bluuebunny/crossref_metadata_2025_split huggingface dataset:
Time-of-Detection Method for Estimating Abundance From Point-Count Surveys
Authors: Alldredge Mathew W. , Pollock Kenneth H. , Simons Theodore R. , Collazo Jaime A. , Shriner Susan A. 
Published: September 2019

Abstract
Point-count surveys are often used to collect data on the abundance and distribution of birds, generally as an index of relative abundance. Valid comparison of these indices assumes that the detection process is comparable over space and time. These restrictive assumptions can be eliminated by estimating detection probabilities directly. We generalize a recently proposed removal model for estimating detection probabilities using a time-of-detection approach, which can account for more sources of variation in point-count data. This method is specifically designed to account for variation in detection probabilities associated with singing rates of birds. Our model accounts for both availability bias and detection bias by modeling the combined probability that a bird sings during the count, and the probability that it is detected given that it sings. The model requires dividing the count into several intervals and recording detections of individual birds in each interval. We develop maximum-likelihood estimators for this approach and provide a full suite of models based on capture-recapture models, including covariate models. We present two examples of this method: one for four species of songbirds surveyed in Great Smoky Mountains National Park using three unequal intervals, and one for the Pearly-eyed Thrasher (Margarops fuscatus) surveyed in Puerto Rico using four equal intervals. Models incorporating individual heterogeneity were selected for all data sets using information-theoretic model-selection techniques. Detection probabilities varied among count-time intervals, which suggests that birds may be responding to observers. We recommend applying this method to surveys with four or more equal intervals to reduce assumptions and to take full advantage of standard capture-recapture software. The time-of-detection approach provides a better understanding of the detection process, especially when singing rates of individual birds affect detection probabilities.
Estimación de la Abundancia en Puntos de Conteo Mediante el Método del Tiempo de Detección
Diurnal and Nocturnal Roost Site Fidelity of Dunlin (Calidris Alpina Pacifica) at Humboldt Bay, California
Authors: Conklin Jesse R. , Colwell Mark A. 
Published: September 2019

AbstractShorebird roosts are often considered traditional, on the basis of predictable occupancy by large numbers of birds over long periods. However, fidelity of individuals to roosts at fine spatial and temporal scales, particularly at night, has rarely been described. We compared diurnal and nocturnal use of high-tide roosts by radiotagged Dunlin (Calidris alpina pacifica) wintering (November-March) at Humboldt Bay, California. Despite high fidelity to the study area, fidelity to particular roosts was relatively low and highly variable. At night, Dunlin used fewer roosts, were more faithful to primary roosts, and moved shorter distances between successive roosts than during the day. Day and night roosts differed in location, habitat, and distance from tidal flats. At night, Dunlin made greater use of pasture, and less use of islands and manmade structures. Day and night strategies of high-tide space use by Dunlin may be related to differences in food availability or predation danger. Our results illustrate that notions of tradition and site fidelity are scale-dependent and that knowledge of space use across the full range of environmental conditions is necessary for appropriate management of shorebird habitat.Fidelidad a los Sitios de Descanso Diurnos y Nocturnos en Calidris alpina pacifica en la Bahía de Humboldt, California
High Connectivity and Minimal Genetic Structure Among North American Boreal Owl (Aegolius Funereus) Populations, Regardless of Habitat Matrix
Authors: Koopman Marni E. , Hayward Gregory D. , McDonald David B. 
Published: September 2019

