Canaris, Albert G; Ortiz, Rafael; Canaris, Gay J
Eighty-eight long-billed dowitchers, Limnodromus scolopaceus, were examined for helminth parasites, 62 from Texas and 26 from Mexico. In total, 3,558 helminth parasites were obtained from this host, 2,273 from Texas birds and 1,285 from birds from Mexico. The component communities consisted of 22 species of helminths in Texas, and 19 in Mexico. Of a total of 26 helminth species recorded from the 2 localities, 15 were common to both, 7 found only in Texas, and 4 only in Mexico. Fifty-nine of 62 Texas birds and 25 of 26 birds from Mexico were infected. The most prevalent helminth for Texas was the cestode Shipleya inermis. The cestode Aploparaksis retroversa was the most abundant, accounting for 37% of the total abundance, and was second highest in prevalence. Five species of cestodes, A. retroversa, Aploparaksis diagonalis, Aploparaksis occidentalis, Aploparaksis rissae, and Shipleya inermis accounted for 79% of total abundance. In the sample from Mexico, S. inermis was also highest in prevalence, followed by the nematode Hystrichis tricolor. The cestode A. retroversa was highest in abundance at 50% of the total, and was third highest in prevalence. Mean species richness, diversity, and evenness were similar among the component communities of Texas and Mexico. A predictable suite of aploparaksid cestodes, together with the cestode S. inermis, constituted 79%, and 61%, of total abundance for the component communities of Texas and Mexico, respectively, and were present in all component communities for locality, season, and year. The cestodes, A. retroversa and S. inermis, were the dominant species in all component communities. Differences among component communities and low similarities for all other comparisons were largely caused by less predictable suites of helminth species. A checklist of helminth parasites reported for long-billed dowitchers is included.
Schroeder, S.C.; Reed, D.C.; Kushner, D.J.; Estes, J.A.; Ono, D.S.
In this paper we describe an instance of unusual, agonistic behavior in a flock of migrant Short-billed Dowitchers (Limnodromus griseus) . We compare this behavior to that of other flocks feeding at the same time at other locations in the same estuary and then present evidence suggesting that this behavior resulted from the patchy distribution of the probable foraging resource of this flock, eggs of the horseshoe crab (Limulus polyphemus). We propose that an extremely patchy resource has increased the agonistic behavior within the flock by increasing the variation in foraging success among individuals.
Williams, Joseph B.; Tieleman, B. Irene; Visser, G. Henk; Ricklefs, Robert E.
We measured resting and peak metabolic rates (RMR and PMR, respectively) during development of chicks of seven species of shorebirds: least sandpiper (Calidris minutilla; adult mass 20 22 g), dunlin (Calidris alpina; 56-62 g), lesser yellowlegs (Tringa flavipes; 88-92 g), short-billed dowitcher
Saalfeld, Sarah T.; Lanctot, Richard B.; Brown, Stephen C.; Saalfeld, David T.; Johnson, James A.; Andres, Brad A.; Bart, Jonathan R.
The Arctic Coastal Plain (ACP) of Alaska is an important region for millions of migrating and nesting shorebirds. However, this region is threatened by climate change and increased human development (e.g., oil and gas production) that have the potential to greatly impact shorebird populations and breeding habitat in the near future. Because historic data on shorebird distributions in the ACP are very coarse and incomplete, we sought to develop detailed, contemporary distribution maps so that the potential impacts of climate-mediated changes and development could be ascertained. To do this, we developed and mapped habitat suitability indices for eight species of shorebirds (Black-bellied Plover [Pluvialis squatarola], American Golden-Plover [Pluvialis dominica], Semipalmated Sandpiper [Calidris pusilla], Pectoral Sandpiper [Calidris melanotos], Dunlin [Calidris alpina], Long-billed Dowitcher [Limnodromus scolopaceus], Red-necked Phalarope [Phalaropus lobatus], and Red Phalarope [Phalaropus fulicarius]) that commonly breed within the ACP of Alaska. These habitat suitability models were based on 767 plots surveyed during nine years between 1998 and 2008 (surveys were not conducted in 2003 and 2005), using single-visit rapid area searches during territory establishment and incubation (8 June, 1 July). Species specific habitat suitability indices were developed and mapped using presence-only modeling techniques (partitioned Mahalanobis distance) and landscape environmental variables. For most species, habitat suitability was greater at lower elevations (i.e., near the coast and river deltas) and lower within upland habitats. Accuracy of models was high for all species, ranging from 65 -98%. Our models predicted that the largest fraction of suitable habitat for the majority of species occurred within the National Petroleum Reserve-Alaska, with highly suitable habitat also occurring within coastal areas of the Arctic National Wildlife Refuge west to Prudhoe Bay.
