bluuebunny/crossref_metadata_2025_split huggingface dataset:
Growth and Energy Requirements of Captive-Reared Common Loon (Gavia Immer) Chicks
Authors: Fournier François , Karasov William H. , Kenow Kevin P. , Meyer Michael W. 
Published: September 2019

AbstractWe measured the energy requirements during postnatal development of six hand-reared Common Loon (Gavia immer) chicks using continuous feeding trials and doubly labeled water. At fledging, the mean (± SE) body mass of chicks was 3,246 ± 51 g. They reached asymptotic body mass in ≈66 days and had a mean growth rate constant of 0.089 ± 0.002 day−1, which was greater than growth rate constants of other, similar-sized precocial birds. Between hatch and day 66, chicks allocated 16.5% of their metabolizable energy to new tissue, lower than the average for other bird species (20%), which might be expected considering their precocial mode of development. There was a developmental change in the assimilation efficiency of food (metabolizable energy coefficient), with a mean of 0.64 ± 0.03 in chicks aged 21 days, rising to 0.83 ± 0.07 in chicks aged 35 days.Les besoins en énergie durant la croissance chez des jeunes Gavia immer élevés en captivité
Cooperative Display and Lekking Behavior of the Lance-Tailed Manakin (Chiroxiphia Lanceolata)
Authors: DuVal Emily H. 
Published: September 2019

Abstract
Male Lance-tailed Manakins (Chiroxiphia lanceolata) perform multi-male courtship displays for females. To characterize the behavioral repertoire and the lek spatial organization of this species, I observed lekking males on Isla Boca Brava, Chiriquí Province, Panamá. Breeding began in March and continued through June, though courtship displays were recorded as late as November. Males were active throughout the day at display areas on the dispersed lek. Display areas were spaced 102 ± 30 m apart and averaged 2,480 ± 1,060 m2 in area (range: 525–4,500 m2; n = 24 display areas). The behavioral repertoire of Lance-tailed Manakins included 11 dance display elements, 7 common vocalizations, and 2 types of male-male duet songs. Duet songs and multimale dances for females were cooperative efforts by male pairs and included display elements that were never performed during courtship displays by solitary males. However, males performed both cooperative and entirely solo displays for females that ended in successful copulation, which suggests that cooperation is not obligate in this species, at least on the level of individual displays. Two sonations, or nonvocal communicative sounds, were noted during courtship displays: low-amplitude pulses of noise produced in rapid sets of 7–30 clicks during slow flight displays, and a low-frequency woosh produced at the nadir of swoop displays. The Lance-tailed Manakin display repertoire provides information useful in comparative analyses of the origin and evolution of display behavior within the manakin clade and in studies of the adaptive consequences of individual behavior within this species.
Exhibición Cooperativa y Comportamiento de Asambleas de Cortejo en Chiroxiphia lanceolata
Which Life-History Components Determine Breeding Productivity for Individual Songbirds? A Case Study of the Louisiana Waterthrush (Seiurus Motacilla)
Authors: Mattsson Brady J. , Cooper Robert J. 
Published: September 2019