AbstractHabitat connectivity and corridors are often assumed to be critical for the persistence of patchily distributed populations, but empirical evidence for this assumption is scarce. We assessed the importance of connectivity among habitat patches for dispersal by a mature-forest obligate, the Boreal Owl (Aegolius funereus). Boreal Owls demonstrated a lack of genetic structure (θ = 0.004 ± 0.002 [SE]) among subpopulations, regardless of matrix type and extent, which indicates that unforested matrix does not act as a barrier to dispersal for this vagile species. We found only slightly higher genetic distances (Cavalli-Sforza chord distances ranged from 0.015 to 0.025) among patchily distributed Rocky Mountain subpopulations as compared with largely contiguous boreal-forest subpopulations (0.013 to 0.019) and no evidence of a genetic split across the expansive high plains of Wyoming. Even the most isolated subalpine patches are connected via gene flow. As northern boreal forests continue to experience intensive harvest of mature stands, geographic dispersion of Boreal Owl habitat may begin to more closely resemble that found in the Rocky Mountains. We suggest that decreased connectivity poses much less of a threat to continued abundance of this mature-forest obligate than overall loss of nesting and foraging habitat. Assessment of the importance of corridors and connectivity should be conducted on a species-by-species basis, given the variation in response of species to discontinuity of habitat, even among closely related taxa or guilds.Alta Conectividad y Estructura Genética Mínima entre Poblaciones Norteamericanas de Aegolius funereus, Independientemente de la Matriz del Hábitat
Algemene en Schaarse Vogels van Nederland [Common and Scarce Birds of The Netherlands]
Authors: van der Linde Kim 
Published: September 2019

Abstract
The following critiques express the opinions of the individual evaluators regarding the strengths, weaknesses, and value of the books they review. As such, the appraisals are subjective assessments and do not necessarily reflect the opinions of the editors or any official policy of the American Ornithologists' Union.
Goudplevieren en Wilsterflappers: Eeuwenoude Fascinatie voor Trekvogels [Golden Plovers and Wilsternetters: A Century-old Fascination for Migratory Birds]
Authors: van der Linde Kim 
Published: September 2019

Abstract
The following critiques express the opinions of the individual evaluators regarding the strengths, weaknesses, and value of the books they review. As such, the appraisals are subjective assessments and do not necessarily reflect the opinions of the editors or any official policy of the American Ornithologists' Union.
Variation in the Wing Morphology of Western Sandpipers (Calidris Mauri) in Relation to Sex, Age Class, and Annual Cycle
Authors: Fernández Guillermo , Lank David B. 
Published: September 2019

AbstractWe analyzed differences in wing morphology between sexes and among age classes of Western Sandpipers (Calidris mauri) to assess possible relationships with differential migration, acrobatic aerial displays, and potential vulnerability to predation, using size-constrained component analysis. Data on wing morphology of all four sex and age classes were available from birds spending the nonbreeding season in northwestern Mexico, and data on females were available from throughout the annual cycle. During the nonbreeding season, females had longer and more pointed wings than males. Within each sex, adults had longer and more pointed wings than immature birds. Throughout the annual cycle, adult females tended to have longer and more pointed wings than immature females. The longer and more pointed wings of females are consistent with selection on flight efficiency for longer migration distances. The shorter and rounder wings of males are consistent with stronger selection for agility in flight during acrobatic aerial displays, but also with weaker selection for flight efficiency because of shorter migration distances. The rounder wings of immature birds are most consistent with stronger selection for take-off performance as an antipredator adaptation, at a cost of lower flight efficiency during long-distance migratory flight. Considering intraspecific sex and age class differences in wing morphology of species with differential migration complements interspecific comparisons assessing the relative importance of selective agents acting on this character.Variación en la Morfología del ala de Calidris mauri con Relación al Sexo, la Edad y el Ciclo Anual
A Test of Cues Affecting Habitat Selection by Wading Birds
Authors: Gawlik Dale E. , Crozier Gaea E. 
Published: September 2019

Abstract
We examined foraging-habitat selection by free-ranging wading birds presented with different social and environmental cues by conducting two experiments in eight replicate ponds adjacent to the northern border of the Florida Everglades. The first experiment examined the relative influence of a social (presence of a flock of decoys) and environmental (water depth) cue on the selection of ponds. The second experiment examined the influence of two environmental cues (water depth and fluctuating water level) on the selection of ponds. In the first experiment, wading birds were most attracted to ponds with both the presence of a flock of decoys and shallow water. The social and environmental cues both had the same attractive potential to wading birds. In the second experiment, birds were again attracted to ponds with shallow water; however, fluctuating water level had no significant influence on foraging-habitat selection. If birds do not perceive fluctuating water levels as a cue to habitat quality, then the well-documented relationship between nesting success and fluctuating water levels likely stems from birds responding to factors that covary with water-level changes.
Una Prueba de las Señales que Afectan la Selección de Hábitat por Aves Vadeadoras
The Antitrochanter of Birds: Form and Function in Balance
Authors: Hertel Fritz , Campbell Kenneth E. 
Published: September 2019

