bluuebunny/crossref_metadata_2025_split huggingface dataset:
No Support for a Genetic Basis of Mandible Crossing Direction in Crossbills (Loxia SPP)
Authors: Edelaar Pim , Postma Erik , Knops Peter , Phillips Ron 
Published: September 2019

AbstractUnusual among birds, the bill tips in crossbills (Loxia spp.) overlap in the vertical plane, with the tip of the lower mandible to either the left or right of the tip of the upper mandible when viewed from above. Patterns observed in wild populations and experimental foraging data suggest that a 1:1 ratio of left- to right-crossing individuals is maintained by frequency-dependent natural selection in some populations, and that genetic drift causes deviation from a 1:1 ratio in other populations. Both processes require a genetic basis for this remarkable polymorphism, yet few data are available that address whether, and how, mandible crossing direction is heritable. To test for a genetic basis of this trait (single or quantitative, autosomal or sex-linked), we analyzed resemblance in mandible crossing direction between related captive-bred individuals of several crossbill taxa with standard statistical techniques as well as modern animal model methodology. Surprisingly, we did not find statistically significant support for a genetic basis of mandible crossing direction. Comparisons of the ratio of left- to right-crossing males and females in wild populations also did not support a sex-linked quantitative genetic basis. We conclude that mandible crossing direction may have uncharacteristically low heritability, but we cannot rule out that it is nongenetically determined.La Dirección de Cruzamiento de la Mandíbula en las Especies de Loxia no Presenta Base Genética
Phylogeography of the American Woodcock (Scolopax Minor): Are Management Units Based on Band Recovery Data Reflected in Genetically Based Management Units?
Authors: Rhymer Judith M. , McAuley Daniel G. , Ziel Heather L. 
Published: September 2019

AbstractInformation on population connectivity throughout the annual cycle has become more crucial, because populations of many migratory birds are in decline. One such species is the American Woodcock (Scolopax minor), which inhabits early-successional forests in eastern North America. Although band recoveries have proved useful for dividing populations of this game bird species into an Eastern Region and Central Region for management purposes, these data do not provide enough detail to determine the breeding population of origin of birds recovered on stopover and wintering areas. To obtain more fine-scale data, we undertook a phylogeographic study of American Woodcock populations throughout their primary breeding range in the eastern United States and Canada using mitochondrial DNA (mtDNA) sequences from the hypervariable control region I (CRI) and ND6 gene. Despite high haplotype diversity, nucleotide diversity was low and there was no phylogeographic structure among American Woodcock populations across the species range, with birds from many states and provinces in both management regions sharing identical haplotypes. Results suggest recent or ongoing gene flow among populations, with asymmetric movement of birds between migration flyways. As has been demonstrated for several other avian species in North America, American Woodcock appear to have undergone a rapid population expansion following the late Pleistocene glacial retreat. Thus, a combination of historical demographic factors and recent or ongoing gene flow mask any population structure based on mtDNA that might accrue from philopatry to breeding areas observed in studies of marked birds.Phylogéographie de Scolopax minor: Est-ce que les Unités de Gestion Basées sur les Données de Retour de Bagues Reflètent les Unités de Gestion Basées sur la Génétique?
No Evidence for Adaptive Differential Sex Allocation in Red Junglefowl (Gallus Gallus)
Authors: Parker Timothy H. 
Published: September 2019

AbstractIn many situations, selection should favor females that bias the sex ratio of their offspring. Two commonly examined factors potentially influencing off- spring sex ratio are paternal ornamentation and maternal condition. Male junglefowl with larger combs are attractive to females. I housed female Red Junglefowl (Gallus gallus) with sterile male consorts and artificially inseminated them with sperm from other males that the females never saw. I found no relationship between either the comb size of the consort or the comb size of the sperm donor and the sex ratio of the offspring. I previously reported a significant sex ratio bias related to maternal mass in Red Junglefowl. However, that analysis was based on sex ratio data not weighted for brood size and assuming a normal distribution. Here, I show that this effect disappears when I conduct a more appropriate analysis weighting sex ratio according to brood size and accounting for the binomial error distribution. I also failed to find evidence that male chicks hatch from larger eggs than female chicks. These results suggest that Red Junglefowl females may not bias the sex ratio of their brood in response to either their own condition or the attractiveness of the males with whom they copulate. Furthermore, these results demonstrate the importance of choosing the correct methods of sex ratio analysis.Falta de Evidencia de Asignación Adaptativa Diferencial entre Sexos en Gallus gallus
Boluses: An Effective Method for Assessing the Proportions of Cephalopods in the Diet of Albatrosses
Authors: Xavier José C. , Croxall John P. , Cresswell Kate A. 
Published: September 2019

