bluuebunny/crossref_metadata_2025_split huggingface dataset:
Territoriality, Prospecting, and Dispersal in Cooperatively Breeding Micronesian Kingfishers (Todiramphus Cinnamominus Reichenbachii)
Authors: Kesler Dylan C. , Haig Susan M. 
Published: September 2019

AbstractWe investigated territoriality, prospecting, and dispersal behavior in cooperatively breeding Pohnpei Micronesian Kingfishers (Todiramphus cinnamominus reichenbachii) throughout the annual cycle using radiotelemetry and color-band resights. Mean home-range size was 6.3 ha and territories were 8.1 ha. Within territories, Micronesian Kingfishers shared 63% of their home-range space with coterritorial occupants, and 3% was shared with extraterritorial conspecifics. Birds on cooperative territories had larger home ranges that overlapped more with coterritory occupants' home ranges than birds in pair-held territories. Despite evidence suggesting that resources necessary for survival and reproduction occurred on each territory, Micronesian Kingfishers of all age and sex classes made extraterritorial prospecting movements. Prospecting was rare; it comprised only 4.3% of our observations. When birds departed on forays, they were gone for ∼1.9 h and returned to home territories before sunset. Prospecting by dominant birds was temporally correlated with courtship and nest initiation, and birds were observed at neighboring nest sites with opposite-sex conspecifics during the period when females were available for fertilization. Juveniles and helpers prospected throughout the year and made repeated homesteading movements to dispersal destinations before dispersing. Mean dispersal distance for radiomarked individuals was 849 m. Results suggest that prospecting in Micronesian Kingfishers is a complex behavior that provides information for dispersal decisions and familiarity with dispersal destinations. Additionally, extraterritorial movements may provide covert opportunities for reproduction, which have potential to profoundly influence the distribution of fitness among helper and dominant Micronesian Kingfishers.Territorialité, prospection et dispersion chez des Todiramphus cinnamominus reichenbachii présentant une reproduction coopérative
Ancestral State Reconstruction of Migration: Multistate Analysis Reveals Rapid Changes in New World Orioles (Icterus SPP)
Authors: Kondo Beatrice , Omland Kevin E. 
Published: September 2019

AbstractDuring the past century, numerous theoretical articles explored the evolution of seasonal migration in birds; many of these focused on environmental or social conditions that may have led to the origin of migration. More recent work has focused not on the origin of migration, but on changes in migratory behavior that have occurred in modern species and their immediate ancestors. We used a novel approach, a multistate ancestral state reconstruction of migration, to examine patterns of migratory evolution in the New World orioles (Icterus spp.). Both the multistate and binary reconstructions indicated repeated gains in migration. However, the multistate method revealed details of how migration may be gained that the standard binary-state reconstructions would not have shown. Our maximum-likelihood reconstruction, using branch lengths based on a molecular phylogeny, suggested multiple instances of rapid gain of migration. Furthermore, we found that every migratory species' migration type differed from that of its closest relatives. Surprisingly, no partially migratory species was closely related to a fully migratory species. These novel patterns involving gain of migration demonstrate the utility of multistate ancestral reconstruction for examining changes in migratory behavior in closely related birds.Reconstrucción de Estados Ancestrales de la Migración: Análisis con Múltiples Estados de Carácter Revelan Cambios Rápidos en los Orioles del Nuevo Mundo (Icterus spp.)
Environmental and Spatial Segregation of Leks Among Six Co-Occurring Species of Manakins (Pipridae) in Eastern Ecuador
Authors: Loiselle Bette A. , Blake John G. , Durães Renata , Ryder T. Brandt , Tori Wendy 
Published: September 2019

