social behavior. During the summer brooding period of 1988, 51 solitary nests and 8 multi-female nests (3 matrifilial and 5 sororal nests) were discovered. In 1989, 11 multi-female nests (3 matrifilial and 8 sororal nests), together with 59 solitary nest...

Factors affecting the duration of nestling period and fledging order in Tengmalm's owl (Aegolius funereus: effect of wing length and hatching sequence.

Directory of Open Access Journals (Sweden)

Marek Kouba

Full Text Available In altricial birds, the nestling period is an important part of the breeding phase because the juveniles may spend quite a long time in the nest, with associated high energy costs for the parents. The length of the nestling period can be variable and its duration may be influenced by both biotic and abiotic factors; however, studies of this have mostly been undertaken on passerine birds. We studied individual duration of nestling period of 98 Tengmalm's owl chicks (Aegolius funereus at 27 nests during five breeding seasons using a camera and chip system and radio-telemetry. We found the nestlings stayed in the nest box for 27 - 38 days from hatching (mean ± SD, 32.4 ± 2.2 days. The individual duration of nestling period was negatively related to wing length, but no formally significant effect was found for body weight, sex, prey availability and/or weather conditions. The fledging sequence of individual nestlings was primarily related to hatching order; no relationship with wing length and/or other factors was found in this case. We suggest the length of wing is the most important measure of body condition and individual quality in Tengmalm's owl young determining the duration of the nestling period. Other differences from passerines (e.g., the lack of effect of weather or prey availability on nestling period are considered likely to be due to different life-history traits, in particular different food habits and nesting sites and greater risk of nest predation among passerines.

Use of a nesting platform by Gull-billed Terns and Black Skimmers at the Salton Sea, California

Science.gov (United States)

Molina, Kathy C.; Ricca, Mark A.; Miles, A. Keith; Schoneman, Christian

2009-01-01

In 2006, we constructed an elevated nesting platform at the Salton Sea, California, and monitored its use by Gull-billed Terns and Black Skimmers over three subsequent breeding seasons. Black Skimmers were the first to colonize the platform with a total of five nests in 2006. In 2007 Gull-billed Terns colonized the platform with a total of 28 nests and the number of Black Skimmer nests increased to 20. Neither species nested on the platform in 2008. Low success for both species was probably influenced by at least two factors. First, when both species nested on the platform, nest densities were higher than is typical of their colonies on larger, earthen islands, and colony success may have been reduced by overcrowding. Second, lack of access to water may have reduced chicks' ability to thermoregulate effectively in the hot environment of the Salton Sea. Refinements to the size, design, and location of artificial nesting habitats are necessary to enhance productivity of colonial groundnesting birds at the Salton Sea successfully.

Observations of indirect filial cannibalism in response to nest failure of Black-crowned Night-Herons (Nycticorax nycticorax)

Science.gov (United States)

Brussee, Brianne E.; Coates, Peter S.; Dwight, Ian; Young, Laura G.

2017-01-01

During 2011, four separate instances of indirect filial cannibalism, whereby adults consumed their young that died from unknown causes, were observed using video-monitoring techniques in a nesting colony of Black-crowned Night-Herons (Nycticorax nycticorax) on Alcatraz Island. Though they were not observed actively killing their young, in all four observations adult Black-crowned Night-Herons consumed their young following death (i.e., indirect filial cannibalism). We could not determine cause of chick mortality, but parental neglect was likely a contributing factor in at least two instances. Indirect filial cannibalism is not commonly documented among birds, and understanding how cannibalism contributes to nest failure can help researchers better understand factors that limit nesting populations.

Translocation of threatened New Zealand falcons to vineyards increases nest attendance, brooding and feeding rates.

Directory of Open Access Journals (Sweden)

Sara M Kross

Full Text Available Anthropogenic landscapes can be rich in resources, and may in some cases provide potential habitat for species whose natural habitat has declined. We used remote videography to assess whether reintroducing individuals of the threatened New Zealand falcon Falco novaeseelandiae into a highly modified agricultural habitat affected the feeding rates of breeding falcons or related breeding behavior such as nest attendance and brooding rates. Over 2,800 recording hours of footage were used to compare the behavior of falcons living in six natural nests (in unmanaged, hilly terrain between 4 km and 20 km from the nearest vineyard, with that of four breeding falcon pairs that had been transported into vineyards and nested within 500 m of the nearest vineyard. Falcons in vineyard nests had higher feeding rates, higher nest attendance, and higher brooding rates. As chick age increased, parents in vineyard nests fed chicks a greater amount of total prey and larger prey items on average than did parents in hill nests. Parents with larger broods brought in larger prey items and a greater total sum of prey biomass. Nevertheless, chicks in nests containing siblings received less daily biomass per individual than single chicks. Some of these results can be attributed to the supplementary feeding of falcons in vineyards. However, even after removing supplementary food from our analysis, falcons in vineyards still fed larger prey items to chicks than did parents in hill nests, suggesting that the anthropogenic habitat may be a viable source of quality food. Although agricultural regions globally are rarely associated with raptor conservation, these results suggest that translocating New Zealand falcons into vineyards has potential for the conservation of this species.

