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Sample records for oystercatcher haematopus ostralegus

  1. Egg size, egg composition and reproductive success in the Oystercatcher Haematopus ostralegus

    NARCIS (Netherlands)

    Jager, TD; Hulscher, JB; Kersten, M.

    2000-01-01

    We investigated the relationship between egg size and composition and their subsequent effects on hatching and fledging success in Eurasian Oystercatchers Haematopus ostralegus on the island of Schiermonnikoog (53 degrees 30'N, 06 degrees 10'E) in the Dutch Wadden Sea between 1986 and 1990. Egg size

  2. Growth, fledging success and post-fledging survival of juvenile Oystercatchers Haematopus ostralegus

    NARCIS (Netherlands)

    Kersten, Marcel; Brenninkmeijer, Alex

    We studied the consequences of differences in growth rate on the subsequent survival of Oystercatcher Haematopus ostralegus chicks. Fledging success increased sharply with growth rate, from zero in chicks growing at less than 6 g per day to about 85% in chicks growing at more than 10 g per day. The

  3. Effects of territory quality, food availability and sibling competition on the fledging success of oystercatchers (Haematopus ostralegus)

    NARCIS (Netherlands)

    Heg, Dik; van der Velde, Marco

    We investigated the fledging probability of oystercatcher, Haematopus ostralegus, chicks as a function of hatching order, brood size, territory quality and food availability. Sibling dominance was related to the hatching order in both low- ('leapfrogs') and high-quality ('residents') territories.

  4. Fitness consequences of divorce in the oystercatcher, Haematopus ostralegus

    NARCIS (Netherlands)

    Heg, Dik; Bruinzeel, Leo W.; Ens, Bruno J.

    We investigated the fitness consequences of divorce in oystercatchers. We made a distinction between two types of divorce: in desertions the disruption of the pair bond is initiated by one of the pair members, and in usurpations by a conspecific individual. Survival and reproduction prospects for

  5. Rearing conditions determine offspring survival independent of egg quality : A cross-foster experiment with Oystercatchers Haematopus ostralegus

    NARCIS (Netherlands)

    van de Pol, Martijn; Bakker, T; Saaltink, DJ; Verhulst, S; Saaltink, Dirk-Jan

    Variation in rearing conditions, due either to parental or to environmental quality, can result in offspring of different quality (e.g. body condition, immune function). However, evidence is accumulating that egg size and composition can also affect offspring quality. In Oystercatchers Haematopus

  6. Why oystercatchers Haematopus ostralegus cannot meet their daily energy requirements in a single low water period

    NARCIS (Netherlands)

    Zwarts, L; Ens, B.J.; GossCustard, JD; Hulscher, JB; Kersten, M.

    1996-01-01

    Captive Oystercatchers consume daily 25-40 g dry flesh or 550-850 kJ, of which they metabolize 450-700 kJ. Free-living Oystercatchers eat more than captive birds but, contrary to expectation, this is not due to greater activity costs but to a higher body weight. When body weights are equal,

  7. Oystercatcher Haematopus ostralegus winter mortality in The Netherlands : The effect of severe weather and food supply

    NARCIS (Netherlands)

    Camphuysen, CJ; Ens, B.J.; Heg, Dierik; Hulscher, JB; VanderMeer, J; Smit, CJ

    1996-01-01

    Wintering Oystercatchers in The Netherlands are concentrated in the Wadden Sea (c. 200 000), with substantial numbers in the Delta area (c. 90 000). Only 1% of the total wintering population is normally found along the North Sea coast. Cold-rushes under severe winter conditions lead to a reduction

  8. Seasonal and annual variation in body weight, nutrient stores and mortality of Oystercatchers Haematopus ostralegus

    NARCIS (Netherlands)

    Zwarts, L.; Hulscher, J.B.; Koopman, K.; Piersma, T.; Zegers, P.M.

    1996-01-01

    The average body weight of Oystercatchers captured in the Dutch Wadden Sea and ajoining breeding areas varies between 520 g in mid summer and 620 g in mid winter, but the individual differences remain large: between 450 and 650 g in summer and 500 and 725 g in winter. A part of this variation can be

  9. Prey selection of a captive Oystercatcher Haematopus ostralegus hammering Mussels Mytilus edulis from the ventral side

    NARCIS (Netherlands)

    Ens, Bruno J.; Alting, D

    1996-01-01

    We studied prey choice of a captive Oystercatcher:hat hammered Mussels from the ventral side. The results replicate previous findings that ventral hammerers select Mussels of intermediate size, select against thick-shelled Mussels, abandon an increasing proportion of Mussels with increasing size and

  10. Body weight in relation to variation in body size of Oystercatchers Haematopus ostralegus

    NARCIS (Netherlands)

    Zwarts, L; Hulscher, JB; Koopman, K; Zegers, PM

    1996-01-01

    This paper analyses the relationships between body weight in the Oystercatcher and two measures of its body size, bill length and wing length. The weight variation between individuals due to differences in body size is nearly as large as the seasonal variation in body weight within individuals. Wing

  11. Weight loss in Oystercatchers Haematopus ostralegus on the roost and after capture

    NARCIS (Netherlands)

    Zwarts, L; Hulscher, JB; Zegers, PM

    1996-01-01

    This paper analyses the weight loss in Oystercatchers on the roost and after capture and attempts to investigate to what degree this weight loss is due to defecation of digested food, to dehydration and to utilisation of nutrient stores. The study emphasizes the need to record weight changes

  12. On the timing of foraging flights by oystercatchers, haematopus ostralegus, on tidal mudflats

    Science.gov (United States)

    Daan, Serge; Koene, Paul

    The tidal movements of flocks of oystercatchers foraging on mudflats at low tide and roosting inland behind a dike at high tide were studied and the effects of day-to-day variations in the time of mudflat exposure by ebb analysed. High mean water levels and short low tides led to reduced intake during low water due to increased bird densities in addition to temporal constraints (Fig. 4). Increased feeding around the roost apparently compensated for some of the reduced intake (Figs 6 ad 7) although accurate intake measurements could be made for foraging on the tidal flats only. It is argued that optimal timing of foraging flights to coincide with exposure of the mussel banks would contribute to exploitation of this tidal food source. The median departure time from the roosts relative to the time of mudflat exposure was early on days when the tide went out late and late when the tide was early (Figs 8 and 9). Daily variations in departure time were predicted by the daily variations in tabulated high water times, but not by variations in mudflat exposure or coverage (Fig. 10). The conclusion is drawn that the birds employ a timing mechanism not directly associated with the tidal water movements. In some pilot experiments in caged oystercatchers, feeding schedules elicitated feeling attempts in anticipation of expected food. The anticipatory patterns were different for fixed and tidally shifting daily food schedules, and moreover differed between the two feeding times per day (Figs 12 and 13). Five possible mechanisms for tidal anticipation are discussed, making use either of unknown exogenous cues, or of—likewise unknown—endogenous timers of hourglass type of rhythmic with circatidal, circalunadian or circadian period. Experimental tests for these possibilities are outlined.

  13. Food intake of Oystercatchers Haematopus ostralegus by day and by night measured with an electronic nest balance

    NARCIS (Netherlands)

    Kersten, M.

    1996-01-01

    We developed a model to calculate food intake by Oystercatchers from their weight gain between two incubation spells and correcting for the amount of excreta voided before the bird returned to its nest. The model predictions agreed well with estimated food consumption based on direct observations in

  14. Daily metabolized energy consumption of Oystercatchers Haematopus ostralegus feeding on larvae of the crane fly Tipula paludosa

    NARCIS (Netherlands)

    Zwarts, L; Blomert, AM

    1996-01-01

    Oystercatchers feeding on grassland in spring mainly take leatherjackets, the larvae of the crane fly Tipula paludosa. The birds roost at night and feed for 40 to 60% of the daylight period. Their intake rate during feeding is 1 to 1.5 mg AFDW or 20 to 30 J s(-1), which is rather low compared to the

  15. Helminth parasites of the digestive tract of the oystercatcher, Haematopus ostralegus, in the Wadden Sea, The Netherlands

    Science.gov (United States)

    Borgsteede, F. H. M.; Van den Broek, E.; Swennen, C.

    The digestive tracts of 90 oystercatchers (equal numbers of males and females and of juveniles, subadults and adults) wintering in the Dutch Wadden Sea were examined for helminth parasites. The nematodes Capillaria sp. (36.7%) and Streptocara crassicauda (7.8%) were found in the stomach. Unidentified cestodes (76.7%) and the trematodes Psilostomum brevicolle (42.2%), Notocotylus sp. (81.1%), and unidentified gymnophallids (100%) were found in the intestine and caeca. Two birds were infected with Gymnophallidae only, while all other birds contained additional helminth species. Compared with subadult and adult birds, the juveniles had significantly more infections with Capillaria sp. and cestodes. Moreover, the juveniles were infected with a greater variety of species. No further relation was found between the presence of helminths or worm numbers and age groups or sexes of birds.

  16. Breeding phenology of African Black Oystercatchers Haematopus ...

    African Journals Online (AJOL)

    The timing of the start and duration of breeding and the effect of these on breeding productivity were analysed for African Black Oystercatchers Haematopus moquini on Robben Island, South Africa, over three breeding seasons from 2001 to 2004. African Black Oystercatchers have a long breeding season, from November ...