AbstractEnvironmental correlates and geographic spacing of leks were compared for six species of manakins (Pipridae) on two 100-ha study plots in eastern Ecuador. The “hotspot” hypothesis of lek evolution suggests that males should aggregate where females are most likely to be encountered. For ecologically similar species that co-occur at a site, leks are predicted to be clustered in space and, thus, to overlap in macroscale environmental characteristics. The geographic spacing and environmental characteristics of lek sites we observed were inconsistent with the hotspot hypothesis for lek evolution. In general, little geographic overlap occurred among leks, and geographic spacing of leks among heterospecifics more closely fit a regular than a clumped pattern. Further, environmental conditions of leks varied among species with respect to elevation and topography. Leks of some species were more likely to occur on hilltops or ridge tops (e.g., Machaeropterus regulus, Pipra erythrocephala), whereas others appeared to prefer highly dissected drainages (e.g., P. pipra), relatively flat terrain near streams (e.g., Chiroxiphia pareola), or seasonally inundated forests (e.g., P. filicauda). Using randomly placed leks, we found evidence that certain lek environments may be limited, which is consistent with observed levels of population abundances on the two plots. Such environmental limits may constrain lek placement and size. Further study is needed to determine the reproductive implications of placing leks in apparently suboptimal environments, though such compromises may reflect males making the best of a bad situation.Segregación Ambiental y Espacial de las Asambleas de Cortejo Entre Seis Especies Simpátricas de Saltarines (Pipridae) en el Oriente de Ecuador
Partitioning Risk Among Different Causes of Nest Failure
Authors: Etterson Matthew A. , Nagy Laura R. , Robinson Tara Rodden 
Published: September 2019

AbstractNest predation and nest parasitism receive the most attention as causes of nest failure for North American songbirds. Yet for many populations, interspecific competition, adverse weather, abandonment, nestling starvation, and egg failure may also be significant causes of nest failure. Despite the long interest in differential failure, serious challenges remain in the estimation of separate probabilities of nest failure from different causes. Apparent rates of failure suffer from at least two sources of bias: heterogeneous ages at discovery and classification error. We developed maximum-likelihood estimators for cause-specific daily probabilities of nest failure. We further show how the estimators can be extended to include classification error, if known. Finally, we demonstrate a simple application to Loggerhead Shrikes (Lanius ludovicianus), Tree Swallows (Tachycineta bicolor), Violet-green Swallows (T. thalassina), and Western Bluebirds (Sialia mexicana). Daily probabilities of survival were lower for the Loggherhead Shrike (0.978 ± 0.004) than for any of the three cavity-nesting species (range: 0.989 ± 0.002 − 0.993 ± 0.001). Weather was an important cause of nest failure for Loggerhead Shrikes (0.15 ± 0.05 overall). Conversely, competition among secondary cavity-nesters was not an important contributor to nest failure (range: 2–5% of nest failures) for bluebirds or swallows. Our estimator differs from others by allowing multiple fates to be modeled as separately estimated parameters rather than as covariates to a single estimated failure probability. Thus, our estimator should be viewed as an important complement to existing methods.División del Riesgo Entre Diferentes Causas de Fracaso Durante la Nidificación
Structure and Dynamics of The Hybrid Zone Between Black-Capped Chickadee (Poecile Atricapillus) and Carolina Chickadee (P. Carolinensis) in Southeastern Pennsylvania
Authors: Reudink Matthew W. , Mech Stephen G. , Mullen Sean P. , Curry Robert L. 
Published: September 2019