The effect of water on the ground nesting habits of the giant tropical ant, Paraponera clavata

OpenAIRE

Elahi, Robin

2005-01-01

The large predatory ant, Paraponera clavata, exerts measurable top-down effects in wet and moist Neotropical forests, and therefore its distribution has potential ecological implications. To determine how water affects the presence of this important predator, the ground nesting ecology of P. clavata was examined with respect to various habitat characteristics. Four hectares of disturbed Costa Rican lowland rain forest were surveyed for ant colonies to determine nest distribution patterns in w...

Factors affecting the design of instrument flight procedures

Directory of Open Access Journals (Sweden)

Ivan FERENCZ

2008-01-01

Full Text Available The article highlights factors, which might affect the design of instrument flight procedures. Ishikawa diagram is used to distribute individual factors into classes, as are People, Methods, Regulations, Tools, Data and Environment.

Factors Affecting Rural Facilitators’ Role: Iran

OpenAIRE

Azimi, Farideh; Kamali, Mohammad Bagher

2011-01-01

This study aimed to examine key factors affecting rural female facilitators’ role in participatory rural development in Tehran Province. Since the researchers intended to have a better insight into the facilitators’ role and employ inquiry as a learning forum for bringing about changes for all participants, they preferred to use a case study based upon an appreciative inquiry method. The study divided the factors affecting the facilitators’ role into two main categories: driving factors...

Psychological factors affecting equine performance

Directory of Open Access Journals (Sweden)

McBride Sebastian D

2012-09-01

Full Text Available Abstract For optimal individual performance within any equestrian discipline horses must be in peak physical condition and have the correct psychological state. This review discusses the psychological factors that affect the performance of the horse and, in turn, identifies areas within the competition horse industry where current behavioral research and established behavioral modification techniques could be applied to further enhance the performance of animals. In particular, the role of affective processes underpinning temperament, mood and emotional reaction in determining discipline-specific performance is discussed. A comparison is then made between the training and the competition environment and the review completes with a discussion on how behavioral modification techniques and general husbandry can be used advantageously from a performance perspective.

Predation of artificial ground nests on white-tailed prairie dog colonies

Science.gov (United States)

Baker, B.W.; Stanley, T.R.; Sedgwick, J.A.

1999-01-01

Prairie dog (Cynomys spp.) colonies are unique to prairie and shrub-steppe landscapes. However, widespread eradication, habitat loss, and sylvatic plague (Yersinia pestis) have reduced their numbers by 98% since historical times. Birds associated with prairie dogs also are declining. Potential nest predators, such as coyotes (Canis latrans), swift foxes (Vulpes velox), and badgers (Taxidea taxus), may be attracted to colonies where a high concentration of prairie dogs serve as available prey. Increased abundance of small mammals, including prairie dogs, also may increase the risk of predation for birds nesting on colonies. Finally, because grazing by prairie dogs may decrease vegetation height and canopy cover, bird nests may be easier for predators to locate. In this study, we placed 1,444 artificial ground nests on and off 74 white-tailed prairie dog (C. leucurus) colonies to test the hypothesis that nest predation rates are higher on colonies than at nearby off sites (i.e., uncolonized habitat). We sampled colonies from 27 May to 16 July 1997 at the following 3 complexes: Coyote Basin, Utah and Colorado; Moxa Arch, Wyoming; and Shirley Basin, Wyoming. Differences in daily predation rates between colonies and paired off sites averaged 1.0% (P = 0.060). When converted to a typical 14-day incubation period, predation rates averaged 14% higher on colonies (57.7 ?? 2.7%; ?? ?? SE) than at off sites (50.4 ?? 3.1%). Comparisons of habitat variables on colonies to off sites showed percent canopy cover of vegetation was similar (P = 0.114), percent bare ground was higher on colonies (P 0.288). Although we found the risk of nest predation was higher on white-tailed prairie dog colonies than at off sites, fitness of birds nesting on colonies might depend on other factors that influence foraging success, reproductive success, or nestling survival.

Floral and nesting resources, habitat structure, and fire influence bee distribution across an open-forest gradient

Science.gov (United States)

Grundel, R.; Jean, R.P.; Frohnapple, K.J.; Glowacki, G.A.; Scott, P.E.; Pavlovic, N.B.