AbstractThe method of collecting and analyzing boluses to characterize the cephalopod diet of albatrosses has been used in many diet studies. However, no study has validated this method. We compared boluses and stomach samples from Gray-headed Albatrosses (Thalassarche chrysostoma) and Black-browed Albatrosses (T. melanophris) to (1) study the consumption and diversity of cephalopods in these species, (2) investigate biases associated with each sampling method, and (3) estimate the number of samples needed to characterize these albatross’s cephalopod diet. We found that collection and analysis of boluses is a simple, efficient, and noninvasive method for assessing the cephalopod diet of these albatross species, but it is inadequate for characterizing the more easily digestible dietary components, such as fish and crustaceans. Both boluses and stomach samples showed that the two albatross species fed on cephalopods of similar sizes and from the same families (Ommastrephidae, Onychoteuthidae, and Cranchiidae). Furthermore, the main prey species (Martialia hyadesi, Kondakovia longimana, and Galiteuthis glacialis) and the total number of cephalopod species consumed (18–24 species) were the same for both albatrosses. To include all cephalopod species, using a sample-randomization technique, a minimum of 61 and 43 boluses were needed for Gray-headed and Black- browed albatrosses, respectively; but to adequately describe the diversity and size frequency of the main prey species, 82 and 371 boluses would be needed.Les Pelotes de Réjection: Une Méthode Efficace pour Évaluer la Proportion de Céphalopodes dans le Régime Alimentaire chez les Albatros
Population Genetics of the Galápagos Hawk (Buteo Galapagoensis): Genetic Monomorphism Within Isolated Populations
Authors: Bollmer Jennifer L. , Whiteman Noah K. , Cannon Michelle D. , Bednarz James C. , Vries Tjitte de , Parker Patricia G. 
Published: September 2019

Abstract
Because of their smaller size and isolation, island populations tend to be more divergent and less genetically variable than mainland populations. We collected DNA samples from nine Galápagos Hawk (Buteo galapagoensis) island populations, covering the species’ entire range. Neutral minisatellite DNA markers were used to calculate within-island genetic diversity and between-island genetic differentiation (FST). Typically, these markers mutate too quickly to be informative in such studies. However, in very small, isolated populations, concerns about high mutational rate are obviated by the relative force of genetic drift. Individuals within islands had the highest levels of reported genetic uniformity of any natural bird population, with mean within-population band-sharing similarity values ranging from 0.693 to 0.956, increasing with decreasing island size. Galápagos Hawks exhibit cooperative polyandry to varying degrees across islands; however, we did not find an association between degree of polyandry and genetic variability. Between-island FST values ranged from 0.017 to 0.896, with an overall archipelago value of 0.538; thus, most populations were genetically distinct. Also, we documented higher levels of genetic similarity between nearby populations. Our results indicated negligible gene flow among most Galápagos Hawk populations, and genetic drift has played a strong role in determining structure at these minisatellite loci.
Genética de Poblaciones de Buteo galapagoensis: Monomorfismo Genético dentro de Poblaciones Aisladas
Phylogenetic Relationships of the Madagascar Pygmy Kingfisher (Ispidina Madagascariensis)
Authors: Marks Ben D. , Willard David E. 
Published: September 2019