  17. Predicting seasonal and annual fluctuations in the local exploitation of different prey by Oystercatchers Haematopus ostralegus : A ten-year study in the Wadden Sea

    NARCIS (Netherlands)

    Zwarts, L; Wanink, JH; Ens, B.J.

    1996-01-01

    We predict the intake rate and prey choice of Oystercatchers feeding along the Frisian coast, Dutch Wadden Sea, combining the optimal prey choice model (Charnov 1976) with detailed measurements of the widely fluctuating food supply. Assuming that the birds maximize their intake rate, the birds

  18. Trends in African Black Oystercatcher Haematopus moquini ...

    African Journals Online (AJOL)

    Although human activity has increased in many parts of the species' breeding range, oystercatchers may be benefiting from an increase in the extent of Marine Protected Areas as well as an improved food supply provided by an alien invasive mussel, Mytilus galloprovincialis. The study reassesses the global population (last ...

  19. Hurricane disturbance benefits nesting American Oystercatchers (Haematopus palliatus)

    Science.gov (United States)

    Simons, Theodore R.; Schulte, Shiloh A.

    2016-01-01

    Coastal ecosystems are under increasing pressure from human activity, introduced species, sea level rise, and storm activity. Hurricanes are a powerful destructive force, but can also renew coastal habitats. In 2003, Hurricane Isabel altered the barrier islands of North Carolina, flattening dunes and creating sand flats. American Oystercatchers (Haematopus palliatus) are large shorebirds that inhabit the coastal zone throughout the year. Alternative survival models were evaluated for 699 American Oystercatcher nests on North Core Banks and South Core Banks, North Carolina, USA, from 1999–2007. Nest survival on North Core Banks increased from 0.170 (SE = 0.002) to 0.772 (SE = 0.090) after the hurricane, with a carry-over effect lasting 2 years. A simple year effects model described nest survival on South Core Banks. Habitat had no effect on survival except when the overall rate of nest survival was at intermediate levels (0.300–0.600), when nests on open flats survived at a higher rate (0.600; SE = 0.112) than nests in dune habitat (0.243; SE = 0.094). Predator activity declined on North Core Banks after the hurricane and corresponded with an increase in nest survival. Periodic years with elevated nest survival may offset low annual productivity and contribute to the stability of American Oystercatcher populations.

  20. Parental correlates of offspring sex ratio in Eurasian Oystercatchers

    NARCIS (Netherlands)

    Heg, D.; Dingemanse, NJ; Lessells, CM; Mateman, AC

    2000-01-01

    We investigated hatchling and fledgling sex ratios in Eurasian Oystercatchers (Haematopus ostralegus) using random amplified polymorphic DNA markers. The overall hatchling (53% males, n = 374 hatchlings from 177 broods) and fledgling (49% males, n = 51) sex ratio did not differ significantly from

  1. The American Oystercatcher (Haematopus palliatus) Working Group: 15 years of collaborative focal species research and management

    Science.gov (United States)

    Simons, Theodore R.

    2017-01-01

    The American Oystercatcher (Haematopus palliatus) Working Group formed spontaneously in 2001 as coastal waterbird biologists recognized the potential for American Oystercatchers to serve as focal species for collaborative research and management. Accomplishments over the past 15 years include the establishment of rangewide surveys, color-banding protocols, mark-resight studies, a revision of the Birds of North America species account, and new mechanisms for sharing ideas and data. Collaborations among State, Federal, and private sector scientists, natural resource managers, and dedicated volunteers have provided insights into the biology and conservation of American Oystercatchers in the United States and abroad that would not have been possible without the relationships formed through the Working Group. These accomplishments illustrate how broad collaborative approaches and the engagement of the public are key elements of effective shorebird conservation programs.

  2. 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

  3. Experimental evidence for effects of human disturbance on foraging and parental care in oystercatchers

    NARCIS (Netherlands)

    Verhulst, S; Oosterbeek, K; Ens, B.J.

    2001-01-01

    We carried out two experiments to quantify effects of human disturbance on foraging and parental care in European oystercatchers (Haematopus ostralegus). In experiment 1, pairs incubating a clutch were disturbed on their feeding territory on the mudflat. Disturbance significantly reduced the

  4. State-dependent life-history strategies : A long-term study on oystercatchers

    NARCIS (Netherlands)

    van de Pol, Martijn

    2006-01-01

    The research described in this thesis is part of a long-term field study on free-living Oystercatchers (Haematopus ostralegus), on the Dutch Wadden Sea island of Schiermonnikoog.The study was started in 1983 by Jan Hulscher, and since then a lineage of PhDstudents has investigated life-history

  5. A global assessment of the conservation status of the American Oystercatcher Haematopus palliatus

    Science.gov (United States)

    Clay, Robert P.; Lesterhuis, Arne J.; Schulte, Shiloh A.; Brown, Stephen; Reynolds, Debra; Simons, Theodore R.

    2014-01-01

    The American Oystercatcher Haematopus palliatus is the most widely distributed of the four oystercatcher species in the Western Hemisphere. Its range covers almost the entire Atlantic Coast from northeastern United States to southern Argentina; on the Pacific Coast it is found from northern Mexico to central Chile. This assessment covers the entire range of the species, and is not intended to serve as a substitute or update for conservation plans that cover the U.S. Atlantic and Gulf Coast populations. Readers are advised to refer to those plans, available at www.whsrn.org, for more detailed information about U.S. populations.

  6. Energetics of growth in semi-precocial shorebird chicks in a warm environment : The African black oystercatcher, Haematopus moquini

    NARCIS (Netherlands)

    Tjorve, Kathleen M. C.; Underhill, Les G.; Visser, G. Henk

    2007-01-01

    We studied prefledging growth, energy expenditure and time budgets of African Black Oystercatcher, Haematopus moquini, chicks on Robben Island, Western Cape, South Africa. The aim of the study was to investigate the effect of parental feeding on the growth and energetics of semi-precocial shorebird

  7. 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.

  8. Arsenic, cadmium, chromium, lead, manganese, mercury, and selenium in feathers of Black-legged Kittiwake (Rissa tridactyla) and Black Oystercatcher (Haematopus bachmani) from Prince William Sound, Alaska

    Energy Technology Data Exchange (ETDEWEB)

    Burger, Joanna [Division of Life Sciences, Rutgers University, 604 Allison Road, Piscataway, New Jersey 08854-8082 (United States); Consortium for Risk Evaluation with Stakeholder Participation (CRESP), Piscataway, New Jersey 08854 (United States); Environmental and Occupational Health Sciences Institute (EOHSI), Piscataway, New Jersey 08854 (United States)], E-mail: burger@biology.rutgers.edu; Gochfeld, Michael [Consortium for Risk Evaluation with Stakeholder Participation (CRESP), Piscataway, New Jersey 08854 (United States); Environmental and Occupational Health Sciences Institute (EOHSI), Piscataway, New Jersey 08854 (United States); Environmental and Occupational Medicine, UMDNJ-Robert Wood Johnson Medical School, Piscataway, New Jersey 08854 (United States); Sullivan, Kelsey [U.S. Fish and Wildlife Service, 1011 East Tudor Road, Anchorage, Alaska 99503 (United States); P.O. Box 801, Bethel, Maine, 04217 (United States); Irons, David [U.S. Fish and Wildlife Service, 1011 East Tudor Road, Anchorage, Alaska 99503 (United States); McKnight, Aly [P.O. Box 801, Bethel, Maine, 04217 (United States)

    2008-07-15

    Arsenic, cadmium, chromium, lead, manganese, mercury and selenium were analyzed in the feathers of Black-legged Kittiwakes (Rissa tridactyla) from Shoup Bay in Prince William Sound, Alaska to determine if there were age-related differences in metal levels, and in Black Oystercatchers (Haematopus bachmani)) from the same region to determine if there were differences in oiled and unoiled birds. Except for mercury, there were no age-related differences in metals levels in the feathers of kittiwakes. Kittiwakes over 13 years of age had the highest levels of mercury. There were no differences in levels of metals in the feathers of oystercatchers from oiled and unoiled regions of Prince William Sound. Except for mercury, the feathers of oystercatchers had significantly higher levels of all metals than those of kittiwakes. Levels of mercury in kittiwake feathers (mean of 2910 ng/g [ppb]) were within the range of many species of seabirds reported for other studies, and were generally below adverse effects levels.

  9. Circulating fat-soluble vitamin concentrations and nutrient composition of aquatic prey eaten by American oystercatchers (Haematopus palliatus) in the southeastern United States

    Science.gov (United States)

    Carlson-Bremer, Daphne; Norton, Terry M.; Sanders, Felicia J.; Winn, Brad; Spinks, Mark D.; Glatt, Batsheva A.; Mazzaro, Lisa; Jodice, Patrick G.R.; Chen, Tai C.; Dierenfeld, Ellen S.