2010-01-01

Given bees' central effect on vegetation communities, it is important to understand how and why bee distributions vary across ecological gradients. We examined how plant community composition, plant diversity, nesting suitability, canopy cover, land use, and fire history affected bee distribution across an open-forest gradient in northwest Indiana, USA, a gradient similar to the historic Midwest United States landscape mosaic. When considered with the other predictors, plant community composition was not a significant predictor of bee community composition. Bee abundance was negatively related to canopy cover and positively to recent fire frequency, bee richness was positively related to plant richness and abundance of potential nesting resources, and bee community composition was significantly related to plant richness, soil characteristics potentially related to nesting suitability, and canopy cover. Thus, bee abundance was predicted by a different set of environmental characteristics than was bee species richness, and bee community composition was predicted, in large part, by a combination of the significant predictors of bee abundance and richness. Differences in bee community composition along the woody vegetation gradient were correlated with relative abundance of oligolectic, or diet specialist, bees. Because oligoleges were rarer than diet generalists and were associated with open habitats, their populations may be especially affected by degradation of open habitats. More habitat-specialist bees were documented for open and forest/scrub habitats than for savanna/woodland habitats, consistent with bees responding to habitats of intermediate woody vegetation density, such as savannas, as ecotones rather than as distinct habitat types. Similarity of bee community composition, similarity of bee abundance, and similarity of bee richness between sites were not significantly related to proximity of sites to each other. Nestedness analysis indicated that species

Subterranean ant nests: Trace fossils past and future?

OpenAIRE

Tschinkel, Walter R.

2003-01-01

Many species of ants excavate complex, species-typical nests in soil. The basic structural units of many nests are descending tunnels connecting flattened, generally horizontal chambers of oval to lobed outline. The species-typical structure of many nests results from variation in the size, shape, number and arrangement of these basic elements. Nest architecture can be rendered by filling subterranean nests with a thin slurry of orthodontal plaster, then excavating and reconstructing the hard...

Converting nested algebra expressions into flat algebra expressions

NARCIS (Netherlands)

Paredaens, J.; Van Gucht, D.

1992-01-01

Nested relations generalize ordinary flat relations by allowing tuple values to be either atomic or set valued. The nested algebra is a generalization of the flat relational algebra to manipulate nested relations. In this paper we study the expressive power of the nested algebra relative to its

Workplace, Biographical and Motivation Factors Affecting ...

African Journals Online (AJOL)

This paper presents the findings of a survey on how workplace, biographical and motivational factors affect the organisational commitment of records officers in federal universities in Nigeria. Single stage random sampling, with equal allocation method, was used to administer questionnaire on 300 sampled participants from ...

Psychological factors affecting equine performance

OpenAIRE

McBride, Sebastian D; Mills, Daniel S

2012-01-01

Abstract For optimal individual performance within any equestrian discipline horses must be in peak physical condition and have the correct psychological state. This review discusses the psychological factors that affect the performance of the horse and, in turn, identifies areas within the competition horse industry where current behavioral research and established behavioral modification techniques could be applied to further enhance the performance of animals. In particular, the role of af...

Physical factors affecting the electrically assisted thermal bitumen recovery

Energy Technology Data Exchange (ETDEWEB)

Bogdanov, I.I.; Torres, J.-A.; Kamp, A.M. [CHLOE, University of Pau (France); Corre, B. [CSTJF, Total (France)

2011-07-01

In the heavy oil industry, thermal processes are used to enhance oil recovery by increasing the reservoir temperature which results in better oil mobility. Low frequency heating (LFH) is a technology using electrical conductivity of connate water to propagate current between electrodes, thus generating heat in the reservoir through the Joule effect. During the preheating and production periods, many physical factors may affect the LFH process and the aim of this study was to determine which factors affect the process and how, using a particular pattern of electrodes. Simulations were conducted using the CMG Stars reservoir simulator under different configurations, conditions and parameters. Important physical properties and operational conditions affecting the LFH process were determined and results showed that convection heat, bulk electrical conductivity and power distribution can be improved by salt water circulation. This paper highlighted the physical factors affecting LFH efficiency and these findings will be useful for future process design.

Biology of a trap-nesting wasp of one species the ground-nesting Liris (Hymenoptera: Crabronidae from the Atlantic Forest of southern Brazil

Directory of Open Access Journals (Sweden)

Camila Cristina Ferreira da Costa

Full Text Available ABSTRACT Studies on the nesting biology of Liris are restricted to a few notes and observations on ground-nesting species. There are no studies of this kind about Brazilian species. We investigated and described the nesting biology of Liris sp. obtained by trap-nests that were installed at an area of Atlantic Forest vegetation (25°10'S, 48°18'W in southern Brazil. The nests of Liris sp. are built with a variety of plant debris. They usually have one cell, but may have up to two. Nests do not show vestibular or intercalary cells. Immatures have a hard cocoon made with the silk they produce, mixed with the fine sand and sawdust left by the adult female at the bottom of the cell. No nest parasites were observed. The wasps did not go through diapause at the prepupal stage, and emerged within 36 to 46 days after nests were collected from the field. There was no emergence of male wasps. Even though Liris sp. nest in preexisting cavities, they resemble ground-nesting species of the same genus in their habits, nest architecture, and development characteristics. The absence of males in our samples might be related to nest diameter. The eggs from which males hatch can be laid in smaller burrows than those available at the present study. We believe that the hardiness of the cocoon is the species' main strategy against parasites, although it is complemented by the camouflage provided by the nest closure. We suggest that a broader comparison of the nesting biology of Liris Fabricius, 1804 should be carried out, leading to a better understanding of the evolution of nests in the genus.

