bluuebunny/crossref_metadata_2025_split huggingface dataset:
New World Nine-Primaried Oscine Relationships: Constructing a Mitochondrial DNA Framework
Authors: Klicka John , Johnson Kevin P. , Lanyon Scott M. 
Published: September 2019

AbstractHistorically, a paucity of comparative morphological characters has led to much debate regarding relationships within and among the major lineages of New World nine-primaried oscines. More recently, DNA-DNA hybridization studies have provided novel and testable hypotheses of relationships, although no consensus has been reached. For 40 songbird taxa, we obtained 1,929 base pairs (bp) of DNA sequence from the mitochondrial cytochrome-b (894 bp) and NADH dehydrogenase subunit 2 (1,035 bp) genes. Phylogenetic analyses confirm the monophyly of this assemblage as traditionally defined. The lineages delineated historically on morphological grounds are retained; finches (Fringillinae) are sister to a well-supported clade (Emberizinae) containing blackbirds (Icterini), sparrows (Emberizini), wood-warblers (Parulini), tanagers (Thraupini), and cardinal-grosbeaks (Cardinalini). However, each tribe individually is either paraphyletic or polyphyletic with respect to most recent songbird classifications. Our results suggest that Euphonia is not a tanager but perhaps represents a derived form of cardueline finch. Piranga, traditionally considered a typical tanager, is a cardinaline in all of our analyses. Calcarius falls outside the sparrow lineage in all of our analyses, but its true affinities remain unclear. Elements of four different AOU families are represented in our clade Thraupini. The inclusion of several “tanager-finches” (Haplospiza, Diglossa, Tiaris, Volatinia, Sporophila) and a nectarivore (Coereba) in this clade is consistent with findings from other molecular phylogenies in suggesting that convergence in feeding specializations among some lineages has confounded traditional morphological classifications. We obtained a novel arrangement of relationships among tribes in our “best” topology; Cardinalini is sister to the rest of the Emberizinae assemblage (as defined by Sibley and Ahlquist [1990]), and Thraupini is sister to a clade containing Icterini, Emberizini, and Parulini. Despite nearly 2,000 bp of sequence for each taxon, and a high degree of stability across most weighting schemes and analytical methods, most nodes lack strong bootstrap support. The ND2 gene provided higher resolution than did cytochrome b, but combining genes provided the most highly supported and resolved topology. We consider the phylogeny a working hypothesis to be used as a guide for further studies within the nine-primaried oscine assemblage.
Brown-Headed Cowbird Parasitism Results in a Sink Population in Warbling Vireos
Authors: Ward David , Smith James N. M. 
Published: September 2019

Abstract
The Warbling Vireo (Vireo gilvus) is one of the most heavily parasitized host species of the Brown-headed Cowbird (Molothrus ater), suffering up to 80% parasitism in some areas. Warbling Vireo nests that are parasitized by cowbirds typically produce no vireo young. To make predictions about the consequences of brood parasitism on local host populations, we investigated factors that allow such high parasitism to occur. The major factors leading to high levels of brood parasitism on Warbling Vireos in the Okanagan Valley, British Columbia, are habitat overlap with cowbirds and the lack of response of vireos to cowbird eggs. Warbling Vireos responded more strongly to a cowbird dummy placed near the nest than to a dummy of a “neutral” species (junco) or to a common nest predator (crow). Preliminary simulation models based on population parameters obtained from three summers of fieldwork suggest that Warbling Vireos are in danger of extirpation from the Okanagan Valley if little movement of birds occurs between areas with different levels of brood parasitism. The models also indicate the sensitivity of this species to variation in adult and juvenile survival rates and number of successful broods produced per season. Our results emphasize the need for a metapopulation analysis that compares the population ecology of Warbling Vireos at high elevations (and probably with low parasitism) with that at low elevations (high parasitism) and that ascertains whether sufficient dispersal occurs between these populations to prevent extinction at lower elevations. Sufficient dispersal is indicated by apparently stable vireo populations in the Okanagan Valley and by Breeding Bird Survey data that show an overall increasing trend for this species in British Columbia.
Phylogenetic Relationships of Micronesian White-Eyes Based on Mitochondrial Sequence Data
Authors: Slikas Beth , Jones Isaac B. , Derrickson Scott R. , Fleischer Robert C. 
Published: September 2019