    2014-01-01

    The American oystercatcher (Haematopus palliatus palliatus) is currently listed as a species of high concern by the United States Shorebird Conservation Plan. Because nutritional status directly impacts overall health and reproduction of individuals and populations, adequate management of a wildlife population requires intimate knowledge of a species' diet and nutrient requirements. Fat-soluble vitamin concentrations in blood plasma obtained from American oystercatchers and proximate, vitamin, and mineral composition of various oystercatcher prey species were determined as baseline data to assess nutritional status and nutrient supply. Bird and prey species samples were collected from the Cape Romain region, South Carolina, USA, and the Altamaha River delta islands, Georgia, USA, where breeding populations appear relatively stable in recent years. Vitamin A levels in blood samples were higher than ranges reported as normal for domestic avian species, and vitamin D concentrations were lower than anticipated based on values observed in poultry. Vitamin E levels were within ranges previously reported for avian groups with broadly similar feeding niches such as herons, gulls, and terns (eg, aquatic/estuarine/marine). Prey species (oysters, mussels, clams, blood arks [Anadara ovalis], whelks [Busycon carica], false angel wings [Petricola pholadiformis]) were similar in water content to vertebrate prey, moderate to high in protein, and moderate to low in crude fat. Ash and macronutrient concentrations in prey species were high compared with requirements of carnivores or avian species. Prey items analyzed appear to meet nutritional requirements for oystercatchers, as estimated by extrapolation from domestic carnivores and poultry species; excesses, imbalances, and toxicities—particularly of minerals and fat-soluble vitamins—may warrant further investigation.

  10. Biometric sex discrimination is unreliable when sexual dimorphism varies within and between years : An example in Eurasian Oystercatchers Haematopus ostralegus

    NARCIS (Netherlands)

    van de Pol, Martijn; Oosterbeek, Kornelis; Rutten, Anne L.; Ens, B; Tinbergen, Joost M.; Verhulst, Simon

    Molecular sexing of birds has been possible for over a decade, but for practical reasons many studies still use biometric data for sex discrimination. In some species, the sexes are easy to distinguish but sexual dimorphism is often more subtle, requiring the use of statistical analyses of biometric

  11. Ecología trófica de los ostreros Haematopus palliatus pitanay (Murphy 1925 y Haematopus ater (Vieillot et Oudart 1825 en mantos del tunicado Pyura praeputialis (Heller 1878 en la Bahía de Antofagasta, Chile Trophic ecology of the oystercatchers Haematopus palliatus pitanay (Murphy 1925 and Haematopus ater (Vieillot et Oudart 1825 on beds of the tunicate Pyura praeputialis (Heller 1878 in the Bay of Antofagasta, Chile

    Directory of Open Access Journals (Sweden)

    CRISTIAN J. PACHECO

    2000-09-01

    Full Text Available En Antofagasta, norte de Chile, coexisten dos especies de ostreros: Haematopus palliatus pitanay (ostrero blanco y Haematopus ater (ostrero negro. Ambas especies depredan en un sistema rocoso intermareal peculiar cuya franja media se encuentra dominada por el tunicado Pyura praeputialis (= Pyura stolonifera bradleyi; Kott 1997. En la literatura se discute sobre las diferencias morfológicas del pico (largo y ancho entre ambos tipos de ostreros. Dichas diferencias podrían segregar los roles de forrajeo de estas aves cuando comparten un mismo hábitat: los ostreros blancos atacarían preferentemente a presas de textura "blanda" y los ostreros negros atacarían presas de textura "dura" (i.e. cobertura calcárea. En este trabajo se consideró a P. praeputialis (piure de Antofagasta como una presa de textura "blanda", ya que su tunica, compuesta por tunicina, es suave y flexible. En el estudio se comparan diversos aspectos ecológicos entre ambas especies de ostrero tales como: (a abundancia de ostreros y de otras aves costeras que depredan sobre P. praeputialis, (b distribución espacial de los ostreros en el manto de piure durante sus actividades de depredación, (c tallas de piures preferidos, (d tiempos de manipulación, (e tasa de consumo y (f frecuencia de consumo de otros invertebrados distintos del piure. Los resultados señalan a H. palliatus pitanay como la especie de ostrero que ataca con mayor frecuencia a P. praeputialis. Por otra parte, H. ater ataca con mayor frecuencia presas de textura "dura" como: lapas, caracoles, choritos, erizosAt Antofagasta, northern Chile, two oystercatcher species coexist: the white oystercatcher, Haematopus palliatus pitanay and the black oystercatcher H. ater. Both species forage on an intertidal system where the middle fringe is dominated by the tunicate Pyura praeputialis (= Pyura stolonifera bradleyi; Kott 1997. According to the literature, differences in the morphology of their bills (length and width

  12. Shellfish Fishery Severely Reduces Condition and Survival of Oystercatchers Despite Creation of Large Marine Protected Areas

    Directory of Open Access Journals (Sweden)

    Simon Verhulst

    2004-06-01

    Full Text Available Fisheries and other human activities pose a global threat to the marine environment. Marine protected areas (MPAs are an emerging tool to cope with such threats. In the Dutch Wadden Sea, large MPAs (covering 31% of all intertidal flats have been created to protect shellfish-eating birds and allow recovery of important habitats. Even though shellfish fishing is prohibited in these areas, populations of shellfish-eating birds in the Wadden Sea have declined sharply. The role of shellfish fisheries in these declines is hotly debated, therefore, we investigated the effectiveness of MPAs for protecting oystercatcher (Haematopus ostralegus populations. Shellfish stocks (cockles, Cerastoderma edule were substantially higher in the MPAs, but surprisingly this has not resulted in a redistribution of wintering oystercatchers. Oystercatchers in unprotected areas had less shellfish in their diet and lower condition (a combined measure of mass and haematological parameters, and their estimated mortality was 43% higher. It is likely, therefore, that shellfish fishing explains at least part of the 40% decline in oystercatcher numbers in recent years. Condition and mortality effects were strongest in males, and the population sex ratio was female biased, in agreement with the fact that males rely more on shellfish. The unprotected areas apparently function as an "ecological trap," because oystercatchers did not respond as anticipated to the artificial spatial heterogeneity in food supply. Consequently, the MPAs are effective on a local scale, but not on a global scale. Similar problems are likely to exist in terrestrial ecosystems, and distribution strategies of target species need to be considered when designing terrestrial and marine protected areas if they are to be effective.

  13. Seasonal changes in size selection and intake rate of Oystercatchers Haematopus ostralegus feeding on the bivalves Mytilus edulis and Cerastoderma edule

    NARCIS (Netherlands)

    Ens, B.J.; Dirksen, S; Smit, CJ; Bunskoeke, AJ

    1996-01-01

    During the course of spring, Cockles Cerastoderma edule and Mussels Mytilus edulis grow in size, while the condition, as measured by the biomass content of shells of a given size, also increases. Condition temporarily drops when the larger individuals spawn. This study investigates the effects of

  14. From sensor data to animal behaviour: an oystercatcher example.

    Directory of Open Access Journals (Sweden)

    Judy Shamoun-Baranes

    Full Text Available Animal-borne sensors enable researchers to remotely track animals, their physiological state and body movements. Accelerometers, for example, have been used in several studies to measure body movement, posture, and energy expenditure, although predominantly in marine animals. In many studies, behaviour is often inferred from expert interpretation of sensor data and not validated with direct observations of the animal. The aim of this study was to derive models that could be used to classify oystercatcher (Haematopus ostralegus behaviour based on sensor data. We measured the location, speed, and tri-axial acceleration of three oystercatchers using a flexible GPS tracking system and conducted simultaneous visual observations of the behaviour of these birds in their natural environment. We then used these data to develop three supervised classification trees of behaviour and finally applied one of the models to calculate time-activity budgets. The model based on accelerometer data developed to classify three behaviours (fly, terrestrial locomotion, and no movement was much more accurate (cross-validation error = 0.14 than the model based on GPS-speed alone (cross-validation error = 0.35. The most parsimonious acceleration model designed to classify eight behaviours could distinguish five: fly, forage, body care, stand, and sit (cross-validation error = 0.28; other behaviours that were observed, such as aggression or handling of prey, could not be distinguished. Model limitations and potential improvements are discussed. The workflow design presented in this study can facilitate model development, be adapted to a wide range of species, and together with the appropriate measurements, can foster the study of behaviour and habitat use of free living animals throughout their annual routine.

  15. From sensor data to animal behaviour: an oystercatcher example.

    Science.gov (United States)

    Shamoun-Baranes, Judy; Bom, Roeland; van Loon, E Emiel; Ens, Bruno J; Oosterbeek, Kees; Bouten, Willem

    2012-01-01

    Animal-borne sensors enable researchers to remotely track animals, their physiological state and body movements. Accelerometers, for example, have been used in several studies to measure body movement, posture, and energy expenditure, although predominantly in marine animals. In many studies, behaviour is often inferred from expert interpretation of sensor data and not validated with direct observations of the animal. The aim of this study was to derive models that could be used to classify oystercatcher (Haematopus ostralegus) behaviour based on sensor data. We measured the location, speed, and tri-axial acceleration of three oystercatchers using a flexible GPS tracking system and conducted simultaneous visual observations of the behaviour of these birds in their natural environment. We then used these data to develop three supervised classification trees of behaviour and finally applied one of the models to calculate time-activity budgets. The model based on accelerometer data developed to classify three behaviours (fly, terrestrial locomotion, and no movement) was much more accurate (cross-validation error = 0.14) than the model based on GPS-speed alone (cross-validation error = 0.35). The most parsimonious acceleration model designed to classify eight behaviours could distinguish five: fly, forage, body care, stand, and sit (cross-validation error = 0.28); other behaviours that were observed, such as aggression or handling of prey, could not be distinguished. Model limitations and potential improvements are discussed. The workflow design presented in this study can facilitate model development, be adapted to a wide range of species, and together with the appropriate measurements, can foster the study of behaviour and habitat use of free living animals throughout their annual routine.