AbstractThe antitrochanter is a uniquely avian osteological feature of the pelvis that is located lateral to the postero-dorsal rim of the acetabulum. This feature makes the avian hip joint unique among all vertebrates, living and fossil, in that a significant portion of the femoral-pelvic articulation is located outside of the acetabulum. This additional acetabular articulation occurs between the neck of the femur and the antitrochanter, and operates as a hinge joint or ginglymus. It is complementary to the articulation of the head of the femur with the acetabulum, which is a pivot joint or trochoides. The size, location, and spatial orientation of the antitrochanter were determined for 77 species of birds representing a variety of hindlimb functions (e.g., highly cursorial, vertical clinging, foot-propelled diving) and spanning a wide range of body sizes (swifts to rheas). The area of the antitrochanter is a good predictor of body mass in birds; its position and orientation are reasonably consistent within hindlimb morphofunctional groups, but not among all birds. The antitrochanter serves as a brace to prevent abduction of the hindlimb and to absorb stresses that would otherwise be placed on the head of the femur during bipedal locomotion. The drum-in-trough-like form of the antitrochanter-femur articulation tends to assist in the transfer of long-axis rotational movements of the femur to the pelvis. The avian antitrochanter is a derived feature of birds that evolved as an aid in maintaining balance during bipedal terrestrial locomotion.El Antitrocánter en las Aves: Forma y Función en el Equilibrio
Rates Versus Counts: Fall Molts of Lucy's Warblers (Vermivora Luciae)
Authors: Rohwer Sievert , Navarro Adolfo G. , Voelker Gary 
Published: September 2019

AbstractNew specimens from Sinaloa, Mexico, as well as two older specimens, show that both adult and recently fledged Lucy's Warblers (Vermivora luciae) often move far south of their breeding grounds to molt in the tropical deciduous forests of northwestern Mexico. Remarkably, the first preformative (= first prebasic) molt is complete in Lucy's Warblers, including the replacement of flight feathers, primary coverts, and rectrices; thus, previous aging criteria based on the wear and appearance of these feathers are invalid. We suggest that the recent conclusion that Lucy's Warblers molt on their breeding grounds (Voelker and McFarland 2002) is an artifact of more collecting in the southwestern United States than in western Mexico during late summer. An index of relative collecting in Mexico and the United States, as well as data from constant-effort mist netting, suggest that most Lucy's Warblers move south to molt.Tasas versus Conteos: Mudas de Otoño de Vermivora luciae
Mark-Recapture-Recovery Modeling and Age-Related Survival in Little Penguins (Eudyptula Minor)
Authors: Sidhu Leesa A. , Catchpole Edward A. , Dann Peter 
Published: September 2019

AbstractWe analyzed yearly mark-recapture-recovery information collected over a 36-year period for the Little Penguins (Eudyptula minor) of Phillip Island in southeastern Australia. We show that it is feasible to model age-dependence for the survival, recapture, and recovery probabilities simultaneously, and that such a modeling scheme yields biologically realistic age structures for the model parameters. We provide illustrations of potentially erroneous results that may arise when researchers fail (1) to consider simultaneous age-dependence or (2) to detect annual variations that may mask age-dependence. From 1968 to 2004, 23,686 chicks were flipper-banded; 2,979 birds were encountered after fledging, and 1,347 were ultimately recovered dead. We found low survival of 17% in the first year of life, increasing to 71% in the second year of life, 78% in the third year, and 83% thereafter, and declining gradually after nine years of age. A population model allowing for immigration of birds from areas surrounding the study sites fits the observed stable population in the study sites.Modelado de Marca-Recaptura-Recuperación y Supervivencia Relacionada con la Edad en Eudyptula minor
Effects of Size and Migratory Behavior on the Evolution of Wing Molt in Terns (Sternae): A Phylogenetic-Comparative Study
Authors: Bridge Eli S. , Voelker Gary , Thompson Christopher W. , Jones Andrew W. , Baker Allan J. 
Published: September 2019