AbstractUsing mitochondrial sequence data, we estimated phylogenetic relationships and genetic divergence among selected species of white-eyes (Zosteropidae). We focused on taxa endemic to islands in Micronesia, specifically Zosterops conspicillatus, Z. semperi, Z. hypolais, Rukia oleaginea, and Cleptornis marchei. We also included in our data set five additional species of Zosterops from the Indo-Australian region and three species from Africa, as well as additional passerine outgroups. Our mitochondrial sequence data revealed substantial genetic divergence (5.7 to 7.3%) among Z. conspicillatus, Z. semperi, and Z. hypolais, three taxa that formerly were treated as a single species. In addition, a sequence divergence of 6.5 ± SE of 1.7% was found between the population of Z. conspicillatus from Rota and “conspecific” populations on Guam, Tinian, and Saipan. The distinctiveness of the Rota population suggests that this taxon should be recognized as a distinct species, a result that bears on the conservation of this population because it has been declining dramatically in recent years. All optimal trees based on analysis of the mitochondrial sequence data place Rukia oleaginea within the genus Zosterops. In all optimal trees, Cleptornis marchei positions as the sister taxon to a clade including all other zosteropids included in this study. The trees based on our data strongly contradict the traditional classification of Cleptornis as a honeyeater (family Meliphagidae). Our data cannot resolve with any confidence the sister relationships of the insular endemic white-eyes, although the optimal trees suggest multiple colonizations of Micronesia by more than one white-eye lineage.
Effects of Hematozoan Parasites on Condition and Return Rates of American Kestrels
Authors: Dawson Russell D. , Bortolotti Gary R. 
Published: September 2019

AbstractWe evaluated the relationship between blood parasites and body condition of American Kestrels (Falco sparverius) during the breeding season. Females that were infected with at least one species of parasite were in poorer condition than those without parasites during incubation but not prior to egg laying. We suggest that the relationship between parasitism and condition was masked before laying because of large increases in body mass of females during egg formation. Reduced condition of males during incubation also was associated with higher intensity of infections by Haemoproteus in one of two years. The negative association between condition and intensity of infection suggests that blood parasites impose costs on kestrels owing to competition for nutrients or allocation of energy by hosts to immune function or tissue repair. Alternatively, kestrels in poor condition may be more likely to have relapses of chronic infections, or they may be less able to control new infections because of resource limitations. In contrast to results during incubation, during the prelaying period the prevalence of parasites tended to be higher, and in one year infections were more intense, among males in good condition. One possible explanation for these results is that body condition of males during courtship is an important determinant of the quality of mate they are able to obtain, and males may be accumulating body reserves at the expense of decreased immune function. Return rates of female kestrels to the study area declined as the intensity of their Haemoproteus infections increased, suggesting that blood parasitism is associated with reduced survival or increased dispersal probability.
Does Vertical Partitioning of Nest Sites Decrease Nest Predation?
Authors: Reitsma Leonard R. , Whelan Christopher J. 
Published: September 2019

Abstract
Partitioning of nest heights among co-occurring species in response to nest predation has been proposed as a process that helps to structure avian species assemblages. In the experiment reported here, we used artificial nests baited with Japanese Quail (Coturnix japonica) eggs to test (1) whether both rate and final level of nest predation differed among nests placed at ground, shrub, and tree strata; and (2) whether vertical partitioning of nest sites among the three strata decreased nest predation. Although rates of nest predation increased from ground, to partitioned, to shrub, to tree strata, the only significant pairwise differences were between predation on ground nests versus all other treatments. The proportion of nests depredated at the conclusion of the experiment was lowest for the ground treatment, intermediate for the partitioned treatment, and highest for the shrub and tree treatments. Predation was significantly higher in 1988 than in 1989, and significant variation in predation occurred among five spatial replicates of the experimental treatments. Although the results show different susceptibilities to nest predation according to vegetative stratum, they show only a slight and nonsignificant reduction in nest predation as a consequence of vertical nest-site partitioning.
Morphometric Variation as an Indicator of Genetic Interactions Between Black-Capped and Carolina Chickadees at a Contact Zone in the Appalachian Mountains
Authors: Sattler Gene D. , Braun Michael J. 
Published: September 2019