Abstract
The avifauna of Madagascar presents a complicated taxonomic and biogeographic problem. Although Madagascar was once connected to Africa, the birds of the island are not all of African origin. The Madagascar Pygmy Kingfisher (Ispidina madagascariensis) is sometimes placed in the African genus Ispidina and sometimes in the Southeast Asian genus Ceyx. We sequenced 755 base pairs of mitochondrial DNA from a fragment of the NADH dehydrogenase subunit II (ND2) and from the complete NADH dehydrogenase subunit III (ND3). We used these data to construct phylogenetic hypotheses for the Alcedinidae. Using these phylogenies, we evaluate previous hypotheses of relationships of I. madagascariensis. Although we cannot reject the hypothesis that I. madagascariensis is indeed a member of Ispidina, tree-building analyses support a relationship not with Ispidina or Ceyx, but instead with members of the African genus Corythornis. These data suggest that certain behaviors and plumage types have evolved several times in the Alcedinidae.
Relations Phylogénétiques de Ispidina madagascariensis
Tracking Ocean Wanderers: The Global Distribution of Albatrosses and Petrels
Authors: Veit Richard R. 
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.
Diet Influences Life Span in Parrots (Psittaciformes)
Authors: Munshi-South Jason , Wilkinson Gerald S. 
Published: September 2019

AbstractEvolutionary hypotheses regarding longevity predict that life span should increase as extrinsic mortality rates decrease. Specifically, a decline in age-specific survival and fertility should evolve and decrease life span in proportion to the magnitude of the mortality risk. We examined these ideas using a new data set on maximum longevity, ecology, and life history of 162 parrot species (Psittaciformes). Parrots are generally long-lived but exhibit remarkable variation in life span between similar-sized genera, with particularly long-lived species occurring in the Cacatua, Calyptorhynchus, and Amazona. After controlling for both body size and phylogenetic ancestry using a phylogenetic supertree of all 352 parrot species, type of diet and communal roosting explain significant variation in parrot life span, but the influence of communal roosting is statistically dependent on an association with diet type. We suggest that extreme longevity in parrots has evolved in response to species-specific characteristics of diet, habitat, and behavior that influence extrinsic mortality rates.La Dieta Influencia la Longevidad en los Psittaciformes
Nests Without Eggs: Abandonment or Cryptic Predation?
Authors: Maddox J. Dylan , Weatherhead Patrick J. 
Published: September 2019

AbstractWe determined whether nests that did not receive eggs was attributable to cryptic nest predation (i.e. predation of eggs laid between nest checks) or nest abandonment in Common Grackles (Quiscalus quiscula). Nest predation was extremely low (∼2%), whereas more than 44% of 427 nests found during nest building never received an egg; this indicates that nest abandonment accounted for most nests without eggs. Nest construction was completed for 32% of nests that were abandoned. Few nests known to have received eggs were abandoned. As the breeding season progressed, both nest abandonment and time from nest completion to first egg decreased. It has been proposed that the delay in egg laying early in the season allows females to optimize timing of egg laying. Nest abandonment may also serve this purpose, but seems an unnecessarily expensive mechanism. Alternatively, nest abandonment could be involved with mate switching. Understanding why nests are abandoned requires data on the associated ecological circumstances, in addition to accurate identification of instances of abandonment. The latter requires distinguishing abandonment from cryptic predation. Rates of nest abandonment can be estimated for populations by using rates of known nest predation during egg laying. For individual nests, however, distinguishing abandonment from cryptic predation requires detailed observation (e.g. video cameras), except in circumstances such as ours, where predation is extremely low.Nidos sin Huevos:?Abandono o Depredación Críptica?
Are Multiple Infections More Severe for Purple Martins (Progne Subis) Than Single Infections?
Authors: Davidar Priya , Morton Eugene S. 
Published: September 2019

AbstractBetween 1986 and 1993, we studied a breeding colony of Purple Martins (Progne subis) in Maryland that were chronically infected with two blood parasites: Haemoproteus prognei, a haematozoan, and an unidentified filarial nematode. We assessed whether cross-infections are more severe than single infections by comparing the return rates of birds infected with either or both parasites and the return rates of uninfected controls. Birds were captured every year and banded, and blood smears were taken for parasite screening. Average prevalence of filaria among the 400 birds screened during this period was 22%. Birds usually became infected by their second year (SY), and infected SY birds had significantly lower return rates than older birds. Cross-infections were rare (8%) and were fatal in 90% of cases. With one exception, birds infected with H. prognei acquired filaria as a second infection, which suggests that although both blood parasites are relatively benign for older Purple Martins, co-infection with a second parasite (in this case, H. prognei) almost always results in death.Est-ce que les Infections Multiples Sont Plus Sévères que les Infections Simples chez Progne subis?
Stability of Pentosidine Concentrations in Museum Study Skins
Authors: Fallon Jesse A. , Radke William J. , Klandorf Hillar 
Published: September 2019