AbstractApproximately 60% of the 45 species of terns (Sternae) have an unusual form of wing molt in which a variable number of inner primaries and outer secondaries are replaced two or three times in a single year—a process that has been called “repeated molt.” Although several hypotheses have been proposed for the maintenance of repeated molt, few data exist regarding potential selective forces that may have favored the evolution of this molt strategy, and there are no explanations for the high degree of interspecific variation in the extent of repeated molt. Preliminary investigations indicated that large terns tended to have less repeated molt than small terns and that the presence of repeated molt appeared to be associated with migratory behavior. We examined these initial findings by combining data from the literature, from examinations of museum specimens, and from a recent molecular phylogeny of the terns to perform phylogenetic-comparative tests. First, we used independent contrasts to verify that the association between large terns and less repeated molt was significant and not a result of shared ancestry. Second, we used tests for binary character association to evaluate the apparent link between repeated molt and migratory behavior. The results of these tests, along with reconstructions of ancestral states, led to a potential explanation for the origin of repeated molt, in which a tropical, sedentary ancestor gave rise to several lineages that spread to temperate areas and adopted a migratory life history. With this shift to a more seasonal regime came shortened breeding periods and perhaps more time for molt, which could have led to modifications of the ancestral molting strategy and the origin of repeated molt.Efectos del Tamaño y del Comportamiento Migratorio en la Evolución de la Muda del Ala en los Gaviotines (Sternae): Un Estudio Filogenético Comparativo
Historical Biogeography of the New World Solitaires (Myadestes SPP)
Authors: Miller Matthew J. , Bermingham Eldredge , Ricklefs Robert E. 
Published: September 2019

AbstractSolitaires (Myadestes spp.) are montane-forest birds that are widely distributed throughout the New World, ranging from Alaska to northern Bolivia and including both Hawaii and the West Indies. To understand the origins of this impressive distribution, we used five mitochondrial gene sequences to reconstruct the historical biogeography of the genus. The resulting phylogeny indicates a rapid initial spread of the genus to occupy most of its contemporary continental range at least as far south as lower Mesoamerica, plus Hawaii and the Greater Antilles. The North American M. townsendi appears to be the sister taxon of the rest of Myadestes. Myadestes obscurus of Hawaii is more closely allied to Mesoamerican lineages than to M. townsendi. The strongly supported sister relationship of the two West Indian taxa, M. elisabeth and M. genibarbis, indicates a single colonization of the West Indies. A more recent node links the Andean M. ralloides to the Mesoamerican M. melanops and M. coloratus. A standard molecular clock calibration of 2% sequence divergence per million years for avian mitochondrial DNA suggests that the initial diversification of Myadestes occurred near the end of the Miocene (between 5 and 7.5 mya). Cooler temperatures and lower sea levels at that time would have increased the extent of montane forests and reduced overwater dispersal distances, possibly favoring range expansion and colonization of the West Indies. The split between South American and southern Mesoamerican lineages dates to ∼3 mya, which suggests that Myadestes expanded its range to South America soon after the Pliocene rise of the Isthmus of Panama. Despite the demonstrated capacity of Myadestes for long-distance dispersal, several species of Myadestes are highly differentiated geographically. Phylogeographic structure was greatest in the West Indian M. genibarbis, which occurs on several islands in the Greater Antilles and Lesser Antilles, and in the Andean M. ralloides. The phylogeographic differentiation within M. ralloides was not anticipated by previous taxonomic treatments and provides a further example of the importance of the Andes in the diversification of Neotropical birds. Overall, the historical biogeography of Myadestes suggests that range expansion and long-distance dispersal are transient population phases followed by persistent phases of population differentiation and limited dispersal.Biogeografía Histórica de los Zorzales del Género Myadestes
Metabolic Routing of Dietary Nutrients in Birds: Effects of Dietary Lipid Concentration on δ13C of Depot Fat and Its Ecological Implications
Authors: Podlesak David W. , McWilliams Scott R. 
Published: September 2019