AbstractAnalysis of the structure and stability of a hybrid zone can serve as a starting point for examining mechanisms that influence spatial and evolutionary relationships between species. Recent studies of the hybrid zone between Black-capped Chickadee (Poecile atricapillus) and Carolina Chickadee (P. carolinensis) have suggested that genetic introgression is limited to a narrow zone, while also reinforcing the conclusion that the line of contact between these parapatrically distributed species is now shifting northward. We investigated the structure, position, and recent movement of the chickadee hybrid zone in southeastern Pennsylvania. Using selectively neutral microsatellite DNA markers, along with mitochondrial DNA haplotypes, we documented large differences in genetic composition among three populations ≤65 km apart where we sampled large numbers of breeding residents during 1998–2003. Genetic results indicate that the three sites support a population of Carolina Chickadees (Great Marsh), a population in which most individuals exhibit evidence of hybridization (Nolde Forest), and a population comprising mostly Black-capped Chickadees but with evidence of hybridization now taking place (Hawk Mountain). The patterns within the Nolde Forest population suggest that selection against hybrids may not be as strong as has been concluded from studies in other parts of the chickadee hybrid zone. Comparison of mitochondrial and nuclear genotypes between samples collected ≈15 years apart suggest that the northern edge of the hybrid zone shifted by ≈20 km over this interval, with hybridization now occurring as far north as the Kittatinny Ridge and beyond, where only Black-capped Chickadee genotypes were previously detectable. Our data and historical accounts suggest that the hybrid zone, now ≈50 km wide, may have become wider while also shifting northward. These results support the hypothesis that Carolina Chickadees enjoy a selective advantage during hybridization with Black-capped Chickadees, but both the proximate mechanisms and ultimate causes remain to be investigated.Structure et dynamique de la zone d'hybridation entre Poecile atricapillus et P. carolinensis dans le sud-est de la Pennsylvanie
Revision of Molt and Plumage Terminology in Ptarmigan (Phasianidae: Lagopus SPP.) Based on Evolutionary Considerations
Authors: Pyle Peter 
Published: September 2019

AbstractBy examining specimens of ptarmigan (Phasianidae: Lagopus spp.), I quantified three discrete periods of molt and three plumages for each sex, confirming the presence of a definitive presupplemental molt. A spring contour molt was significantly later and more extensive in females than in males, a summer contour molt was significantly earlier and more extensive in males than in females, and complete summer-fall wing and contour molts were statistically similar in timing between the sexes. Completeness of feather replacement, similarities between the sexes, and comparison of molts with those of related taxa indicate that the white winter plumage of ptarmigan should be considered the basic plumage, with shifts in hormonal and endocrinological cycles explaining differences in plumage coloration compared with those of other phasianids. Assignment of prealternate and presupplemental molts in ptarmigan necessitates the examination of molt evolution in Galloanseres. Using comparisons with Anserinae and Anatinae, I considered a novel interpretation: that molts in ptarmigan have evolved separately within each sex, and that the presupplemental and prealternate molts show sex-specific sequences within the definitive molt cycle.Revisión de la Terminología de la Muda y el Plumaje en Lagopus spp. (Phasianidae) con Base en Consideraciones Evolutivas
A Molecular Evaluation of the North American “Grassland” Sparrow Clade
Authors: Klicka John , Spellman Garth M. 
Published: September 2019

Abstract
Because they share several morphological and ecological characters, the North American sparrow (Emberizidae) genera Ammodramus, Passerculus, and Xenospiza have historically been considered members of a well-defined “grassland” sparrow assemblage. Relationships among the 11 members of this group have been the subject of much taxonomic debate, yet no comprehensive molecular assessment of relationships has been done. We investigated these relationships using mitochondrial DNA sequence data that included complete cytochrome-b and ND2 genes. Phylogenetic reconstructions derived via parsimony, likelihood, and Bayesian methods were congruent. The grassland sparrows, as presently configured, are polyphyletic. Pooecetes gramineus, Amphispiza belli (but not A. quinquestriata and A. bilineata), Oriturus superciliosus, and all three species of Melospiza are included in a reconfigured clade, whereas the traditional forms of Ammodramus savannarum, humeralis, and aurifons are placed well outside of these. Within the clade of interest, Ammodramus remains polyphyletic, with leconteii, maritimus, nelsoni, and caudacutus forming a well-resolved clade apart from henslowii and bairdii. The latter are in another strongly supported clade that also includes Passerculus and a Xenospiza-Melozpiza sister pairing. Pooecetes, Amphispiza (belli), and Oriturus represent early lineages in this clade that today have no close living relatives. The polyphyly of the genus Ammodramus is likely the result of morphological convergence attributable to similar adaptive responses to the occupation of similar habitats. In general, the morphological and ecological factors that have defined the grassland sparrows are poor indicators of relatedness. Taxonomic revisions are suggested.
Evaluación Molecular del Clado de Gorriones de Pastizales de Norte América
Molecular Systematics and Historical Biogeography of the Rock-Thrushes (Muscicapidae: Monticola)
Authors: Outlaw Robert K. , Voelker Gary , Outlaw Diana C. 
Published: September 2019