organisms by blanketing stream or lake bottoms, spawning beds, or other desirable bottom area. Suspended solids may kill fish and shellfish by causing...Tree S~rv Long-billed M~arsh Wren 0Ctlipping S;-arrcd Short-billed Marsh Wren N Clay-crod )rm: Mockingbird L. Field Sparrow Gray Catbird VH;;rris
Distribución espacio-temporal de aves acuáticas invernantes en la Ciénega de Tláhuac, planicie lacustre de Chalco, México Spatio-temporal distribution of wintering aquatic birds in the Ciénega de Tláhuac, Chalco lacustrine plain, Mexico
Full Text Available La avifauna acuática invernal de la ciénaga de Tláhuac fue estudiada de noviembre de 2006 a febrero de 2007; se identificaron 40 especies, 3 de las cuales corresponden a nuevos registros. El área fue utilizada por, al menos, 25 000 aves acuáticas; 5 fueron las especies dominantes: 3 anátidos (Anas clypeata, A. platyrhynchos diazi y Oxyura jamaicensis, 1 ave playera (Limnodromus scolopaceus y 1 gallareta (Fulica americana. Sobresalió por su abundancia A. platyrhynchos diazi, subespecie endémica y amenazada, ya que los 2 200 individuos observados representan el 4% de la población total estimada. Las especies mejor representadas mostraron una utilización espacial diferencial, con 3 patrones: 1 especies con distribución uniforme (A. clypeata y F. americana, 2 las agrupadas en una sola porción del humedal (A.p. diazi y O. jamaicensis y 3 aquella con afinidad por 2 porciones del humedal (L. scolopaceus. La ciénega de Tláhuac es un humedal importante para la avifauna de la región; en ella ocurren, durante el invierno, 6 especies protegidas por el gobierno mexicano; sin embargo, existen factores antrópicos que ponen en riesgo su integridad y que hacen necesarias acciones de protección y conservación.The winter waterbirds of the Ciénega de Tláhuac were studied from November 2006 to February 2007; a total of 40 species were observed, with 3 new records. The area was usedby al least 25 000 birds; 5 species were the dominant: 3 anatids (Anas clypeata, A. platyrhynchos diazi y Oxyura jamaicensis, 1 shorebird (Limnodromus scolopaceus and 1 coot (Fulica americana. The abundance of A. platyrhynchos diazi, a threatened endemic subspecies, was remarkable because the 2 200 individuals observed represent 4% of its population.The best represented species showed a differential spatial use, with 3 patterns: 1 species with homogeneous use (A. clypeata y F. americana, 2 with affinity to a single portion of the wetland (A. p. diazi y O. jamaicensis
Dickson, D L; Dickson, H L; Aiudi, G M
The distribution, abundance, and habitat preferences of birds were studied at Stokes Point, Phillips Bay and King Point in the northern Yukon in 1983. These data were gathered to assist in decisions about future development of a port to support marine drilling activities in the Beaufort Sea. Nesting bird densities at Stokes Point were similar to those found elsewhere on the Yukon Coastal Plain due to the similarity in habitat. The lagoon at Stokes Point was locally important to molting ducks. Several species occurred in higher densities at Phillips Bay than elsewhere on the Plain, mainly due to the deltas and spits created by rivers flowing into the Bay. These deltas were locally important to such species as molting non-breeding tundra swans, Canada geese, and ducks. During ground surveys in June, habitat was classified into 13 types and the nesting density for each bird species calculated for each habitat type. Overall bird densities were more than 3 times higher in lowland than in upland habitats. Passerine densities and species were highest in the tall shrub type of habitat found primarily in stream and river valleys. The Yukon Coastal Plain is an important nesting area for the stilt sandpiper, which has a limited breeding range. The Plain is also nationally important for nesting long-billed dowitchers and yellow wagtails, both fairly common in the study area but with very limited breeding distribution within Canada. The Plain is also internationally important to fall staging snow geese. 38 refs., 17 figs., 35 tabs.