Ants show a leftward turning bias when exploring unknown nest sites.

Science.gov (United States)

Hunt, Edmund R; O'Shea-Wheller, Thomas; Albery, Gregory F; Bridger, Tamsyn H; Gumn, Mike; Franks, Nigel R

2014-12-01

Behavioural lateralization in invertebrates is an important field of study because it may provide insights into the early origins of lateralization seen in a diversity of organisms. Here, we present evidence for a leftward turning bias in Temnothorax albipennis ants exploring nest cavities and in branching mazes, where the bias is initially obscured by thigmotaxis (wall-following) behaviour. Forward travel with a consistent turning bias in either direction is an effective nest exploration method, and a simple decision-making heuristic to employ when faced with multiple directional choices. Replication of the same bias at the colony level would also reduce individual predation risk through aggregation effects, and may lead to a faster attainment of a quorum threshold for nest migration. We suggest the turning bias may be the result of an evolutionary interplay between vision, exploration and migration factors, promoted by the ants' eusociality.

Harpy eagle (Harpia harpyja) nesting in manipulated forests

Science.gov (United States)

Alvarez, E.; Ellis, D.H.

1994-01-01

Continental records point to shooting, removal of young and destruction of nests as the primary conservation problems for harpy eagles (Harpia harpyja); bird-observer visits are a new source of concern. Nesting events are roughly 3 yr apart. Nests are used during and after intensive manipulation of the surrounding habitat, and minimum distance between active sites was 3-5 km. In nine nesting sites along a 100-km stretch of the Imalaca Mountains in Venezuela, we fitted five fledglings with satellite-tracked tags from NASA. One of these birds was hacked with the help of the loggers who destroyed its nest. All these nests were active while logging ensued. Out of three renesting attempts, one failed when the nest collapsed. We salvaged two additional fledglings found in captivity. We are monitoring five nests in the buffer area of the Darien National Park in Panama, all within 3 km of human settlements where trees are regularly felled for firewood, lumber, and to clear more cropland. Eagles have been killed at two sites, a third site remains inactive since 1991, and the other two nests currently have fledglings.

Simulating large-scale spiking neuronal networks with NEST

OpenAIRE

Schücker, Jannis; Eppler, Jochen Martin

2014-01-01

The Neural Simulation Tool NEST [1, www.nest-simulator.org] is the simulator for spiking neural networkmodels of the HBP that focuses on the dynamics, size and structure of neural systems rather than on theexact morphology of individual neurons. Its simulation kernel is written in C++ and it runs on computinghardware ranging from simple laptops to clusters and supercomputers with thousands of processor cores.The development of NEST is coordinated by the NEST Initiative [www.nest-initiative.or...

Latent factors and route choice behaviour

DEFF Research Database (Denmark)

Prato, Carlo Giacomo

. A reliable dataset was prepared through measures of internal consistency and sampling adequacy, and data were analyzed with a proper application of factor analysis to the route choice context. For the dataset obtained from the survey, six latent constructs affecting driver behaviour were extracted and scores...... on each factor for each survey participant were calculated. Path generation algorithms were examined with respect to observed behaviour, through a measure of reproduction with deterministic techniques of the routes indicated in the answers to the survey. Results presented evidence that the majority...... and Link Nested Logit. Estimates were produced from model specifications that considered level-of-service, label and facility dummy variables. Moreover, a modelling framework was designed to represent drivers’ choices as affected by the latent constructs extracted with factor analysis. Previous experience...

Density and Distribution of Xylocopa Nests (Hymenoptera: Apidae) in Caatinga Areas in the Surroundings of Passion Fruit Crops.

Science.gov (United States)

Martins, C F; de Siqueira, K M M; Kiill, L H P; Sá, I I S; Aguiar, C M L

2014-08-01

Due to their importance as pollinators of many plant species, this study aimed to know the nest density, spatial distribution, and nesting substrates used by Xylocopa species in the Caatinga, a xerophilous vegetation of Northeastern Brazil. Three areas of Caatinga in the surroundings of passion fruit crops were sampled. The bee species found in these areas were Xylocopa grisescens Lepeletier and Xylocopa frontalis (Olivier). All nests were in Commiphora leptophloeos (Burseraceae) trees (n = 113). Phytosociological analysis showed that this tree species presented the highest absolute density (212.5 individuals/ha) and index of importance value (52.7). The distribution pattern of the C. leptophloeos was aggregated. The nests were located in dead and dried branches with an average diameter of 5.3 ± 2.0 cm (n = 43). The mean number of nests/tree was 3.1 ± 2.8 (n = 113). The less disturbed area showed 6.7 nests/ha and 4.2 nests/tree. In the disturbed areas, 0.9 nests/ha and 2.4 to 2.7 nests/tree were observed. The availability of substrate for nesting in the studied areas and its importance as a limiting factor for nesting are discussed.