AbstractDuring migration, many songbirds eat primarily fruit while depositing fat. Given that some fruits contain mostly carbohydrate and others contain mostly lipid, the ability of birds to fatten may depend on the macronutrient composition of the fruit. Stable isotopes of carbon may be useful in determining the source of nutrients used for synthesizing fat, because the enzyme that regulates the transfer of carbon skeletons from carbohydrate into fat synthesis has a higher affinity for 12C than for 13C, whereas dietary lipids can be directly incorporated into animal fat. Thus, fat stores of animals that are synthesized directly from dietary lipid should have isotopic signatures similar to dietary lipid, whereas biosynthesis of fats from dietary carbohydrates should produce changes in isotopic signatures. We tested these predictions by manipulating the concentrations and isotopic signatures of macronutrients in diets fed to Yellow-rumped Warblers (Dendroica coronata). The δ13C of depot fat in birds fed high-lipid diets was similar to that of dietary lipid, whereas δ13C of depot fat in birds fed low-lipid diets indicated that a combination of dietary lipid and carbohydrate were used to synthesize depot fat. Models that incorporated 8% discrimination between dietary carbohydrate and depot fat consistently estimated the proportion of dietary lipid and carbohydrate routed into depot fat. Stable-isotope analysis of macronutrients in the diet of wild birds combined with estimates of the effects of diet composition on the isotopic signature of depot fat in birds offer a method to identify the relative importance of nutritional resources used by songbirds to deposit fat.Rutas Metabólicas de Nutrientes Dietarios en Aves: Efectos de la Concentración de Lípidos Dietarios sobre δ13C en los Depósitos de Grasa y sus Implicancias Ecológicas
Phenology of Tropical Birds in Peninsular Malaysia: Effects of Selective Logging and Food Resources
Authors: Yap Charlotte A-M. , Sodhi Navjot S. , Peh Kelvin S-H. 
Published: September 2019

AbstractThe increasing prevalence of selective logging in Southeast Asian tropical rainforests compels much-needed studies to examine its effects on the vital life-cycle events of their resident understory birds, which are particularly sensitive to such degradation. Food abundance, which can be an important factor in avian phenology, may be affected by selective logging. Therefore, studies that compare food abundance and breeding and molting occurrence simultaneously at the same sites are important for the ecological monitoring of such logging regimes. Using bimonthly mist netting in two rainforest areas in Peninsular Malaysia, we assessed the breeding and molting occurrence and diets of understory birds and compared the abundance of food resources in unlogged forests and forests that had been selectively logged 30 years before. Our study revealed no differences between forest types in overall understory-resident bird abundance; comparative species richness; feeding-guild composition; breeding and molting occurrence and temporal variation; or arthropod, fruit, and flower abundance. The similarity in food resources could account for the similarity in avian phenological characteristics between forest types. Increased breeding corresponded with increased food abundance at the feeding-guild level, and dietary data supported these findings. Breeding cycles of sensitive indicator groups such as understory resident birds are likely to depend on food abundance and forest structure and, thus, on selective logging. Our observation of undiminished avian breeding and molting occurrence in selectively logged forests is an encouraging indication of their conservation potential. However, we emphasize that differences in selective logging practices could affect the forest structure and avifauna differently. Setting thresholds for extraction and regeneration time and subscribing to minimum-impact methods that reduce collateral damage are essential if selectively logged areas are to maintain most of their initial biodiversity.Fenología de Aves Tropicales en Malasia Peninsular: Efectos de la Tala Selectiva y los Recursos Alimenticios