AbstractThe genus Monticola consists of 13 putative species with distributions throughout Eurasia and the sub-Saharan region of Africa. As such, this genus provides an excellent model with which to explore historical intercontinental movements and forces driving speciation in southern Africa. To address these questions, we reconstructed a hypothesis of species relationships using the mitochondrial ND2 and cytochrome-b genes. Monticola forms a well-supported, monophyletic clade within the avian family Muscicapidae. Our results support previous studies suggesting that the Malagasy genus Pseudocossyphus be subsumed into Monticola, and suggest that several of the Malagasy species (notably M. bensoni and M. erythronotus) are not valid. Sequence data, along with morphological and distributional evidence, support the elevation of M. pretoriae to species status. Historical biogeographic analyses suggest an area of origin for Monticola in the arid region of northern Africa plus Saudi Peninsula or the African savanna, or both. Determination of speciation timing suggests that Monticola arose ≈5.5 mya, with subsequent lineage splits occurring throughout the Pliocene and Pleistocene. We propose that climate-driven ecological vicariance as well as dispersal were important in the biogeographic history of this group and are responsible for present-day species relationships and distributions.Systématique moléculaire et biogéographie historique des monticoles (Muscicapidae: Monticola)
Population-Specific Demographic Estimates Provide Insights into Declines of Lark Buntings (Calamospiza Melanocorys)
Authors: Yackel Adams Amy A. , Skagen Susan K. , Savidge Julie A. 
Published: September 2019

Abstract
Many North American prairie bird populations have recently declined, and the causes of these declines remain largely unknown. To determine whether population limitation occurs during breeding, we evaluated the stability of a population of prairie birds using population-specific values for fecundity and postfledging survival. During 2001-2003, we radiomarked 67 female Lark Buntings (Calamospiza melanocorys) to determine annual fecundity and evaluate contributing factors such as nest survival and breeding response (number of breeding attempts and dispersal). Collectively, 67 females built 112 nests (1.67 ± 0.07 nests female−1 season−1; range: 1–3); 34 were second nests and 11 were third nests. Daily nest survival estimates were similar for initial and later nests with overall nest survival (DSR19) of 30.7% and 31.7%, respectively. Nest predation was the most common cause of failure (92%). Capture and radiomarking of females did not affect nest survival. Lark Bunting dispersal probabilities increased among females that fledged young from initial nests and females that lost their original nests late in the season. Conservative and liberal estimates of mean annual fecundity were 0.96 ±0.11 and 1.24 ± 0.09 female offspring per female, respectively. Given the fecundity and juvenile-survival estimates for this population, annual adult survival values of 71–77% are necessary to achieve a stable population. Because adult survival of prairie passerines ranges between 55% and 65%, this study area may not be capable of sustaining a stable population in the absence of immigration. We contrast our population assessment with one that assumes indirect values of fecundity and juvenile survival. To elucidate limiting factors, estimation of population-specific demographic parameters is desirable. We present an approach for selecting species and areas for evaluation of population stability.
Las Estimaciones Demográficas Poblacionales Específicas Brindan Pistas sobre la Disminución de Calamospiza melanocorys
Reproductive Strategies of Northern Geese: Why Wait?
Authors: Ely Craig R. , Bollinger Karen S. , Densmore Roseann V. , Rothe Thomas C. , Petrula Michael J. , Takekawa John Y. , Orthmeyer Dennis L. 
Published: September 2019