Abstract
Population dynamics of small songbirds are driven in part by fecundity and productivity (i.e., the number of young that fledge and survive the dependent stage, respectively, per adult female per year). Because of the challenges of obtaining empirical estimates for productivity or fecundity, some researchers predict fecundity using a three-factor model or more complex models such as those developed by Pease and Grzybowski (1995) or Farnsworth and Simons (2001, 2005). All these models generate a single prediction with no estimate of variability around the prediction. We developed an individual-based model that provides predictions of productivity and measurements of variability surrounding the predictions for simulated populations of Louisiana Waterthrushes (Seiurus motacilla) based on various aspects of their breeding cycle. Our empirical estimate of productivity in Louisiana Waterthrush (x̄ ± SD = 1.50 ± 1.45) was similar to that provided by our individual-based model (1.07 ± 1.24). On the basis of our model, productivity was most sensitive to and increased dramatically with increasing fledgling survival, daily nest survival, followed by nestling survival. The remaining four factors had weak, if any, effects on productivity. When compared with our individual-based model, the three-factor and Pease and Grzybowski (1995) models often produced higher predictions of fecundity, ≤2.1 additional young fledged per female. This is likely attributable to the addition of a renesting rate in our individual-based model. The Farnsworth and Simons model often produced predictions that were similar to those from our individual-based model. We believe that our individual-based model is an improvement over most existing songbird-fecundity models and can be generalized to accommodate other breeding factors, including brood parasitism and temporal variability.
¿Cuáles Componentes de la Historia de Vida Determinan la Productividad Reproductiva Individual en las Aves Canoras? Un Estudio de Caso con Seiurus motacilla
Southwestern Willow Flycatchers (Empidonax Traillii Extimus) in a Grazed Landscape: Factors Influencing Brood Parasitism
Authors: Brodhead Katherine M. , Stoleson Scott H. , Finch Deborah M. 
Published: September 2019

AbstractBrood parasitism by Brown-headed Cowbirds (Molothrus ater; hereafter “cowbirds”) is an important factor contributing to the endangered status of the Southwestern Willow Flycatcher (Empidonax traillii extimus, hereafter “flycatcher”). We report on factors that influence brood parasitism on the flycatcher using seven seasons of nest data (n = 491 nests) collected in riparian patches comprising cottonwood (Populus fremontii), willow (Salix spp.), and boxelder (Acer negundo) along the Gila River in southwest New Mexico. We quantified habitat and landscape characteristics that might be associated with higher levels of parasitism and assessed the correlation between those and the observed incidence of nest parasitism. Given that cowbirds associate with cattle, we were particularly interested to determine whether the distance to active summer grazing would influence the frequency of brood parasitism. We found an apparent negative trend between the distance to grazing and brood parasitism, but this trend was not statistically significant. Rather, brood parasitism was more strongly correlated with characteristics of the habitat. Specifically, nests in larger patches, and nests built near the patch edge adjacent to the river, were more susceptible to parasitism, which suggests that these areas are preferred nesting habitat for cowbirds because of a potentially greater abundance of hosts. Parasitism was significantly lower within the core of large patches, but the insulating effect was not evident in small and medium-sized patches. Higher nest height was strongly correlated with lower probability of parasitism, most notably for nests in boxelders. Nests in boxelders were less susceptible to parasitism, whereas nests in willows were more susceptible to parasitism. We discuss the results in the context of other studies. We recommend that management efforts to recover the flycatcher should focus on increasing quality habitat, and we suggest that cattle management should focus on eliminating the adverse effects of grazing on riparian health as a more feasible option than removing cattle far enough from riparian corridors so as to preclude parasitism.Empidonax traillii extimus en un Paisaje con Pastoreo: Factores que Influyen sobre el Parasitismo de la Nidada
Improving Estimates of Bird Density Using Multiple- Covariate Distance Sampling
Authors: Marques Tiago A. , Thomas Len , Fancy Steven G. , Buckland Stephen T. 
Published: September 2019

AbstractInferences based on counts adjusted for detectability represent a marked improvement over unadjusted counts, which provide no information about true population density and rely on untestable and unrealistic assumptions about constant detectability for inferring differences in density over time or space. Distance sampling is a widely used method to estimate detectability and therefore density. In the standard method, we model the probability of detecting a bird as a function of distance alone. Here, we describe methods that allow us to model probability of detection as a function of additional covariates—an approach available in DISTANCE, version 5.0 (Thomas et al. 2005) but still not widely applied. The main use of these methods is to increase the reliability of density estimates made on subsets of the whole data (e.g., estimates for different habitats, treatments, periods, or species), to increase precision of density estimates or to allow inferences about the covariates themselves. We present a case study of the use of multiple covariates in an analysis of a point-transect survey of Hawaii Amakihi (Hemignathus virens).Amélioration des estimations de densité d’oiseaux par l’utilisation de l’échantillonnage par la distance avec covariables multiples
A Tody (Alcediniformes: Todidae) From The Early Oligocene of Germany
Authors: Mayr Gerald , Knopf Charles W. 
Published: September 2019