  16. Factors affecting incubation patterns and sex roles of black oystercatchers in Alaska

    Science.gov (United States)

    Spiegel, Caleb S.; Haig, Susan M.; Goldstein, Michael I.; Huso, Manuela M. P.

    2012-01-01

    Studies examining the effects of human disturbance on avian parental behavior and reproductive success are fundamental to bird conservation. However, many such studies fail to also consider the influence of natural threats, a variable environment, and parental roles. Our work examines interactive relationships of cyclical (time of day, tide, temperature, seasonality) and stochastic (natural/human disturbance) processes with incubation patterns (attendance, bout lengths, recess rates) of the Black Oystercatcher (Haematopus bachmani), a shorebird of conservation concern. We used 24-hour-per-day video monitoring of 13 molecularly-sexed breeding pairs to systematically examine incubation, revealing previously undocumented information that may inform conservation practices for the genus. Seven of 22 video-monitored nests failed, primarily from egg depredation by nocturnally-active mammals. Analyses of 3177 hrs of video footage indicated a near doubling of incubation bout lengths at night, corresponding to the increased risk of nighttime egg predation. Females had higher overall nest attendance (54% vs. 42%) and longer mean incubation bout lengths than males (88 min vs. 73 min). Uninterrupted incubation bouts were over twice as long as bouts interrupted by disturbance. Incubating males departed nests substantially more frequently due to nest-area disturbances than females in one, but not both, years of our study. Our findings suggest that sexes exhibit different, but complimentary, incubation patterns, facilitating efficient egg care in a dynamic environment with several nest threats. We emphasize the importance of considering natural influences when evaluating human threats to shorebird reproductive behavior and success.

  17. 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.

  18. Species-environment associations and predicted distribution of Black Oystercatcher breeding pairs in Haida Gwaii, British Columbia, Canada

    Directory of Open Access Journals (Sweden)

    Sebastian Dalgarno

    2017-12-01

    Full Text Available We present a species distribution model (SDM for prediction of Black Oystercatcher (Haematopus bachmani breeding pair occurrence in Haida Gwaii, British Columbia. Boosted regression trees, a machine learning algorithm, was used to fit the model. In total, 14 predictors were selected a priori through development of a conceptual model. Breeding pair occurrence data were compiled from two available surveys conducted in 2005 and 2010 (545 km of shoreline surveyed in total. All data were aggregated to common model units (vector polyline shoreline segments approximately 100 m in length, which approximate breeding territory size. The final model, which included eight predictors (distance to treeline, island area, wave exposure, shoreline type, intertidal area within 50 m, segment length, rat occurrence, and intertidal area within 1000 m, had excellent predictive ability assessed by 10-fold cross-validation (AUC = 0.89. Predictive ability was reduced when the model was trained and tested on spatially (AUC = 0.86 and temporally (AUC = 0.83 independent data. Distance to treeline and island area had greatest influence on the model (RI = 41.5% and RI = 36.7%, respectively; we hypothesized that these predictors are related to avoidance of predators. Partial dependence plots revealed that breeding pairs tended to occur: further from the treeline, on small islands, at high wave exposures, at moderate intertidal area, on bedrock or gravel shoreline types, and on islands without rats. However, breeding pairs tended not to occur on very small islands and at very high wave exposures, which we hypothesize to reflect avoidance of nest washout. Results may inform local conservation and management efforts, i.e., from predictive maps, and eventual development of a high-resolution (~100 m model for prediction of Black Oystercatcher breeding pairs at a regional scale. Further, methods and GIS data sets developed may be used to model distribution of other coastal species

  19. FLUCTUATING SELECTION AND THE MAINTENANCE OF INDIVIDUAL AND SEX-SPECIFIC DIET SPECIALIZATION IN FREE-LIVING OYSTERCATCHERS

    NARCIS (Netherlands)

    van de Pol, Martijn; Brouwer, Lyanne; Ens, B; Oosterbeek, Kees; Tinbergen, Joost M.; Candolin, U.

    Fluctuating and disruptive selection are important mechanisms for maintaining intrapopulation trait variation. Nonetheless, few field studies quantify selection pressures over long periods and identify what causes them to fluctuate. Diet specialists in oystercatchers differ in short-term payoffs

  20. Assessment of blue mussel Mytilus edulis fisheries and waterbird shellfish-predator management in the Danish Wadden Sea

    DEFF Research Database (Denmark)

    Laursen, Karsten; Kristensen, Per Sand; Clausen, Preben

    2010-01-01

    biomass and mussel bed areas in zones closed to fishery, (ii) decrease in eiders Somateria mollissima numbers and increase or stable numbers for oystercatcher Haematopus ostralegus and herring gull Larus argentatus and (iii) that energy estimations based on ecological food requirements for the mussel-eating......We assessed the blue mussel Mytilus edulis fishery management scheme introduced in 1994 in the Danish Wadden Sea that regulate fishing vessels, fishery quota, set-aside for mussel-eating birds and established zones closed to mussel fishery. The results showed (i) a reduction in the blue mussel......, it is recommended to revise the present blue mussel management scheme in the Danish Wadden Sea, to continue and improve mussel stock and bird surveys, and to consider novel studies of the mussel-eating birds’ energetics for improved set-aside estimates and future assessments....

  1. Foot preferences during resting in wildfowl and waders.

    Science.gov (United States)

    Randler, Christoph

    2007-03-01

    Footedness in birds has been reported, e.g., in parrots and chickens, but the direction of footedness remained unclear. Is a bird left-footed because it uses its left foot for holding and handling food, or is it right-footed because it uses the right foot for stabilisation and balancing while perching? In 2004 and 2006 I examined footedness in wildfowl and waders while the birds were performing a single task: roosting on the ground on one foot. Avocet (Recurvirostra avosetta), northern shoveller (Anas clypeata), oystercatcher (Haematopus ostralegus), and Eurasian curlew (Numenius arquata) were right-footed. Another 21 species did not show any significant foot preferences. This study provides some evidence that asymmetries in preferential foot use in birds may be triggered by a preference during postural control.

  2. Profilicollis novaezelandensis n. sp. (Polymorphidae) and two other acanthocephalan parasites from shore birds (Haematopodidae and Scolopacidae) in New Zealand, with records of two species in intertidal crabs (Decapoda: Grapsidae and Ocypodidae).

    Science.gov (United States)

    Brockerhoff, A M; Smales, L R

    2002-05-01

    Profilicollis novaezelandensis n. sp. (Acanthocephala: Polymorphidae) is described from the South Island pied oystercatcher Haematopus ostralegus finschi Martens (Haematopodidae) and the intertidal crab Hemigrapsus crenulatus (Milne Edwards) (Brachyura: Grapsidae) from the South Island of New Zealand. The new species can be distinguished from all the other species of the genus by a combination of the following characters: long neck (13% of total body length for adults) and a subspherical proboscis with 14-16 longitudinal rows of 7-8 hooks. The mud crabs Helice crassa Dana (Grapsidae) and Macrophthalmus hirtipes (Heller) (Ocypodidae) were also harbouring cystacanths and the bar-tailed godwit Limosa lapponica (Linnaeus) (Scolopacidae) juveniles of P. novaezelandensis. This is the first record of brachyuran decapods as intermediate hosts of Acanthocephala from New Zealand. P. antarcticus is recorded from three crab species (Helice crassa, Hemigraspus crenulatus and Macrophthalmus hirtipes) and two bird species (Haematopus o. finschi and Limosa lapponica) in New Zealand. An unidentified species of Plagiorhynchus was also found in two bird species (H. o. finschi and H. unicolor Forster). P. antarcticus and P. novaezelandensis are the first records of Profilicollis from New Zealand.

  3. Assessment of contaminant levels and trophic relations at a World Heritage Site by measurements in a characteristic shorebird species

    Energy Technology Data Exchange (ETDEWEB)

    Schwemmer, Philipp, E-mail: schwemmer@ftz-west.uni-kiel.de [Research and Technology Centre (Forschungs- und Technologiezentrum), University of Kiel, Hafentörn 1, 25761 Büsum (Germany); Covaci, Adrian, E-mail: adrian.covaci@uantwerpen.be [Toxicological Center, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk (Belgium); Das, Krishna, E-mail: krishna.das@ulg.ac.be [Laboratory for Oceanology-MARE Research Center, University of Liege, Allée de la Chimie 17, B6C, Institut de Chimie, 4000 Liege (Sart-Tilman) (Belgium); Lepoint, Gilles, E-mail: g.lepoint@ulg.ac.be [Laboratory for Oceanology-MARE Research Center, University of Liege, Allée de la Chimie 17, B6C, Institut de Chimie, 4000 Liege (Sart-Tilman) (Belgium); Adler, Sven, E-mail: sven.adler@slu.se [Swedish University of Agricultural Sciences, 901 83 Umeå (Sweden); Garthe, Stefan, E-mail: garthe@ftz-west.uni-kiel.de [Research and Technology Centre (Forschungs- und Technologiezentrum), University of Kiel, Hafentörn 1, 25761 Büsum (Germany)