Full Text Available Billfishes area by cacth of tuna long line vessels in Indian Ocean. Billfish are consist of swordfish Xiphias gladius, black marlin Makaira indica, indo facific blue marlin Makaira mazara, stripe marlin Tetrapturus audax, indo facific sailfish Istiophorus platypterus and shortbill spearfish Tetrapturus angustirostris. Besides that, billfishes also have important economic value compared with tuna as an exsported species such as swordfish and marlin. To optimize the catch of billfishes in Indian Ocean, data and information of potential fishing ground, size and catch composition of this species are needed. The billfishes cacth composition collected in 2011 were dominated by 45% swordfish, 20% black marlin, 19% blue marlin,9% short bill spearfish, 6% sailfish and 1%stripe marlin. The billfishes size range which were caught between 60 - 280 cm LJFL (Lower Jaw Fork Length. The sword fish average length was 150 cm, blue marlin 197 cm, black Marlin 189 cm, sailfish 150cm ,short bill spearfish 144 cm and stripe marlin159 cm. From this observation, it was found that most of billfishes caught were in mature.
Maglianesi, María A; Böhning-Gaese, Katrin; Schleuning, Matthias
In plant-pollinator networks, the floral morphology of food plants is an important determinant of the interaction niche of pollinators. Studies on foraging preferences of pollinators combining experimental and observational approaches may help to understand the mechanisms behind patterns of interactions and niche partitioning within pollinator communities. In this study, we tested whether morphological floral traits were associated with foraging preferences of hummingbirds for artificial and natural flower types in Costa Rica. We performed field experiments with artificial feeders, differing in length and curvature of flower types, to quantify the hummingbirds' interaction niche under unlimited nectar resources. To quantify the interaction niche under real-world conditions of limited nectar resources, we measured foraging preferences of hummingbirds for a total of 34 plant species. Artificial feeders were visited by Eupherusa nigriventris and Phaethornis guy in the pre-montane forest, and Lampornis calolaemus in the lower montane forest. Under experimental conditions, all three hummingbird species overlapped their interaction niches and showed a preference for the short artificial flower type over the long-straight and the long-curved flower types. Under natural conditions, the two co-occurring hummingbird species preferred to feed on plant species with floral traits corresponding to their bill morphology. The short-billed hummingbird E. nigriventris preferred to feed on short and straight flowers, whereas the long- and curved-billed P. guy preferred long and curved natural flowers. The medium-size billed species L. calolaemus preferred to feed on flowers of medium length and did not show preferences for plant species with specific corolla curvature. Our results show that floral morphological traits constrain access by short-billed hummingbird species to nectar resources. Morphological constraints, therefore, represent one important mechanism structuring trophic
Full Text Available Urbanization is a widespread and rapidly growing threat to biodiversity, therefore we need a predictive understanding of its effects on species and ecosystem processes. In this paper we study the impact of urbanization on a guild of nectar-feeding birds in a biodiversity hotspot at the Cape of Africa. The guild of four bird species provides important ecosystem services by pollinating 320 plant species in the Cape Floral Region. Functional diversity within the guild is related to differences in bill length. The long-billed Malachite Sunbird (Nectarinia famosa plays an irreplaceable role as the exclusive pollinator of plant species with long nectar tubes. We analyzed the composition of the guild in suburban gardens of Cape Town along a gradient of increasing distance from the nearest natural habitat. Urbanization reduces the functional diversity of the nectarivore guild. Malachite Sunbirds did not penetrate more than 1 km into the city, whereas only the short-billed Southern Double-collared Sunbirds (Cinnyris chalybea occurred throughout the urbanization gradient. The lack of data precludes conclusions regarding the detailed responses of Orange-breasted Sunbirds (Anthobaphes violacea and Sugarbirds (Promerops cafer, however their absence across the entire gradient is suggestive of high sensitivity. The functional diversity of this guild of pollinators can potentially be restored, but the pros and cons of this conservation action need to be considered.
Potier, Simon; Duriez, Olivier; Cunningham, Gregory B; Bonhomme, Vincent; O'Rourke, Colleen; Fernández-Juricic, Esteban; Bonadonna, Francesco
Birds, particularly raptors, are believed to forage primarily using visual cues. However, raptor foraging tactics are highly diverse - from chasing mobile prey to scavenging - which may reflect adaptations of their visual systems. To investigate this, we studied the visual field configuration of 15 species of diurnal Accipitriformes that differ in such tactics, first focusing on the binocular field and blind area by using a single traits approach, and then exploring the shape of the binocular field with morphometric approaches. While the maximum binocular field width did not differ in species of different foraging tactics, the overall shape of their binocular fields did. In particular, raptors chasing terrestrial prey (ground predators) had a more protruding binocular field and a wider blind area above the head than did raptors chasing aerial or aquatic prey and obligate scavengers. Ground predators that forage on mammals from above have a wide but short bill - which increases ingestion rate - and large suborbital ridge to avoid sun glare. This may explain the protruding binocular field and the wide blind area above the head. By contrast, species from the two other groups have long but narrow bills used to pluck, flake or tear food and may need large visual coverage (and reduced suborbital ridges) to increase their foraging efficiency ( e.g. using large visual coverage to follow the escaping prey in three dimensions or detect conspecifics). We propose that binocular field shape is associated with bill and suborbital ridge shape and, ultimately, foraging strategies. © 2018. Published by The Company of Biologists Ltd.