AbstractAccumulation of the advanced glycation endproduct pentosidine (Ps) in skin collagen is strongly correlated with age of adult birds. This allows age estimates to be made without use of banding data. We examined the stability of Ps in museum study skins. We took skin samples from six Ruffed Grouse (Bonasa umbellus) study skins at three-month intervals over the course of one year. The data revealed no significant variation in Ps concentrations within individual birds, which indicates that Ps is stable in study skins for at least 12 months. These data suggest that inferences concerning age might be made from similarly prepared specimens from collections around the world. Additionally, we found significant variations in Ps concentrations in skin collagen among six different locations on the study skins. This suggests that care and consistency are important when excising skin for Ps measurement and age estimation in birds.Estabilidad de las Concentraciones de Pentosidina en Pieles de Estudio de Museo
Is Melanin a Defense Against Feather-Feeding Lice?
Authors: Bush Sarah E. , Kim Dukgun , Moyer Brett R. , Lever Jackson , Clayton Dale H. 
Published: September 2019

AbstractThe adaptive basis of plumage color has received much attention, including the finding that color can reveal information about parasite loads to potential mates. A related possibility, that color may be a direct defense against parasites, has received less attention. Melanin makes feathers tough and more resistant to wear and tear. Melanin may also make feathers more difficult for feather-feeding parasites to eat. We explored the role of melanin as a possible ectoparasite defense using Rock Pigeons (Columba livia) and their feather-feeding lice (Insecta: Phthiraptera). Rock Pigeons are an ideal species for such work because of the extreme variation in the feathers of different color morphs, ranging from melanin-rich black to melanin-free white individuals. We tested the effect of melanin on lice in several ways. First, we compared the natural louse loads of free-ranging pigeons to see whether the more melanistic color morphs had fewer lice. We also did laboratory assays in which we measured the survival and reproductive success of pigeon lice forced to feed on feathers with different amounts of melanin, and we compared the quantities of feather material consumed by these lice. Finally, we tested the habitat and feeding preferences of lice exposed to feathers with different amounts of melanin. None of our tests revealed any effect of melanin on lice. We conclude that melanin is not, at least in Rock Pigeons, a defense against feather lice.¿Es la Melanina una Defensa Contra los Piojos que se Alimentan de Plumas?
Effects of Prescribed Burns and Bison (Bos Bison) Grazing on Breeding Bird Abundances in Tallgrass Prairie
Authors: Powell Alexis F. L A. 
Published: September 2019

AbstractGrassland birds have declined more than any other avian assemblage in North America, with nearly every species showing negative population trends. In the Flint Hills of Kansas, the largest remnant of the tallgrass prairie biome, annual spring burning of rangeland has recently replaced burning every 2–3 years. I examined effects of different burning and bison (Bos bison) grazing regimes on June abundances of seven bird species using a 23-year data set from the Konza Prairie Biological Station. Fire significantly affected the abundances of six of the seven species. Effects varied among species but, notably, four grass-dependent species—Grasshopper Sparrow (Ammodramus savannarum), Henslow’s Sparrow (A. henslowii), Dickcissel (Spiza americana), and Eastern Meadowlark (Sturnella magna)— and the shrub-dependent Bell’s Vireo (Vireo bellii)—were least abundant or absent at sites in the breeding season immediately following burning. Upland Sandpipers (Bartramia longicauda) were most abundant at sites in the season following burning, whereas Brown-headed Cowbirds (Molothrus ater) exhibited no significant response. Bison grazing increased abundance of Upland Sandpiper and Grasshopper Sparrow, nearly eliminated Henslow’s Sparrow, and (in combination with recent fire) lowered the abundance of Dickcissel. Although fire and grazing are natural forces that maintain tallgrass prairie, their action was, until recently, intermittent and patchy, providing grassland birds with a variety of levels of disturbance. If the vast Flint Hills prairie is to serve as a grassland bird stronghold, the region-wide practice of annual burning with intensive grazing must be replaced with alternatives that restore heterogeneity to the landscape.Efectos de las Quemas Programadas y del Pastoreo de los Bisontes sobre la Abundancia de Aves Reproductivas en Praderas de Pasto Alto
A Phylogenetic Perspective on the Evolution of Chromatic Ultraviolet Plumage Coloration in Grackles and Allies (Icteridae)
Authors: Eaton Muir D. 
Published: September 2019