Abstract
Migration and reproductive strategies in waterbirds are tightly linked, with timing of arrival and onset of nesting having important consequences for reproductive success. Whether migratory waterbirds are capital or income breeders is predicated by their spring migration schedule, how long they are on breeding areas before nesting, and how adapted they are to exploiting early spring foods at northern breeding areas. However, for most species, we know little about individual migration schedules, arrival times, and duration of residence on breeding areas before nesting. To document these relationships in a northern nesting goose, we radiotracked winter-marked Tule Greater White-fronted Geese (Anser albifrons elgasi; hereafter “Tule Geese”; n = 116) from the time of their arrival in Alaska through nesting. Tule Geese arrived on coastal feeding areas in mid-April and moved to nesting locations a week later. They initiated nests 15 days (range: 6–24 days) after arrival, a period roughly equivalent to the duration of rapid follicle growth. Tule Geese that arrived the earliest were more likely to nest than geese that arrived later; early arrivals also spent more time on the breeding grounds and nested earlier than geese that arrived later. The length of the prenesting period was comparable to that of other populations of this species, but longer than for goose species that initiate rapid follicle growth before arrival on the breeding grounds. We suggest that Tule Geese nesting in more temperate climates are more likely to delay breeding to exploit local food resources than Arctic-nesting species that may be constrained by short growing seasons.
Estrategias Reproductivas de los Gansos del Norte: ¿Por Qué Esperar?
Evolution of Coloniality in Birds: A Test of Hypotheses With the Red-Necked Grebe (Podiceps Grisegena)
Authors: Sachs Joel L. , Hughes Colin R. , Nuechterlein Gary L. , Buitron Deborah 
Published: September 2019

Abstract
Group breeding is perplexing, because individuals incur density-dependent fitness costs to breed in groups, yet no universal benefit appears to explain its evolution. Coloniality in birds, defined as dense nesting within limited territories, is a striking example of group breeding. Adaptive explanations for coloniality are diverse, and several research approaches have emerged. Here, we test models for the evolution of coloniality with a population of Red-necked Grebes (Podiceps grisegena). We distinguish habitat models from conspecific models for explaining the adaptive evolution of coloniality. Habitat models propose that the fitness benefits of colonial breeding are gained through the characteristics or location of the colony site, whereas conspecific models posit that the benefits of colonial breeding are gained solely from nesting near conspecifics. Red-necked Grebes are waterbirds that typically nest in a dispersed fashion, only rarely nesting in colonies. Both dispersed and colonial nesting co-occurred in the study population, and aquatic nests were found in three distinct habitat types. We gathered detailed demographic data and used analyses of covariance to test whether variation in habitat type or conspecific aggregation best explained differences in breeding success across the population. We further used fitness, genetic, and spatial data to test whether kin selection, sexual selection, or conspecific reproductive-success cueing may drive colony formation. The data provided strong support for a habitat-based model and inconsistently supported conspecific models. Our results suggest that colonial individuals of this population gain selfish benefits from relatively rare, high-quality habitat rather than from proximity of conspecifics.
Evolución de la Colonialidad en las Aves: Una Evaluación de las Hipótesis en Podiceps grisegena
Seasonal Egg-Mass Variation and Laying Sequence in a Bird With Facultative Brood Reduction
Authors: D'Alba Liliana , Torres Roxana 
Published: September 2019

AbstractFemales may maximize their lifetime reproductive output by adjusting their investment in each breeding event to the perceived likelihood of success. The Blue-footed Booby (Sula nebouxii) is a long-lived seabird with facultative siblicide. We examined whether there is differential resource allocation to eggs with laying order and whether greater egg mass increases hatching probability, chick survival, hatching interval, and mass and size at hatching. We found that the relative investment in first and second eggs decreased as the season advanced: second eggs were slightly (1.5%) heavier than first eggs in early clutches; by contrast, first eggs were 2% heavier than second eggs in late clutches. Accordingly, hatching probability increased with laying date for first eggs and decreased for second eggs. The mass of the egg increased hatching probability, and no effect on chick survival was detected. Laying interval increased after a heavier egg was laid, and heavier eggs produced heavier hatchlings. Hatching intervals were positively related to laying intervals, but egg mass was unrelated to the length of the incubation period and the hatching interval. Our results suggest that egg mass influences embryo survival and that Blue-footed Booby females may adaptively allocate resources to eggs of different laying order according to breeding conditions.Variación del Peso de los Huevos y Secuencia de Postura en un Ave con Reducción Facultativa de la Nidada