AbstractWe describe a postcranial skeleton of a stem-group tody (Aves: Alcediniformes: Todidae) from the early Oligocene of Germany. The fossil is tentatively assigned to Palaeotodus itardiensisMourer-Chauviré, 1985, which previously was known only from a few incomplete bones from the early Oligocene of France. It is the most substantial fossil record of a Paleogene stem-group tody described so far and shows many previously unknown skeletal details. The specimen confirms the occurrence of Todidae, which are today restricted to the Caribbean Greater Antilles, in the Paleogene of Europe. The biogeographical significance of these finds depends on the phylogenetic relationships between Todidae and other alcediniform birds. If Todidae are not the sister taxon of Momotidae (motmots) as suggested by a recent phylogenetic analysis of molecular data, occurrence of stem-group Todidae in the Old World fossil record actually follows from the currently assumed Old World origin of alcediniform birds.Ein Todi (Alcediniformes: Todidae) aus dem unteren Oligozän Deutschlands
Survival and Habitat use of Mallard (Anas Platyrhynchos) Broods in the San Joaquin Valley, California
Authors: Chouinard Michael P. , Arnold Todd W. 
Published: September 2019

AbstractThe Central Valley of California is an important breeding area for Mallards (Anas platyrhynchos), but estimating recruitment rates for this population has been hampered by lack of data on duckling survival. To gain a better understanding of factors affecting brood and duckling survival, we radiomarked 56 brood hens and 112 ducklings (two per brood) on two actively managed wetland complexes in the San Joaquin Valley during 1996-1997. Total brood mortality was extensive, affecting 27 of 53 broods (51%). Survival of individual ducklings from hatching until 30 days of age was 24.8% (95% confidence interval: 0.178–0.335), with most mortality resulting from predation during the first 12 days of life. Survival differed between years and study areas but was unaffected by hatching date. Broods preferred reverse-cycle seasonal wetlands to more permanent wetlands throughout their first 30 days of life, and ducklings also had higher 2- to 30-day survival probabilities in reverse-cycle wetlands (x̄ ± SE = 0.755 ± 0.095) than in semipermanent-permanent wetlands (0.189 ± 0.056) or moist-soil units (0.173 ± 0.067). We recommend that waterfowl managers in the Central Valley provide reverse-cycle seasonal wetlands during the broodrearing period to enhance survival of locally breeding Mallards.Supervivencia y Uso de Hábitat por Nidadas de Anas platyrhynchos en el Valle de San Joaquín, California
Systematics and Evolution in the Tityrinae (Passeriformes: Tyrannoidea)
Authors: Barber Brian R. , Rice Nathan H. 
Published: September 2019

AbstractWe tested the monophyly and determined the phylogenetic relationships of the seven genera (Laniisoma, Laniocera, Iodopleura, Pachyramphus, Schiffornis, Tityra, and Xenopsaris) and 27 of the 31 recognized species of the subfamily Tityrinae using complete gene sequence data from the mitochondrial gene NADH dehydrogenase subunit 2. Monophyly of all seven genera was recovered using both weighted parsimony and Bayesian methods. Intergeneric relationships were nearly identical between the two methods and are largely in concordance with previous studies. Both analyses recovered two basal clades within the Tityrinae: one clade contained Schiffornis, Laniocera, and Laniisoma; the other clade consisted of Iodopleura, Tityra, Xenopsaris, and Pachyramphus. All genera in the Tityrinae that contained multiple species were monophyletic and are concordant with current taxonomy. We present the first phylogeny for Pachyramphus and suggest that Platypsaris is not valid. Character mapping of morphological, nest-construction, and breeding-system data on our phylogeny suggest conservative evolution of most characters. We recommend elevating the Tityrinae to family level.Sistemática y Evolución de los Tityrinae (Passeriformes: Tyrannoidea)
A Genotyping Assay to Determine Plumage Morph in The White-Throated Sparrow (Zonotrichia Albicollis)
Authors: Michopoulos Vasiliki , Maney Donna L. , Morehouse Caroline B. , Thomas James W. 
Published: September 2019