Temeles, Ethan J; Miller, Jill S; Rifkin, Joanna L
Unambiguous examples of ecological causation of sexual dimorphism are rare, and the best evidence involves sexual differences in trophic morphology. We show that moderate female-biased sexual dimorphism in bill curvature is the ancestral condition in hermit hummingbirds (Phaethornithinae), and that it is greatly amplified in species such as Glaucis hirsutus and Phaethornis guy, where bills of females are 60 per cent more curved than bills of males. In contrast, bill curvature dimorphism is lost or reduced in a lineage of short-billed hermit species and in specialist Eutoxeres sicklebill hermits. In the hermits, males tend to be larger than females in the majority of species, although size dimorphism is typically small. Consistent with earlier studies of hummingbird feeding performance, both raw regressions of traits and phylogenetic independent contrasts supported the prediction that dimorphism in bill curvature of hermits is associated with longer bills. Some evidence indicates that differences between sexes of hermit hummingbirds are associated with differences in the use of food plants. We suggest that some hermit hummingbirds provide model organisms for studies of ecological causation of sexual dimorphism because their sexual dimorphism in bill curvature provides a diagnostic clue for the food plants that need to be monitored for studies of sexual differences in resource use.
Sagong, Woong; Jeon, Woo-Pyung; Choi, Haecheon
The sailfish and swordfish are known as fastest sea animals, reaching their maximum speeds of more than 100km/h. Recently, Sagong et al. (2008, Phys. Fluids) investigated the role of V- shaped protrusions existing on the sailfish skin in the skin-friction reduction but those protrusions did not make a direct role in reducing drag. On the other hand, the long bill has been regarded as a device of reducing drag by separation delay through turbulence generation. In the present study, we investigate the hydrodynamic characteristics of sailfish and swordfish by installing the stuffed ones in a wind tunnel and measuring the drag on their bodies and boundary-layer velocities above the body surfaces. The drag coefficients of sailfish and swordfish are 0.0075 and 0.009 based on the free-stream velocity and wetted area, respectively. They are comparable to or smaller than those of other kinds of fish such as the dogfish, tuna and trout. Next, the role of bill on the drag is studied. The drag without bill or with an artificial short bill is lower than that with the original long bill, indicating that the bill does not reduce the drag at all. From the velocity measurement near the body surfaces, we found that flow separation does not occur even without bill, and thus the conjecture that the flow separation is delayed through turbulence generation by the bill is not valid.
Luciana B. Mendonça
Full Text Available We investigated flower morphology, nectar features, and hummingbird visitation to Palicourea crocea (Rubiaceae, a common ornithophilous shrub found in the riparian forest understory in the Upper Paraná River floodplain, Brazil. Flowers are distylous and the style-stamen dimorphism is accompanied by other intermorph dimorphisms in corolla length, anther length, and stigma lobe length and form. We did not observe strict reciprocity in the positioning of stigma and anthers between floral morphs. Flowering occurred during the rainy season, October to December. Nectar standing crop per flowerwas relatively constant throughout the day, which apparently resulted in hummingbirds visiting the plant throughout the day. Energetic content of the nectar in each flower (66.5J and that required daily by hummingbird visitors (up to 30kJ would oblige visits to hundreds of flowers each day, and thus movements between plants that should result in pollen flow. Three hummingbird species visited the flowers: the Gilded Sapphire (Hylocharis chrysura, the Black-throated Mango (Anthracothorax nigricollis, and the Glittering-bellied Emerald (Chlorostilbon aureoventris. The frequency of hummingbird visitation, nectar features, and the scarcity of other hummingbird-visited flowers in the study area, indicate that P. crocea is an important nectar resource for short-billed hummingbirds in the study site.Investigamos a morfologia floral, as características do néctar e a visita de beija-flores a Palicourea crocea (Rubiaceae, uma espécie ornitófila arbustiva comumente encontrada no sub-bosque da vegetação ripária na planície de inundação do Alto Rio Paraná, Brasil. As flores são distílicas, sendo o dimorfismo estilete-estames acompanhado por outras variações morfológicas no comprimento da corola, altura das anteras, comprimento das anteras e comprimento e forma das papilas estigmáticas. Não foi observada reciprocidade estrita na posição dos estigmas e