Gregarious nesting - An anti-predator response in laying hens

DEFF Research Database (Denmark)

Riber, Anja Brinch

2012-01-01

Gregarious nesting can be defined as a behaviour that occurs when a laying hen (Gallus gallus domesticus) given the choice between an occupied and an unoccupied nest site chooses the occupied nest site. It occurs frequently in flocks of laying hens kept under commercial conditions, contrasting...... the behaviour displayed by feral hens that isolate themselves from the flock during nesting activities. What motivates laying hens to perform gregarious nesting is unknown. One possibility is that gregarious nesting is an anti-predator response to the risk of nest predation emerging from behavioural flexibility...

Investigation of Factors Affecting Microdialysis Probe Delivery and ...

African Journals Online (AJOL)

HP

Purpose: To investigate in vitro the factors affecting microdialysis probe delivery and recovery of puerarin . Methods: ... methods. Factors such as drug concentration, stirring speed, additives and length of membrane were ... The high performance liquid chromatography ..... Pharmacokinetic Modeling to Investigate Regional.

Personality factors and adult attachment affecting job mobility

NARCIS (Netherlands)

van Vianen, A.E.M.; Feij, J.A.; Krausz, M.; Taris, R.

2003-01-01

Past research has revealed that individuals' job mobility is affected by factors such as job satisfaction, specific career enhancing attributes and job availability. This study examined personality factors predicting voluntary internal and external job mobility. Three types of voluntary job mobility

Trap-nests for stingless bees (Hymenoptera, Meliponini)

OpenAIRE

Oliveira , Ricardo; Menezes , Cristiano; Soares , Ademilson; Fonseca , Vera

2012-01-01

International audience; Most stingless bee species build their nests inside tree hollows. In this paper, we present trap-nest containers which simulate nesting cavities so as to attract swarms of stingless bees. Although regularly used by stingless bee beekeepers in Brazil, this technique to obtain new colonies has not yet been systematically studied. We used two different types of trap-nests (plastic and cardboard) of four different sizes (0.5, 1.0, 2.0, and 3.0 L) containing propolis extrac...

Parallel factor analysis PARAFAC of process affected water

Energy Technology Data Exchange (ETDEWEB)

Ewanchuk, A.M.; Ulrich, A.C.; Sego, D. [Alberta Univ., Edmonton, AB (Canada). Dept. of Civil and Environmental Engineering; Alostaz, M. [Thurber Engineering Ltd., Calgary, AB (Canada)

2010-07-01

A parallel factor analysis (PARAFAC) of oil sands process-affected water was presented. Naphthenic acids (NA) are traditionally described as monobasic carboxylic acids. Research has indicated that oil sands NA do not fit classical definitions of NA. Oil sands organic acids have toxic and corrosive properties. When analyzed by fluorescence technology, oil sands process-affected water displays a characteristic peak at 290 nm excitation and approximately 346 nm emission. In this study, a parallel factor analysis (PARAFAC) was used to decompose process-affected water multi-way data into components representing analytes, chemical compounds, and groups of compounds. Water samples from various oil sands operations were analyzed in order to obtain EEMs. The EEMs were then arranged into a large matrix in decreasing process-affected water content for PARAFAC. Data were divided into 5 components. A comparison with commercially prepared NA samples suggested that oil sands NA is fundamentally different. Further research is needed to determine what each of the 5 components represent. tabs., figs.

Endophagy of biting midges attacking cavity-nesting birds.

Science.gov (United States)

Votýpka, J; Synek, P; Svobodová, M

2009-09-01

Feeding behaviour, host preferences and the spectrum of available hosts determine the role of vectors in pathogen transmission. Feeding preferences of blood-feeding Diptera depend on, among others factors, the willingness of flies to attack their hosts either in the open (exophagy) or in enclosed places (endophagy). As far as ornithophilic blood-feeding Diptera are concerned, the biting midges (Diptera: Ceratopogonidae) and blackflies (Diptera: Simuliidae) are generally considered to be strictly exophagous. We determined which blood-sucking Diptera enter nest cavities and feed on birds by placing sticky foil traps inside artificial nest boxes. A total of 667 females of eight species of biting midges of the genus Culicoides (Latreille, 1809) were captured on traps during 2006-2007, with Culicoides truncorum (Edwards, 1939) being the dominant species. DNA blood analyses of blood-engorged females proved that midges actually fed on birds nesting in the boxes. Three species were identified as endophagous: Culicoides truncorum, Culicoides pictipennis (Staeger, 1839), and Culicoides minutissimus (Zetterstedt, 1855). Our study represents the first evidence that ornithophilic biting midges are endophagous. The fact that we caught no blackflies in the bird boxes supports the exophagy of blackflies. We believe that our findings are important for surveillance programmes focusing on Diptera that transmit various bird pathogens.