    2015-01-15

    The River Elbe is responsible for influxes of contaminants into the Wadden Sea World Heritage Site. We investigated levels of polychlorinated biphenyls (PCBs), oxychlordane (OxC), hexachlorobenzene (HCB), hexachlorocyclohexanes (α-, β-, γ-HCHs), dichlorodiphenyltrichloroethane (DDT) and its metabolites, and polybrominated diphenyl ethers (PBDEs) in blood and feathers from Eurasian oystercatchers (Haematopus ostralegus; n=28) at the Elbe and compared it with a non-riverine site about 90 km further north. (1) Mean levels of all contaminants in feathers and serum were significantly higher at the river (∑PCBs: 27.6 ng/g feather, 37.0 ng/ml serum; ∑DDTs: 5.3 ng/g feather, 4.4 ng/ml serum) compared with the non-riverine site (∑PCBs: 6.5 ng/g feather, 1.2 ng/ml serum; ∑DDTs: 1.4 ng/g feather, 0.5 ng/ml serum). Mean ∑HCH and HCB levels were <1.8 ng/g in feather and <1.8 ng/ml in serum at both sites. (2) Levels of most detectable compounds in serum and feathers were significantly related, but levels were not consistently higher in either tissue. (3) There was no significant relationship between trophic level in individual oystercatchers (expressed as δ15N) or the degree of terrestrial feeding (expressed as δ13C) and contaminant loads. (4) PBDEs were not detected in significant amounts at either site. The results of this study indicate that the outflow from one of Europe′s largest river systems is associated with significant historical contamination, reflected by the accumulation of contaminants in body tissues in a coastal benthivore predator. - Highlights: • Contaminants in Oystercatchers from the Elbe river and a non-riverine site were measured. • Mean levels of contaminants were higher at the river than at the non-riverine site. • Levels of most contaminants in serum and feathers were significantly related. • No relationship between trophic level (δ15N) and contaminant level was found. • One of Europe′s largest river systems is associated

  4. Assessment of contaminant levels and trophic relations at a World Heritage Site by measurements in a characteristic shorebird species

    International Nuclear Information System (INIS)

    Schwemmer, Philipp; Covaci, Adrian; Das, Krishna; Lepoint, Gilles; Adler, Sven; Garthe, Stefan

    2015-01-01

    The River Elbe is responsible for influxes of contaminants into the Wadden Sea World Heritage Site. We investigated levels of polychlorinated biphenyls (PCBs), oxychlordane (OxC), hexachlorobenzene (HCB), hexachlorocyclohexanes (α-, β-, γ-HCHs), dichlorodiphenyltrichloroethane (DDT) and its metabolites, and polybrominated diphenyl ethers (PBDEs) in blood and feathers from Eurasian oystercatchers (Haematopus ostralegus; n=28) at the Elbe and compared it with a non-riverine site about 90 km further north. (1) Mean levels of all contaminants in feathers and serum were significantly higher at the river (∑PCBs: 27.6 ng/g feather, 37.0 ng/ml serum; ∑DDTs: 5.3 ng/g feather, 4.4 ng/ml serum) compared with the non-riverine site (∑PCBs: 6.5 ng/g feather, 1.2 ng/ml serum; ∑DDTs: 1.4 ng/g feather, 0.5 ng/ml serum). Mean ∑HCH and HCB levels were <1.8 ng/g in feather and <1.8 ng/ml in serum at both sites. (2) Levels of most detectable compounds in serum and feathers were significantly related, but levels were not consistently higher in either tissue. (3) There was no significant relationship between trophic level in individual oystercatchers (expressed as δ15N) or the degree of terrestrial feeding (expressed as δ13C) and contaminant loads. (4) PBDEs were not detected in significant amounts at either site. The results of this study indicate that the outflow from one of Europe′s largest river systems is associated with significant historical contamination, reflected by the accumulation of contaminants in body tissues in a coastal benthivore predator. - Highlights: • Contaminants in Oystercatchers from the Elbe river and a non-riverine site were measured. • Mean levels of contaminants were higher at the river than at the non-riverine site. • Levels of most contaminants in serum and feathers were significantly related. • No relationship between trophic level (δ15N) and contaminant level was found. • One of Europe′s largest river systems is associated

  5. Individual-based ecology of coastal birds.

    Science.gov (United States)

    Stillman, Richard A; Goss-Custard, John D

    2010-08-01

    Conservation objectives for non-breeding coastal birds (shorebirds and wildfowl) are determined from their population size at coastal sites. To advise coastal managers, models must predict quantitatively the effects of environmental change on population size or the demographic rates (mortality and reproduction) that determine it. As habitat association models and depletion models are not able to do this, we developed an approach that has produced such predictions thereby enabling policy makers to make evidence-based decisions. Our conceptual framework is individual-based ecology, in which populations are viewed as having properties (e.g. size) that arise from the traits (e.g. behaviour, physiology) and interactions of their constituent individuals. The link between individuals and populations is made through individual-based models (IBMs) that follow the fitness-maximising decisions of individuals and predict population-level consequences (e.g. mortality rate) from the fates of these individuals. Our first IBM was for oystercatchers Haematopus ostralegus and accurately predicted their density-dependent mortality. Subsequently, IBMs were developed for several shorebird and wildfowl species at several European sites, and were shown to predict accurately overwinter mortality, and the foraging behaviour from which predictions are derived. They have been used to predict the effect on survival in coastal birds of sea level rise, habitat loss, wind farm development, shellfishing and human disturbance. This review emphasises the wider applicability of the approach, and identifies other systems to which it could be applied. We view the IBM approach as a very useful contribution to the general problem of how to advance ecology to the point where we can routinely make meaningful predictions of how populations respond to environmental change.

  6. Radionuclides and the birds at Ravenglass

    International Nuclear Information System (INIS)

    Lowe, V.P.W.

    1991-01-01

    Since 1983 concern has been expressed about the apparent decline in numbers of birds in the Ravenglass estuary in west Cumbria, particularly of the black-headed gull colony on the Drigg dunes, and suggestions have been made that this decline might be due to excessive radiation in the birds' food and their general environment. Twelve species of marine invertebrates from Ravenglass, known to be important foods for birds, were analysed, and further samples were taken from sites along the west Cumbrian coast. None of these samples showed excessive contamination with any of the radionuclides analysed. Analysis of a sample of bird carcasses from the area showed oystercatchers (Haematopus ostralegus) and shelduck (Tadorna tadorna) to have some of the highest concentrations of 137 Cs in their tissues; yet their breeding success and populations were not affected. Black-headed gulls were found to be feeding mainly inland, and were the least contaminated with radionuclides of all the birds at Ravenglass, yet this species and its breeding success were in decline. Calculations of the total dose equivalent rate to the whole body of the most contaminated black-headed gull amounted to 9.8 x 10 -4 mSv h -1 (∼ 8.4 x 10 -4 mGy h -1 , whole-body absorbed dose rate), and the background exposure dose was of the order of 8.3 x 10 -4 mGy h -1 . As a minimum chronic dose of 1000 mGy day -1 has been found necessary to retard growth of nestling birds, and 9600 mGy over 20 days of incubation to cause the death of 50% of embryos in black-headed gulls' eggs, the concentrations of radionuclides in the foods, body tissues and general environment were at least three orders of magnitude too low to have had any effects. (author)

  7. Environmental Assessment: Implementation of the Tyndall Air Force Base Integrated Natural Resources Management Plan

    Science.gov (United States)

    2006-04-01

    follows U.S. Highway 98. This ridge divides the Base into the Beach Dunes and Wave- Cut Bluffs physiographic region to the west and the Flatwoods Forest...wild petunia Ruellia noctiflora E Wet prairie BIRDS American oystercatcher Haematopus palliates SSC Shoreline Bald eagle Haliaeetus leucocephalus...outdoor recreation activities, including boating, canoeing, fishing, fuel wood cutting , horseback riding, hunting, and trail walking. The Base has nine

  8. Optimal control of native predators

    Science.gov (United States)

    Martin, Julien; O'Connell, Allan F.; Kendall, William L.; Runge, Michael C.; Simons, Theodore R.; Waldstein, Arielle H.; Schulte, Shiloh A.; Converse, Sarah J.; Smith, Graham W.; Pinion, Timothy; Rikard, Michael; Zipkin, Elise F.

    2010-01-01

    We apply decision theory in a structured decision-making framework to evaluate how control of raccoons (Procyon lotor), a native predator, can promote the conservation of a declining population of American Oystercatchers (Haematopus palliatus) on the Outer Banks of North Carolina. Our management objective was to maintain Oystercatcher productivity above a level deemed necessary for population recovery while minimizing raccoon removal. We evaluated several scenarios including no raccoon removal, and applied an adaptive optimization algorithm to account for parameter uncertainty. We show how adaptive optimization can be used to account for uncertainties about how raccoon control may affect Oystercatcher productivity. Adaptive management can reduce this type of uncertainty and is particularly well suited for addressing controversial management issues such as native predator control. The case study also offers several insights that may be relevant to the optimal control of other native predators. First, we found that stage-specific removal policies (e.g., yearling versus adult raccoon removals) were most efficient if the reproductive values among stage classes were very different. Second, we found that the optimal control of raccoons would result in higher Oystercatcher productivity than the minimum levels recommended for this species. Third, we found that removing more raccoons initially minimized the total number of removals necessary to meet long term management objectives. Finally, if for logistical reasons managers cannot sustain a removal program by removing a minimum number of raccoons annually, managers may run the risk of creating an ecological trap for Oystercatchers.