AbstractPlumage traits have been studied intensely for more than a century, especially bright and exaggerated plumage. A large body of evidence across a range of avian taxa supports sexual selection as a major evolutionary force acting on plumage colors. The discovery of ultraviolet (UV) coloration in avian plumage resulted in the extension of sexual selection hypotheses to explain the evolution of potential UV plumage traits. However, there have been no comparative evolutionary studies elucidating the origin of UV signals in birds. Here, I used a comparative phylogenetic approach to investigate the evolution of chromatic UV plumage colors in the grackles-and-allies clade of the New World blackbirds (Icteridae). On the basis of reflectance data collected from museum study skins, I have determined that UV plumage signals have evolved multiple times from an ancestral condition that lacked UV plumage signals, with very few unambiguous reversals. Although UV plumage has evolved in both males and females, there have been significantly more evolutionary changes in male UV plumage characters. Concentrated changes tests and correlations of independent contrasts reveal evidence for sexual selection of some male UV plumage characters, as well as an increase in UV plumage coloration for species found in open habitats. These results support the use of objective assessments of avian colors (i.e. spectrophotometry) to properly interpret patterns of plumage evolution generally, and they suggest the need for behavioral studies on the function of chromatic UV signals in several blackbird species.Una Perspectiva Filogenética sobre la Evolución de la Coloración Ultravioleta en los Changos y Chamones (Icteridae)
Costs of Egg Punctures and Parasitism by Shiny Cowbirds (Molothrus Bonariensis) at Creamy-Bellied Thrush (Turdus Amaurochalinus) Nests
Authors: Astié Andrea A. , Reboreda Juan C. 
Published: September 2019

AbstractMost studies on cowbird parasitism have focused on its effects on parasitized nests, whereas few have considered the costs at nests that cowbirds visit but at which they do not lay eggs. Shiny Cowbirds (Molothrus bonariensis) peck and puncture host eggs both in nests where they lay eggs and in unparasitized nests. We analyzed the effect of egg punctures in unparasitized and parasitized nests of a large host, the Creamy-bellied Thrush (Turdus amaurochalinus; hereafter “thrush”), as well as the costs of Shiny Cowbird eggs and chicks in this host’s nests. We determined thrush egg survival, hatching success, and chick survival in successful nests, and nest survival during the egg and nestling stages. Frequency of parasitism was 60%, and its intensity 1.6 ± 0.1 eggs nest−1. Number of host eggs punctured was positively associated with intensity of parasitism. The host’s eggs were frequently punctured in parasitized nests (71%) and in unparasitized nests (42%). Egg punctures reduced the number of eggs at hatching in 23% and 49% of unparasitized and parasitized nests, respectively. Nests with egg punctures had a lower survival rate than nests without them, but nest survival was not associated with parasitism. Presence of a Shiny Cowbird egg was associated with a decrease in the hatching success of host eggs, but presence of a Shiny Cowbird chick did not have any detrimental effect on either the survival and growth rate of host chicks in successful nests or the survival of the whole nest. Our results show that egg punctures were the primary determinant of thrush reproductive success. Consequently, comparison of unparasitized and parasitized nests gives an incomplete estimation of the effects of Shiny Cowbirds on host reproductive success, because the cost of egg punctures is also important in nests where there is no Shiny Cowbird egg laying.Costos de la Perforación de Huevos y el Parasitismo por Molothrus bonariensis en Nidos de Turdus amaurochalinus