Quantum critical fluctuations due to nested Fermi surface: The case of spinless fermions

International Nuclear Information System (INIS)

Schlottmann, P.

2007-01-01

A quantum critical point (QCP) can be obtained by tuning the critical temperature of a second-order phase transition to zero. A simple model of spinless fermions with nested Fermi surface leading to a charge density wave is considered. The QCP is obtained by tuning the nesting mismatch of the Fermi surface, which has the following consequences: (i) For the tuned QCP, the specific heat over T and the effective mass increase with the logarithm of the temperature as T is lowered. (ii) For the tuned QCP the linewidth of the quasi-particles is sublinear in T and ω. (iii) The specific heat and the linewidth display a crossover from non-Fermi liquid (∼T) to Fermi liquid (∼T 2 ) behavior with increasing nesting mismatch and decreasing temperature. (iv) For the tuned QCP, the dynamical charge susceptibility has a quasi-elastic peak with a linewidth proportional to T. (v) For non-critical Fermi vector mismatch the peak is inelastic. (vi) While the specific heat and the quasi-particle linewidth are only weakly dependent on the geometry of the nested Fermi surfaces, the momentum-dependent dynamical susceptibility is expected to be affected by the shape of the Fermi surface

Factors affecting the performance of professional nurses in Namibia

Directory of Open Access Journals (Sweden)

Magdalene H. Awases

2013-04-01

Objectives: The aim of the present study was to identify factors affecting the performance of professional nurses in Namibia. Method: A quantitative, descriptive survey was used to collect data by means of a questionnaire. A random sample of 180 professional nurses was selected from six hospitals in three regions of Namibia. Results: Factors affecting the performance of nurses negatively were identified such as: lack of recognition of employees who are performing well, quality performance outcomes and an absence of a formal performance appraisal system and poor working conditions. Various factors contribute to both the positive and negative performance of professional nurses in Namibia. Strategies were developed for addressing the negative factors that could positively affect the performance of professional nurses in Namibia. Conclusions: This study emphasises the importance of developing strategies to promote the performance of nurses; build knowledge and expertise; develop mechanisms for improving the performance of nurses; expand leadership and management capacity; and generate information and knowledge through research.

Elevated temperatures are associated with stress in rooftop-nesting Common Nighthawk (Chordeiles minor) chicks.

Science.gov (United States)

Newberry, Gretchen N; Swanson, David L

2018-01-01

Grasslands and riparian forests in southeastern South Dakota have been greatly reduced since historical times, primarily due to conversion to row-crop agriculture. Common Nighthawk ( Chordeiles minor ) nesting habitat includes grasslands, open woodlands and urban rooftops, but nesting sites in southeastern South Dakota are confined to rooftops, as natural nesting habitat is limited. Nighthawks nesting on exposed rooftop habitats may encounter thermal conditions that increase operative temperatures relative to vegetated land cover types. Mean humidity has increased and mean wind speed and cloud cover have decreased during the nighthawk breeding season from 1948 to 2016 in southeastern South Dakota. These changes might contribute to increasing operative temperatures at exposed rooftop nest sites and this could influence chick condition. We studied nest micro-climate and the plasma stress response for 24 rooftop-nesting nighthawk chicks from 17 nests during 2015 and 2016. High humidity prior to blood collection reduced both baseline and stress-induced plasma corticosterone (CORT). In contrast, high maximum temperatures during the day before sampling increased stress-induced CORT. The magnitude of the chick stress response was significantly negatively related to maximum wind speed for the week prior to CORT measurement. Other weather and micro-climate variables were not significant effectors of CORT metrics. Most chicks had low baseline CORT and were able to mount a stress response, but a subset of chicks ( n = 4) showed elevated baseline CORT and a negative association between the magnitude of stress response and ambient temperature. For this subset, mean ambient temperature for the day before sampling was significantly higher (2.3°C) than for chicks with typical baseline CORT levels. These data suggest that regional climate change trends could affect the ability of nighthawk chicks to mount a stress response, which, in turn, might influence the susceptibility of

Synchronised provisioning at the nest: parental coordination over care in a socially monogamous species

Directory of Open Access Journals (Sweden)

Erica P. van Rooij

2013-12-01

Full Text Available Bi-parental care is very common in birds, occurring in over 90% of species, and is expected to evolve whenever the benefits of enhanced offspring survival exceed the costs to both parents of providing care. In altricial species, where the nestlings are entirely dependent on the parents for providing food until fledging, reproductive success is related to the capacity of the parents to provision the offspring at the nest. The degree to which parents synchronise their visits to the nest is rarely considered by studies of bi-parental care, and yet may be an important component of parental care, affecting the outcome of the reproductive attempt, and the dynamics of sexual conflict between the parents. Here we studied this aspect of parental care in the long-tailed finch (Poephila acuticauda, a socially monogamous estrildid finch. We monitored parental nest visit rates and the degree of parental visit synchrony, and assessed their effects on reproductive success (e.g., brood size, number of offspring fledged and nestling growth.The frequency of nest visits in a day was low in this species (<1 visit/h, but there was a high level of synchrony by the two partners with 73% of visits made together. There was a correlation between the proportion of visits that were made by the pair together and the size of the brood at hatching, although it was not related to the number of fledglings a pair produced, or the quality of those offspring. We suggest that nest visit synchrony may primarily be driven by the benefit of parents being together whilst foraging away from the nest, or may reduce nest predation by reducing the level of activity around the nest throughout the day.