  9. Some observations on Seabirds breeding in the Tsitsikamma Coastal National Park.

    Directory of Open Access Journals (Sweden)

    R. J. M Crawford

    1983-12-01

    Full Text Available In 1980 and 1981 more than 50 pairs of kelp gulls Lams dominicanus, 70 of Cape cormorants Phalacrocorax capensis and 20 of whitebreasted cormorants P. carbo nested in the Tsitsikamma Coastal National Park. Kelp gulls were breeding in the Park in the mid 1960's but no records could be found of breeding by Cape cormorants prior to 1980. The earliest record for nesting by whitebreasted cormorants was 1971 and the population apparently increased in the late 1970's. Small numbers of African black oystercatchers Haematopus moquini nested in the park in 1980 and 1981. Brown mussels Perna perna and limpets Patella spp. dominated their hardshelled diet. Whereas oystercatchers at St Croix Island fed mainly on organisms from the mid intertidal region, those at Tsitsikamma appear to have favoured molluscs from the lower tidal range.

  10. The study of career decisions: Oystercatchers as social prisoners

    NARCIS (Netherlands)

    Ens, B.J.; Van de Pol, M.; Goss-Custard, J.

    2014-01-01

    To understand the social organization of species, we propose that it is necessary to unify three partial descriptions of social systems based on competition for limiting resources: adaptive distribution theory, life-history theory, and mating systems theory. Here, we illustrate what insights can be

  11. From Sensor Data to Animal Behaviour: An Oystercatcher Example

    NARCIS (Netherlands)

    Shamoun-Baranes, J.; Bom, R.; van Loon, E.E.; Ens, B.J.; Oosterbeek, K.; Bouten, W.

    2012-01-01

    Animal-borne sensors enable researchers to remotely track animals, their physiological state and body movements. Accelerometers, for example, have been used in several studies to measure body movement, posture, and energy expenditure, although predominantly in marine animals. In many studies,

  12. From sensor data to animal behaviour: an oystercatcher example

    NARCIS (Netherlands)

    Shamoun-Baranes, J.; Bom, R.; van Loon, E.E.; Ens, B.J.; Oosterbeek, K.; Bouten, W.

    2012-01-01

    Animal-borne sensors enable researchers to remotely track animals, their physiological state and body movements. Accelerometers, for example, have been used in several studies to measure body movement, posture, and energy expenditure, although predominantly in marine animals. In many studies,

  13. Status and abundance of the African Black Oystercatcher ...

    African Journals Online (AJOL)

    East London coast has more than trebled. The population increase is probably due to immigration as local breeding success is low. There are three classes of birds: breeding pairs, tenants and visitors, and birds may change status during the breeding season. In the winter, birds aggregate into groups and some birds may ...

  14. Inorganic and organic contaminants in Alaskan shorebird eggs.

    Science.gov (United States)

    Saalfeld, David T; Matz, Angela C; McCaffery, Brian J; Johnson, Oscar W; Bruner, Phil; Lanctot, Richard B

    2016-05-01

    Many shorebird populations throughout North America are thought to be declining, with potential causes attributed to habitat loss and fragmentation, reduced prey availability, increased predation, human disturbance, and increased exposure to environmental pollutants. Shorebirds may be particularly vulnerable to contaminant exposure throughout their life cycle, as they forage primarily on invertebrates in wetlands, where many contaminants accumulate disproportionately in the sediments. Therefore, it is important to document and monitor shorebird populations thought to be at risk and assess the role that environmental contaminants may have on population declines. To investigate potential threats and provide baseline data on shorebird contaminant levels in Alaskan shorebirds, contaminant concentrations were evaluated in shorebird eggs from 16 species residing in seven geographic distinct regions of Alaska. Similar to previous studies, low levels of most inorganic and organic contaminants were found, although concentrations of several inorganic and organic contaminants were higher than those of previous studies. For example, elevated strontium levels were observed in several species, especially black oystercatcher (Haematopus bachmani) sampled in Prince William Sound, Alaska. Additionally, contaminant concentrations varied among species, with significantly higher concentrations of inorganic contaminants found in eggs of pectoral sandpiper (Calidris melanotos), semipalmated sandpiper (Calidris pusilla), black oystercatcher, and bar-tailed godwit (Limosa lapponica). Similarly, significantly higher concentrations of some organic contaminants were found in the eggs of American golden plover (Pluvialis dominica), black-bellied plover (Pluvialis squatarola), pacific golden plover (Pluvialis fulva), bar-tailed godwit, and semipalmated sandpiper. Despite these elevated levels, current concentrations of contaminants in shorebird eggs suggest that breeding environments are

  15. Breeding success of Oystercatcher, terns and gulls in the Danish Wadden Sea

    DEFF Research Database (Denmark)

    Bregnballe, Thomas; Thorup, Ole; Jensen, Peter Emil

    2015-01-01

    breeding of Sandwich Terns was recorded on Langli in most of the years during 2006-2010. The Lesser Black-backed Gulls and Herring Gulls that nested on Langli were fairly successful in raising young to fledging during 2009-2013, whereas Common Gulls suffered from predation by Herring Gulls and they hardly...

  16. Spatial diversity in canopy height at Redshank and Oystercatcher nest-sites in relation to livestock grazing

    NARCIS (Netherlands)

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

    2013-01-01

    In this study we examined the effect of different livestock grazing treatments on breeding bird densities in a salt marsh habitat. To avoid an experiment on the large scale needed to directly measure grazing effects on bird densities, we followed a two-step approach. First, we measured vegetation

  17. The rate of food processing in the Oystercatcher : Food intake and energy expenditure constrained by a digestive bottleneck

    NARCIS (Netherlands)

    Kersten, M.

    1. Whether food intake is determined by the maximum rate at which animals can collect food, or by the rate at which this food can be processed, will strongly affect the organization of their behaviour. We investigated whether the digestive system imposes a constraint on (I) instantaneous rate of

  18. An evaluation of marine bird population trends following the Exxon Valdez oil spill, Prince William Sound, Alaska

    International Nuclear Information System (INIS)

    Lance, Brian K.; Irons, David B.; Kendall, Steven J.; McDonald, Lyman L.

    2001-01-01

    We examined post-spill trends (1989-1998) of marine bird populations in Prince William Sound (PWS) following the Exxon Valdez oil spill (EVOS) to evaluate recovery of injured taxa. Two criteria were employed. First, we examined population trends of injured taxa only in the oiled area of PWS using regression models. Second, we examined population trends of injured taxa in the oiled area relative to the unoiled area using homogeneity of the slopes tests. We considered a population recovering if there was a positive trend using either criteria. We considered a population not recovering if there was no trend using either criteria or a negative trend in the oiled area. A significant negative trend in the oiled area relative to the unoiled area was considered a continuing and increasing effect. Most taxa for which injury was previously demonstrated were not recovering and some taxa showed evidence of increasing effects nine years after the oil spill. Four taxa (loons Gavia spp, Harlequin Duck Histrionicus histrionicus, Bufflehead Bucephala spp, and North-western Crow Corvus caurinus) showed weak to very weak evidence of recovery. None of these taxa showed positive trends in both winter and summer. Nine taxa (grebes Podiceps spp, cormorants Phalacrocorax spp, Black Oystercatcher Haematopus bachmani, Mew Gull Larus canus, Glaucous-winged Gull Larus glaucescens, terns Sterna spp, murres Uria spp, Pigeon Guillemot Cepphus columba, and murrelets Brachyramphus spp) showed no evidence of recovery during summer or winter. Four taxa (scoters Melanitta spp, mergansers Mergus spp, goldeneyes Bucephala spp, and Black-legged Kittiwake Rissa tridactyla) showed evidence of continuing, increasing effects. We showed evidence of slow recovery, lack of recovery, and divergent population trends in many taxa which utilise shoreline and nearshore habitats where oil is likely to persist. Potential lingering spill effects and natural variability appear to be acting in concert in delaying

  19. The extending of ranges of some bird species at the north-eastern border of their distribution due to intra-century climate changes

    Directory of Open Access Journals (Sweden)

    Oleg V. Glushenkov

    2017-10-01

    emergence time of insects. Climate changes are not the only determining factors affecting the bird distribution. Ecological factors are also important, along with the mentioned above. The range expansion of species in anthropogenically disturbed landscapes occurs by means of complex chains of ecological relationships. Examples of Haematopus ostralegus and Sterna albifrons show the reasons for the reduction and restoration of species ranges due to the change in the effect of an anthropogenic factor. Thus, the range expansion of some bird species to the north and northeast is quite likely related to the centuries-old and intra-century climate changes. However, we do not consider climate warming as the only determining factor in the abundance increase and further range expanding for some birds at the range limits in temperate zone. In order to a better understanding of the impact of climate changes on birds, it is needed to investigate how modern climate changes in the temperate regions influence on the animals which serve as food for birds, and, as a consequence, how these processes impact the number of nesting pairs and the survival of young animals.

  20. Declining coastal avifauna at a diamond-mining site in Namibia ...

    African Journals Online (AJOL)

    A review of Namibian shorebird densities over two decades and two additional visits to the coastal diamond-mining areas at Elizabeth Bay, southern Namibia, were undertaken to assess the long-term influence of mining activity on density of shorebirds (Charadrii) and particularly threatened African Black Oystercatchers ...