AbstractWe studied hybridization and introgression between Black-capped (Poecile atricapillus) and Carolina (P. carolinensis) chickadees along two transects in the Appalachians using four genetic markers and multivariate analysis of morphology. Genetic data revealed that at least 58% of the birds in the center of each transect were of mixed ancestry and that recombinant genotypes predominated among hybrids, demonstrating that hybridization is frequent and that many hybrids are fertile. Genetic clines generally were steep and coincident in position, but introgression was evident well beyond the range interface. Introgression was higher at the one autosomal locus surveyed than in mitochondrial DNA or in two sex-linked markers, suggesting that the hybrid zone is a conduit for gene flow between the two forms at some loci. On a broad scale, morphometric variation was concordant with genetic variation. Clines in morphological variation based on principal components (PC) scores were steep and coincident with genetic clines. Also, a strong correlation within a population between PC scores and an individual's genetic makeup suggested that a large amount of morphological variation was genetically determined. However, morphological analysis indicated that hybrids were uncommon on one transect, whereas genetic data clearly showed that they were common on both. In addition, patterns of morphological variation were equivocal regarding introgression across the hybrid zone. Thus, genetic data provided a complementary and more detailed assessment of hybridization, largely due to the discrete nature of genetic variation. Genetic markers are useful in understanding hybridization and introgression, but diagnostic markers may underestimate average gene flow if selection against hybrids maintains steep clines at diagnostic loci. To gain a clearer picture of the genome-wide effects of hybridization, a much larger number of loci must be assayed, including non-diagnostic ones.
Direct and Indirect Estimates of Peregrine Falcon Population Size in Northern Eurasia
Authors: Quinn J. L. , Kokorev Y. 
Published: September 2019

Abstract
We used two different methods to estimate the density of nesting Peregrine Falcons (Falco peregrinus) across different parts of northern Eurasia. In the “territory-density” method, we extrapolated our density estimate of 406 km2 per territory (95% CI = 295 to 650 km2 per territory) in a high-density area, the Pyasina basin on the Taymyr Peninsula, to other similar areas across the range defined by published estimates. To estimate numbers in low-density areas, we used published data that suggested that Peregrine Falcon territories occur every 1,000 km2. Based on the nesting association between Peregrine Falcons and Red-breasted Geese (Branta ruficollis), we used a second, post hoc method to provide a comparative estimate where the ranges of the two species overlap. This model was based primarily on the population ecology of the Red-breasted Goose and included parameters such as the proportion of the goose population nesting with peregrines, the proportion of peregrine pairs associated with geese, goose population size, and three other variables. Some of these variables were already known, whereas others had been estimated as part of another study. The territory-density and nesting-association methods led to estimates of 1,586 (95% CI = 991 to 2,179) and 2,417 (95% CI = 1,306 to 3,528) falcon territories, respectively, across the common range of Peregrine Falcons and Red-breasted Geese; the first method suggested a population of 3,652 falcon territories (95% CI = 2,282 to 5,018) across the entire range F. p. calidus. Although both approaches entailed several major assumptions, together they provide the only quantitative estimate of this remote population of Peregrine Falcons.
Life in the Slow Lane: Reproductive Life History of the White-Browed Scrubwren, an Australian Endemic
Authors: Magrath Robert D. , Leedman Ashley W. , Gardner Janet L. , Giannasca Anthony , Nathan Anjeli C. , Yezerinac Stephen M. , Nicholls James A. 
Published: September 2019