Colour preferences in nest-building zebra finches.

Science.gov (United States)

Muth, Felicity; Steele, Matthew; Healy, Susan D

2013-10-01

Some bird species are selective in the materials they choose for nest building, preferring, for example, materials of one colour to others. However, in many cases the cause of these preferences is not clear. One of those species is the zebra finch, which exhibits strong preferences for particular colours of nest material. In an attempt to determine why these birds strongly prefer one colour of material over another, we compared the preferences of paired male zebra finches for nest material colour with their preferences for food of the same colours. We found that birds did indeed prefer particular colours of nest material (in most cases blue) but that they did not generally prefer food of one colour over the other colours. It appears, then, that a preference for one colour or another of nest material is specific to the nest-building context. This article is part of a Special Issue entitled: insert SI title. Copyright © 2013 Elsevier B.V. All rights reserved.

Effects of temperature and precipitation on grassland bird nesting success as mediated by patch size.

Science.gov (United States)

Zuckerberg, Benjamin; Ribic, Christine A; McCauley, Lisa A

2018-02-06

Grassland birds are declining faster than any other bird guild across North America. Shrinking ranges and population declines are attributed to widespread habitat loss and increasingly fragmented landscapes of agriculture and other land uses that are misaligned with grassland bird conservation. Concurrent with habitat loss and degradation, temperate grasslands have been disproportionally affected by climate change relative to most other terrestrial biomes. Distributions of grassland birds often correlate with gradients in climate, but few researchers have explored the consequences of weather on the demography of grassland birds inhabiting a range of grassland fragments. To do so, we modeled the effects of temperature and precipitation on nesting success rates of 12 grassland bird species inhabiting a range of grassland patches across North America (21,000 nests from 81 individual studies). Higher amounts of precipitation in the preceding year were associated with higher nesting success, but wetter conditions during the active breeding season reduced nesting success. Extremely cold or hot conditions during the early breeding season were associated with lower rates of nesting success. The direct and indirect influence of temperature and precipitation on nesting success was moderated by grassland patch size. The positive effects of precipitation in the preceding year on nesting success were strongest in relatively small grassland patches and had little effect in large patches. Conversely, warm temperatures reduced nesting success in small grassland patches but increased nesting success in large patches. Mechanisms underlying these differences may be patch-size-induced variation in microclimates and predator activity. Although the exact cause is unclear, large grassland patches, the most common metric of grassland conservation, appears to moderate the effects of weather on grassland-bird demography and could be an effective component of climate-change adaptation. �

Turkey habitat use and nesting characteristics in ponderosa pine

Science.gov (United States)

Mark A. Rumble; Stanley H. Anderson

1987-01-01

Turkeys (Meleagris gallapovo) selected nest sites that provided good horizontal concealment. Rock or rock outcrops were selected most frequently for nest concealment on first-nest attempts. Renest attempts showed a selection preference for shrubs as nest cover; most of these were located in meadows. Nesting success doubled for renests versus first...

Response of predators to Western Sandpiper nest exclosures

Science.gov (United States)

Niehaus, Amanda C.; Ruthrauff, Daniel R.; McCaffery, Brian J.

2004-01-01

In 2001, predator exclosures were used to protect nests of the Western Sandpiper (Calidris mauri) in western Alaska. During the exclosure experiment, nest contents in exclosures had significantly higher daily survival rates than control nests, however, late in the study predators began to cue in on exclosures and predate the nest contents. An Arctic Fox (Alopex lagopus) dug under one exclosure and took the newly hatched chicks, and Long-tailed Jaegers (Stercorarius longicaudus) learned to associate exclosures with active nests and repeatedly visited them. The jaegers attempted to gain access to exclosed nests and pursued adult sandpipers as they emerged from the exclosures. The exclosures were removed to reduce potential mortality to adult and young sandpipers, but subsequently, post-exclosure nests had lower daily survival rates than controls during the same time period. Predation of post-exclosure eggs and chicks highlighted the lasting influence of the exclosure treatment on offspring survival because predators probably remembered nest locations. Researchers are urged to use caution when considering use of predator exclosures in areas where jaegers occur.

Incorporation of cigarette butts into nests reduces nest ectoparasite load in urban birds: new ingredients for an old recipe?