Abstract
In alternate plumage, the White-throated Sparrow (Zonotrichia albicollis) is polymorphic, such that individuals exhibit a median crown stripe that is either white or tan in color. This plumage polymorphism is believed to be caused by a chromosomal inversion and predicts many aspects of an individual’s aggressive and parental behavior, which makes this species an interesting and valuable subject for the study of the genetic basis of social behavior. Although the plumage polymorphism is well described, in practice the determination of morph for individual birds is not perfectly straightforward. Whereas morph can be assessed relatively easily in alternate plumage, birds in basic plumage tend to show coloration characteristic of both morphs. During the winter and fall, therefore, plumage morph cannot be determined with 100% accuracy by visual inspection alone. Here, we describe a genotyping assay that reliably predicts morph in alternate plumage. DNA from one drop of blood is amplified by PCR, digested and run on an agarose gel. The resulting banding patterns are used to distinguish white-striped from tan-striped birds with 100% accuracy. This method is fast and economical compared with karyotyping, is far less subjective than assessment of morph by plumage characteristics, and can be performed using any kind of sample from which DNA can be extracted.
Un test génotypique pour déterminer la forme du plumage chez Zonotrichia albicollis
Female-Biased Sex Ratio Arises After Parental Care in The Sexually Dimorphic Waved Albatross (Phoebastria Irrorata)
Authors: Awkerman Jill A. , Westbrock Mark A. , Huyvaert Kathryn P. , Anderson David J. 
Published: September 2019

Abstract
In response to evidence of sexual segregation at foraging grounds as well as male-biased band recoveries, we investigated the ontogeny of the female- biased adult sex ratio in the Waved Albatross (Phoebastria irrorata), an IUCN “critically endangered species” essentially endemic to Isla Española, Galapagos, Ecuador. Using a molecular technique to determine the sex of chicks and adults and known fate analysis of chicks during rearing, we found no evidence of a sex-ratio bias at hatching or fledging in three consecutive years with variable reproductive success. Although male chicks were significantly larger than females at fledging, survival to fledging of a large sample of male and female chicks did not differ. The sex ratio among a cohort of young adults at approximately the age of first breeding (eight years) also did not differ significantly from parity. Differential adult mortality, including male-biased mortality in fisheries, is the most probable cause of a female- biased population sex ratio, and is at least partially responsible for an apparent reduction in the number of breeding pairs of this species.
El Albatros Phoebastria irrorata, una Especie con Dimorfismo Sexual, Presenta una Mayor Proporción de Hembras Luego del Cuidado Parental
Time Since Contact and Gene Flow May Explain Variation in Hybrid Frequencies Among Three Dendroica Townsendi × D. Occidentalis (Parulidae) Hybrid Zones
Authors: Rohwer Sievert , Martin Paul R. 
Published: September 2019