  1. Phenotypic and genotypic characters of isolates of Pasteurella multocida obtained from back-yard poultry and from two outbreaks of avian cholera in avifauna in Denmark

    DEFF Research Database (Denmark)

    Christensen, J.P.; Dietz, Hans-Henrik; Bisgaard, M.

    1998-01-01

    Two outbreaks of fowl cholera in the avifauna in Denmark, affecting primarily elders but also cormorants, gulls and oyster-catchers were shown to be caused by the same clone of Pasteurella multocida ssp, multocida by restriction enzyme analysis (REA) and ribotyping, using the enzymes HpaII and Hha...

  2. Differential reactions to anthropogenic disturbance by two ground ...

    African Journals Online (AJOL)

    Both ABO and KG significantly altered their behavioural responses to disturbance from pre-breeding to breeding. These results emphasise the need to have a buffer zone surrounding breeding areas excluding human presence to allow for the successful breeding of ABO. Keywords: African Black Oystercatcher, buffer zone, ...

  3. Nieuwe ontdekkingen en mogelijkheden in het onderzoek aan Scholeksters dankzij het UvA Bird Tracking Systeem

    NARCIS (Netherlands)

    Ens, B. J.; Bom, R. A.; Dokter, A. M.; Oosterbeek, K.; de Jong, Jan; Bouten, W.

    2014-01-01

    This paper reports on new discoveries and new possibilities due to the deployment of the UvA Bird Tracking System (UvA-BiTS; Bouten et al. 2013) in our investigations of the behavioural ecology of Oystercatchers. This GPS tracker is powered by solar cells and not only stores GPS locations, but also

  4. Environmental Assessment for Construction of a Multi-Story Dormitory at Tyndall Air Force Base, Florida

    Science.gov (United States)

    2006-11-01

    ionantha T E Cypress domes White-flowered wild petunia Ruellia noctiflora E Wet prairie BIRDS American oystercatcher...The parking and street lights will be full cut fixtures in addition to being fully s hielded and using low pressure sodium lamps .. 2 ) The height...uction Ms .. Patrick, Thank you for the rapid response to our letter. Below are tbe r .esponses to your comments: 1 . The light wi l l be ful l cut

  5. Parasitism of Ground Beetles (Coleoptera: Carabidae) by a New Species of Hairworm (Nematomorpha: Gordiida) in Arctic Canada.

    Science.gov (United States)

    Ernst, Crystal M; Hanelt, Ben; Buddle, Christopher M

    2016-06-01

    The host-parasite associations between ground beetles (Coleoptera: Carabidae) and hairworms (Nematomorpha: Gordiida) collected from the Arctic (an understudied and ecologically important region) is described. Carabids and their parasites were collected from 12 sites spanning the 3 northernmost ecoclimatic zones of Canada (north boreal, subarctic, and high Arctic) using standardized methods. The beetles and hairworms were identified using traditional morphological approaches. Seven beetle species are recorded as hosts: Amara alpina, Pterostichus caribou, Pterostichus brevicornis, Pterostichus tareumiut, Pterostichus haematopus, Patrobus septentrionis, and Notiophilus borealis. All represent new host records (increasing the known North American host list from 14 to 21), and this is the first record of hairworm infection in the genus Notiophilus. Beetles from Banks Island, Northwest Territory, were infected in high numbers (11-19% per sampling period) and were used as an ecological case study. There was no significant relationship between infection status and host species, body size, or sex. Beetles collected in yellow pan traps and in wet habitats were more likely to be infected, likely due to water-seeking behavior induced by the parasites. Morphological examinations indicate that the hairworms collected from all locations represent a single, new species of Gordionus, making it only the sixth hairworm species and the third species of that genus found in Canada. Hosts are unknown for all other Canadian (and 1 Alaskan) Gordionus species.

  6. Economic valuation of mangrove ecosystem: empirical studies in Timbulsloko Village, Sayung, Demak, Indonesia

    Science.gov (United States)

    Perdana, T. A.; Suprijanto, J.; Pribadi, R.; Collet, C. R.; Bailly, D.

    2018-03-01

    Ecosystem resilience is the capacity of ecosystems to tolerate disorders without collapsing into different circumstances qualitatively controlled by a different set of processes. A robust ecosystem is one that can withstand shocks and rebuild itself when necessary. This study aims to identify the value of use-based economy and non-use value of current economy; calculating the total economic value of mangrove resources; and provide suggestions and recommendations based on observations in Timbulsloko, Sayung, Demak. The method used is economic valuation with total economic value technique. The sampling technique used non-probability and purposive sampling method. The results showed that the direct use value of mangroves was utilized by fisherman, fish pond farmers, branjang catchers, oystercatchers, trap makers, shop owner, grilled fish makers and shrimp chip makers. Indirect use value was derived from function as the breakwater, beach belt and hybrid engineering. Existing value was not less than 10 % of the direct use value. The total economic value was Rp. 6,361,430,639/year or about Rp. 202,335,580.1/ha/year. It is need to improve the community awareness to mangrove ecosystem and to the role of breakwater in order to reduce risk disaster and to develop an ecotourism in the area.

  7. Climate change impacts on potential recruitment in an ecosystem engineer.

    Science.gov (United States)

    Morgan, Emer; O' Riordan, Ruth M; Culloty, Sarah C

    2013-03-01

    Climate variability and the rapid warming of seas undoubtedly have huge ramifications for biological processes such as reproduction. As such, gametogenesis and spawning were investigated at two sites over 200 km apart on the south coast of Ireland in an ecosystem engineer, the common cockle, Cerastoderma edule. Both sites are classed as Special Areas of Conservation (SACs), but are of different water quality. Cerastoderma edule plays a significant biological role by recycling nutrients and affecting sediment structure, with impacts upon assemblage biomass and functional diversity. It plays a key role in food webs, being a common foodstuff for a number of marine birds including the oystercatcher. Both before and during the study (early 2010-mid 2011), Ireland experienced its two coldest winters for 50 years. As the research demonstrated only slight variation in the spawning period between sites, despite site differences in water and environmental quality, temperature and variable climatic conditions were the dominant factor controlling gametogenesis. The most significant finding was that the spawning period in the cockle extended over a greater number of months compared with previous studies and that gametogenesis commenced over winter rather than in spring. Extremely cold winters may impact on the cockle by accelerating and extending the onset and development of gametogenesis. Whether this impact is positive or negative would depend on the associated events occurring on which the cockle depends, that is, presence of primary producers and spring blooms, which would facilitate conversion of this extended gametogenesis into successful recruitment.

  8. Radionuclide concentrations in bird tissues, their foods and feeding areas near Ravenglass

    International Nuclear Information System (INIS)

    Lowe, V.P.W.

    1987-08-01

    Since 1983, concern has been expressed about an apparent decline in the numbers of waterfowl, waders and gulls in the Ravenglass estuary, particularly of the black-headed gulls nesting on the Drigg dunes; it was suggested this might be due to the radionuclide concentrations in their diet and general environment. Oystercatchers and shelduck had some of the highest concentrations of Cs-137 in their tissues, yet their breeding and numbers remained unaffected. Calculations of the total dose equivalent to the whole body of gulls spending 4 months in the estuary before laying eggs, amounted to 2.8 mSv (≅ 2.4 m Gy), and to the gut lining 40.3 mSv. As a minimum chronic dose of 1000 m Gy d -1 has been found to be necessary to retard the growth of chicks or cause 50% mortality among gull chick embryos before full development, radionuclide concentrations at Ravenglass were at least three orders of magnitude too low to have any effect. 12 species of marine invertebrates were also analysed, but no evidence was found that radionuclides from Sellafield were being accumulated in any species to the point where concentrations were of potential importance to birds feeding on them. (author)

  9. Exxon Valdez Oil Spill Restoration Project final report: Monitoring for evaluation of recovery and restoration of injured nearshore resources

    Science.gov (United States)

    Ballachey, Brenda E.; Bodkin, James L.; Kloecker, Kim; Dean, Tom; Colettie, Heather A

    2015-01-01

    In 2012, we completed three consecutive years of full field sampling in WPWS for EVOS Restoration Project 10100750. Nearshore monitoring was conducted in collaboration with the NPS SWAN I&M program and, beginning in 2012, as part of the EVOSTC GWA program. Data collection was done in accordance with standard operating procedures set forth to monitor marine water chemistry and quality, marine intertidal invertebrates, kelps and seagrasses, marine birds, black oystercatchers, and sea otters. Summer sampling in 2012 represented the fourth year of sampling in WPWS (an initial year of sampling was done in WPWS in 2007; EVOS Restoration Project 070750). Based on our monitoring of nearshore species in WPWS, and comparisons of data from WPWS and other areas within the Gulf of Alaska, we have no evidence of continued injury to biological resources at the spatial scales we are monitoring. A key finding is that recovery of the sea otter population is no longer constrained by exposure to lingering oil; this is consistent with related EVOSTC studies on harlequin ducks (Restoration Project 12120114-Q). We anticipate continued annual nearshore monitoring in WPWS and at KATM and KEFJ under GWA, with data summaries and analyses including all three areas to provide a larger spatial and temporal context to the understanding of processes and patterns in nearshore ecosystems of the GOA which were impacted by the EVOS of 1989.