Science.gov (United States)

Suárez-Rodríguez, Monserrat; López-Rull, Isabel; Garcia, Constantino Macías

2013-02-23

Birds are known to respond to nest-dwelling parasites by altering behaviours. Some bird species, for example, bring fresh plants to the nest, which contain volatile compounds that repel parasites. There is evidence that some birds living in cities incorporate cigarette butts into their nests, but the effect (if any) of this behaviour remains unclear. Butts from smoked cigarettes retain substantial amounts of nicotine and other compounds that may also act as arthropod repellents. We provide the first evidence that smoked cigarette butts may function as a parasite repellent in urban bird nests. The amount of cellulose acetate from butts in nests of two widely distributed urban birds was negatively associated with the number of nest-dwelling parasites. Moreover, when parasites were attracted to heat traps containing smoked or non-smoked cigarette butts, fewer parasites reached the former, presumably due to the presence of nicotine. Because urbanization changes the abundance and type of resources upon which birds depend, including nesting materials and plants involved in self-medication, our results are consistent with the view that urbanization imposes new challenges on birds that are dealt with using adaptations evolved elsewhere.

Daily nest survival rates of Gunnison Sage-Grouse (Centrocercus minimus): assessing local- and landscape-scale drivers

Science.gov (United States)

Stanley, Thomas R.; Aldridge, Cameron L.; Joanne Saher,; Theresa Childers,

2015-01-01

The Gunnison Sage-Grouse (Centrocercus minimus) is a species of conservation concern and is a candidate for listing under the U.S. Endangered Species Act because of substantial declines in populations from historic levels. It is thought that loss, fragmentation, and deterioration of sagebrush (Artemisia spp.) habitat have contributed to the decline and isolation of this species into seven geographically distinct subpopulations. Nest survival is known to be a primary driver of demography of Greater Sage-Grouse (C. urophasianus), but no unbiased estimates of daily nest survival rates (hereafter nest survival) exist for Gunnison Sage-Grouse or published studies identifying factors that influence nest survival. We estimated nest survival of Gunnison Sage-Grouse for the western portion of Colorado's Gunnison Basin subpopulation, and assessed the effects and relative importance of local- and landscape-scale habitat characteristics on nest survival. Our top performing model was one that allowed variation in nest survival among areas, suggesting a larger landscape-area effect. Overall nest success during a 38-day nesting period (egg-laying plus incubation) was 50% (daily survival rate; SE  =  0.982 [0.003]), which is higher than previous estimates for Gunnison Sage-Grouse and generally higher than published for the closely related Greater Sage-Grouse. We did not find strong evidence that local-scale habitat variables were better predictors of nest survival than landscape-scale predictors, nor did we find strong evidence that any of the habitat variables we measured were good predictors of nest survival. Nest success of Gunnison Sage-Grouse in the western portion of the Gunnison Basin was higher than previously believed.

Blood group AB and factor V Leiden as risk factors for pre-eclampsia: a population-based nested case-control study.

Science.gov (United States)

Hiltunen, Leena M; Laivuori, Hannele; Rautanen, Anna; Kaaja, Risto; Kere, Juha; Krusius, Tom; Paunio, Mikko; Rasi, Vesa

2009-06-01

Pre-eclampsia is an important cause of maternal morbidity and mortality. Its etiology is still unknown. Clinical symptoms correlate with activation of coagulation and inherited thrombophilia has been associated with pre-eclampsia. ABO blood group has been associated with thrombotic disorders and pre-eclampsia. We assessed ABO blood group, seven thrombophilia associated polymorphisms, and anti-beta2-glycoprotein I antibodies as risk factors for pre-eclampsia. We performed a population-based nested case-control study of 100,000 consecutive pregnancies in Finland. Cases and controls were identified by combining national registers and medical records were reviewed. We studied 248 cases fulfilling strict criteria for pre-eclampsia and 679 controls. Severe pre-eclampsia, early pre-eclampsia, and pre-eclampsia with intra-uterine growth restriction (IUGR) were analyzed separately. Blood group AB increased the risk for pre-eclampsia as a whole (OR 2.1, 95% CI 1.3-3.5), and in the three subgroups (OR 2.3, 3.8, 3.4; 95% CI 1.3-3.9, 2.0-7.1, 1.6-7.1). FV Leiden increased the risk as a whole (OR 1.7, 95% CI 0.8-3.9), and in the three subgroups, although not statistically significantly. Anti-beta2-glycoprotein I antibodies were not associated with pre-eclampsia. High body mass index, diabetes, first pregnancy, and twin pregnancy increased the risk from 1.5-fold to 8.2-fold. Our results confirm and extend the prior observation of blood group AB being a risk factor for pre-eclampsia. ABO blood group is known from all pregnant women. The value of blood group as risk factor for pre-eclampsia should be further assessed in prospective studies. In this study, FV Leiden was not statistically significant risk factor.

Production performance, use of nest box, and external appearance of two strains of laying hens kept in conventional and enriched cages.