AbstractHermit Warblers (Dendroica occidentalis) and Townsend’s Warblers (D. townsendi) meet and hybridize in three replicate zones in Washington and Oregon. Using male specimens, we show that the ratio of hybrid to parental phenotypes varies systematically across these three zones: there were 60.4% hybrids among 96 males from the Olympic zone, 43.3% hybrids among 411 males from the Washington Cascade zone, and 27.8% hybrids among 209 males from the Oregon Cascade zone. We found no evidence of habitat or climatic factors driving these systematic differences in hybrid frequencies, and we argue that they are related to differences among these zones in the immigration of pure parentals and time since contact. Building on earlier hypotheses about massive movement of the coastal zones (Rohwer and Wood 1998), we can infer that the Olympic and Washington Cascade zones are old and of similar age. The Washington Cascade zone, but not the Olympic zone, receives Townsend’s immigrants from the Rocky Mountains through the Okanogan high- lands, as shown by the linkage analyses in Rohwer et al. (2001). This immigration apparently accounts for the lower frequency of hybrids in the Washington Cascades. The Washington Cascade and Oregon Cascade zones are both situated adjacent to forest corridors that connect them to the Rocky Mountains to the east, so both of these zones should receive Townsend’s immigrants from the east (linkage analyses have yet to be done for the Oregon Cascades because the mitochondrial DNA haplo- types for these specimens have not been determined). The Washington Cascade zone, however, is old, whereas the Oregon Cascade zone appears to have been established only recently in response to anthropogenic habitat changes, which accounts for its low frequency of hybrids. We are unaware of any other replicate set of hybrid zones where differences in time since contact and dispersal have been related to variation in hybrid frequencies.El Tiempo Transcurrido desde el Contacto y el Flujo Genético Podrían Explicar la Variación en la Frecuencia de los Híbridos entre Tres Zonas de Hibridación entre Dendroica townsendi y D. occidentalis (Parulidae)
Guidelines for Using Double Sampling in Avian Population Monitoring
Authors: Collins Brian T. 
Published: September 2019

Abstract
Double sampling involves combining information from inexpensive rapid counts with intensive complete counts to provide an efficient population estimate. This technique is a valuable approach for calibrating population indices based on incomplete counts and improving the precision of monitoring studies. Data collected through a double-sampling protocol can be analyzed with either a ratio or a regression estimator. The ratio estimator is recommended when the relationship of the actual count to the rapid count is a straight line through origin, which may not be valid when surveying populations that have a small number of individuals per site and a low detection probability. In such situations, the regression estimator may be more appropriate. I investigated the properties of these two different estimators through a simulation study and tabulated sample sizes to control bias of the population average and standard error. Further, I used the results to evaluate when double sampling is a cost-effective design and how to design surveys that meet precision requirements. The design process is illustrated with the Spring Eastern Waterfowl Survey, which shows that double sampling is not always appropriate.
Directives pour l’utilisation de l’échantillonnage double dans le suivi des populations d’oiseaux
Local Annual Survival and Seasonal Residency Rates of Semipalmated Sandpipers (Calidris Pusilla) in Puerto Rico
Authors: Rice Susan M. , Collazo Jaime A. , Alldredge Mathew W. , Harrington Brian A. , Lewis Allen R. 
Published: September 2019

AbstractWe report seasonal residency and local annual survival rates of migratory Semipalmated Sandpipers (Calidris pusilla) at the Cabo Rojo salt flats, Puerto Rico. Residency rate (daily probability of remaining on the flats) was 0.991 ± 0.001 (x̄ ± SE), yielding a mean length of stay of 110 days. This finding supports the inclusion of the Caribbean as part of the species' winter range. Average estimated percentage of fat was low but increased throughout the season, which suggests that birds replenish some spent fat reserves and strive for energetic maintenance. Local annual survival rate was 0.62 ± 0.04, within the range of values reported for breeding populations at Manitoba and Alaska (0.53–0.76). The similarity was not unexpected because estimates were obtained annually but at opposite sites of their annual migratory movements. Birds captured at the salt flats appeared to be a mix of birds from various parts of the breeding range, judging from morphology (culmen's coefficient of variation = 9.1, n = 106). This suggested that origin (breeding area) of birds and their proportion in the data should be ascertained and accounted for in analyses to glean the full conservation implications of winter-based annual survival estimates. Those data are needed to unravel the possibility that individuals of distinct populations are affected by differential mortality factors across different migratory routes. Mean length of stay strongly suggested that habitat quality at the salt flats was high. Rainfall and tidal flow combine to increase food availability during fall. The salt flats dry up gradually toward late January, at the onset of the dry season. Semipalmated Sandpipers may move west to other Greater Antilles or south to sites such as coastal Surinam until the onset of spring migration. They are not an oversummering species at the salt flats. Conservation efforts in the Caribbean region require understanding the dynamics of this species throughout winter to protect essential habitat.Tasas de Supervivencia Anual Local y de Residencia Estacional de Calidris pusilla en Puerto Rico