  10. Presencia y abundancia de aves que se reproducen en islas de la bahía de Mazatlán, Sinaloa, México

    Directory of Open Access Journals (Sweden)

    Alberto Piña-Ortiz

    2017-04-01

    Full Text Available Registramos la presencia y abundancia de aves, así como el hábitat y temporalidad de la reproducción de especies en las islas Pájaros, Venados, Lobos, Hermano Norte y Hermano Sur, ubicadas en la bahía de Mazatlán. Realizamos siete recorridos entre noviembre de 2014 y mayo de 2015; además contábamos con información colectada en mayo de 2004. Observamos un total de 59 especies de aves, de las cuales 15 fueron reproductoras: Dendrocygna autumnalis (pijije ala blanca, Phaethon aethereus (rabijunco pico rojo, Sula leucogaster (bobo café, Pelecanus occidentalis (pelícano café, Ardea herodias (garza morena, Ardea alba (garza blanca, Egretta thula (garza pie dorado, Bubulcus ibis (garza ganadera, Nycticorax nycticorax (pedrete corona negra, Nyctanassa violacea (pedrete corona clara, Eudocimus albus (ibis blanco, Coragyps atratus (zopilote común, Haematopus palliatus (ostrero americano, Larus heermanni (gaviota ploma y Falco peregrinus (halcón peregrino. Para P. aethereus y S. leucogaster no había reportes previos de reproducción en estas islas; además, confirmamos la anidación de L. hermanni. La isla Pájaros fue la que albergó el mayor número de especies reproductoras (10 especies. Pelecanus occidentalis fue la especie más abundante con un total de 1 559 individuos, seguido de Fregata magnificens (fragata magnífica y Sula nebouxii (bobo pata azul con 1 526 y 1 100 individuos, respectivamente; aunque para estas dos últimas especies no hubo registros de reproducción. Las islas se encuentran bajo protección, pero se requiere realizar monitoreos para establecer el estado y tendencias de las poblaciones de aves, así como los efectos de las perturbaciones por actividades humanas y por las especies introducidas.

  11. Hematological indices of injury to lightly oiled birds from the Deepwater Horizon oil spill

    Science.gov (United States)

    Fallon, Jesse A.; Smith, Eric P.; Schoch, Nina; Paruk, James D.; Adams, Evan A.; Evers, David C.; Jodice, Patrick G. R.; Perkins, Christopher; Schulte, Shiloh A.; Hopkins, William A.

    2018-01-01

    Avian mortality events are common following large‐scale oil spills. However, the sublethal effects of oil on birds exposed to light external oiling are not clearly understood. We found that American oystercatchers (area of potential impact n = 42, reference n = 21), black skimmers (area of potential impact n = 121, reference n = 88), brown pelicans (area of potential impact n = 91, reference n = 48), and great egrets (area of potential impact n = 57, reference n = 47) captured between 20 June 2010 and 23 February 2011 following the Deepwater Horizon oil spill experienced oxidative injury to erythrocytes, had decreased volume of circulating erythrocytes, and showed evidence of a regenerative hematological response in the form of increased reticulocytes compared with reference populations. Erythrocytic inclusions consistent with Heinz bodies were present almost exclusively in birds from sites impacted with oil, a finding pathognomonic for oxidative injury to erythrocytes. Average packed cell volumes were 4 to 19% lower and average reticulocyte counts were 27 to 40% higher in birds with visible external oil than birds from reference sites. These findings provide evidence that small amounts of external oil exposure are associated with hemolytic anemia. Furthermore, we found that some birds captured from the area impacted by the spill but with no visible oiling also had erythrocytic inclusion bodies, increased reticulocytes, and reduced packed cell volumes when compared with birds from reference sites. Thus, birds suffered hematologic injury despite no visible oil at the time of capture. Together, these findings suggest that adverse effects of oil spills on birds may be more widespread than estimates based on avian mortality or severe visible oiling.

  12. Avian Field guide and checklist for Kunsan Air Base, Korea.

    Energy Technology Data Exchange (ETDEWEB)

    Levenson, J. B.; Environmental Assessment

    2005-11-15

    This report summarizes the results of the avian surveys conducted at Kunsan Air Base (AB). This on-going survey is conducted to comply with requirements of the Environmental Governing Standards (EGS) for the Republic of Korea, the Integrated Natural Resources Management Plan (INRMP) for Kunsan AB, and the 8th Fighter Wing's Bird Aircraft Strike Hazard (BASH) Plan. One hundred sixteen bird species representing 34 families were identified and recorded. Seven species are designated as Cultural Property Monuments, and their protection is accorded by the Korean Ministry of Culture and Tourism. Six species appear on the Korean Association for Conservation of Nature's(KACN's) list of Reserved Wild Species and are protected by the Korean Ministry of Environment. Combined, only ten different species are Republic of Korea (ROK)-protected because the Eurasian Spoonbill, Peregrine Falcon, and Eurasian Oystercatcher are listed by both agencies. The primary objective of the avian survey at Kunsan AB was to determine what species of birds are present on the airfield and their respective habitat requirements during the critical seasons of the year. This requirement is specified in Annex C.4.a.(1-4) of the 8th Fighter Wing BASH Plan(8FWOPLAN 91-202). The second objective was to initiate surveys to determine what bird species are present on Kunsan AB throughout the year, and from the survey results determine if threatened, endangered, or other Korean-listed bird species are present on Kunsan AB. This overall census satisfies Criterion 13-3.e of the EGS for Korea. The final objective was to formulate management strategies within Kunsan AB's operational requirements to protect and enhance habitats of known threatened, endangered, and ROK-protected species in accordance with EGS Criterion 13-3.a and also that are favorable for the reproduction of indigenous species in accordance with the EGS Criterion 13-3.h.

  13. Variación temporal de la población de la almeja Darina solenoides y del mejillón Mytilus Edulis Platensis, y su relación con la alimentación del ostrero austral

    Directory of Open Access Journals (Sweden)

    Lorenzo Javier Gallardo

    2014-06-01

    Full Text Available Resumen. El presente trabajo de investigación se ha planteado en el marco de una beca para alumnos avanzados de la UNPA, Unidad Académica Río Gallegos. Tiene como objetivo analizar las variaciones temporales de la población del mejillón Mytilus edulis platensis y de la almeja Darina solenoides y se inserta en un Proyecto de Investigación (29A/227 dirigido por Dra. Z. Lizarralde que tiene como objeto estudiar la ecología trófica del Ostrero Austral (Haematopus leucopodus en el estuario del río Gallegos (Santa Cruz. Durante el 2010 se efectuaron muestreos mensuales (abril a diciembre en un banco de mejillones y otro de almejas, con el objeto de analizar la variación temporal de la densidad y biomasa, y la estructura de tallas poblacional. Se analizó la granulometría y porcentaje de materia orgánica de los sedimentos. El sedimento del banco de mejillones se encuentra constituido en su mayoría por la fracción correspondiente a los gránulos; en el banco de almejas por arenas muy finas (43% y finas (39%. En ambos casos la materia orgánica no supera el 3 %. La densidad de mejillones alcanzó un valor máximo de 2255 individuos/m2 en abril y un mínimo de 497 en noviembre. La biomasa máxima se encontró en abril (110 g/m 2. La densidad de Darina solenoides alcanzó un valor máximo de 565 en junio y un mínimo de 282 individuos/m2 en el mes de octubre. La biomasa máxima ocurrió en diciembre (132 g/m2. No se detectó el período de reclutamiento de nuevos individuos en los bancos de las especies estudiadas.

  14. The possible hindrance of a 25 MW wind farm for birds at two potential sites in Noord-Groningen: Annex

    International Nuclear Information System (INIS)

    Van den Bergh, L.M.J.; Spaans, A.L.

    1994-01-01

    In this appendix to an earlier published report the possible impact of a planned wind farm of 110 33M-VS wind turbines on birds in north Groningen is assessed, and the results with the estimates made for two alternative locations in that region are estimated. The new location (Emmapolder and Eemspolder/Eemshaven) combines parts of the two locations studied earlier. It has been calculated that in the new location 701 birds per year will certainly or probably collide with a wind turbine, and 945 birds certainly, probably or possibly. If 83 wind turbines are built (as planned for the two alternative locations mentioned) these figures will be 541 and 723, respectively. It is estimated that maximally 2,000-3,000 (110 wind turbines) and 1,500-2,000 birds (83 wind turbines) will be killed in the area per year. The numbers of bird disturbed are estimated at a few thousands for all species combined with greatest values for Curlew and Oystercatcher. If a wind park will be chosen with 83 wind turbines (taking out 27 wind turbines in the western portion of the wind park) the figure amounts to 1,000-2,000. The study reveals that the impact of a 25 MW wind park (83 wind turbines) in northern Groningen is smallest when it is built either in the Eemshaven/Delfzijl area or in the Emma- and Eemspolder/Eemshaven area. The impact is greatest when the wind park is concentrated in the Emma- and Eemspolder. The impact of a wind park with 110 wind turbines in the Emma- and Eemspolder/Eemshaven area is (1) larger than the impact of a wind park with 83 wind turbines in the Emma- and Eemspolder as far as the disturbance of passing birds (seasonal migration, local bird movements) is concerned, (2) roughly as large as the impact of such a park in these polders as far as the number of collision victims is concerned, and (3) in-between the impact of the two other locations as far as the disturbance of feeding and resting birds is concerned