AbstractAn understanding of geographic and phylogenetic variation in passerine life histories is hampered by the scarcity of studies from the Southern Hemisphere. We documented the breeding biology of the White-browed Scrubwren (Sericornis frontalis), an Australia endemic in the Pardalotidae (parvorder Corvida). Like other members of the Pardalotidae, scrubwrens had a long laying interval (two days), a long incubation period (declining from 21 to 17 days through the season), and a long period of postfledging parental care (6 to 7 weeks). Scrubwrens appeared to be typical of the Australian Corvida in having a small clutch size (three eggs) and a long breeding season (5.4 months), and they also had a long interval between breeding attempts (10 days after a failed attempt, 21 days after a successful attempt). Scrubwrens were multibrooded, often raising two broods successfully and occasionally raising three broods. The breeding biology of scrubwrens adds further support to claims of a distinct life-history strategy for members of the Corvida but also reinforces evidence that some “Corvida” life-history traits more specifically are those of the Pardalotidae.
A Striking New Species of Barbet (Capitoninae: Capito) From the Eastern Andes of Peru
Authors: O'Neill John P. , Lane Daniel F. , Kratter Andrew W. , Capparella Angelo P. , Joo Cecilia Fox 
Published: September 2019

AbstractIn 1996, an expedition of personnel from the Louisiana State University Museum of Natural Science and the Museo de Historia Natural de la Universidad Nacional Mayor de San Marcos made a trail from the east bank of the upper Río Cushabatay, departamento Ucayali, Peru, northeast to the top of a 1,538-m peak at 7°05′S, 75°39′W. The peak supports cloud forest from 1,200 m to the summit, and this “island” of habitat may be among the most isolated areas of cloud forest in South America. Among the depauperate cloud-forest avifauna we discovered a striking new species of Capito barbet, which apparently is the only member of the genus restricted to this habitat.
A Phenotypic Test of Haldane's Rule in an Avian Hybrid Zone
Authors: Smith Catherine E. , Rohwer Sievert 
Published: September 2019

AbstractWe introduce a phenotypic method to test for excess mortality in hybrids of the heterogametic sex, as expected from Haldane's rule, and apply this method to the unusually narrow hybrid zones between Hermit Warblers (Dendroica occidentalis) and Townsend's Warblers (D. townsendi) in the Pacific Northwest. Our test requires establishing comparable hybrid indices for male and female warblers. The hybrid index that we developed for females produced age-corrected distributions for phenotypically pure reference samples that closely matched those used by Rohwer and Wood (1998) for males. The similarity in these distributions enabled us to compare the relative frequency of males and females in hybrids and parentals. We detected no deficiency of hybrid females and thus no inviability in the heterogametic sex. Our failure to find evidence of the inviability component of Haldane's rule is not unexpected given the close relationship between these taxa; nonetheless, our methods should be generally useful for studies of hybrid zones.
Genetic Variation in The Endangered Southwestern Willow Flycatcher
Authors: Busch Joseph D. , Miller Mark P. , Paxton Eben H. , Sogge Mark K. , Keim Paul 
Published: September 2019

AbstractThe Southwestern Willow Flycatcher (Empidonax traillii extimus) is an endangered Neotropical migrant that breeds in isolated remnants of dense riparian habitat in the southwestern United States. We estimated genetic variation at 20 breeding sites of the Southwestern Willow Flycatcher (290 individuals) using 38 amplified fragment length polymorphisms (AFLPs). Our results suggest that considerable genetic diversity exists within the subspecies and within local breeding sites. Statistical analyses of genetic variation revealed only slight, although significant, differentiation among breeding sites (Mantel's r = 0.0705, P < 0.0005; θ = 0.0816, 95% CI = 0.0608 to 0.1034; ΦST = 0.0458, P < 0.001). UPGMA cluster analysis of the AFLP markers indicates that extensive gene flow has occurred among breeding sites. No one site stood out as being genetically unique or isolated. Therefore, the small level of genetic structure that we detected may not be biologically significant. Ongoing field studies are consistent with this conclusion. Of the banded birds that were resighted or recaptured in Arizona during the 1996 to 1998 breeding seasons, one-third moved between breeding sites and two-thirds were philopatric. Low differentiation may be the result of historically high rangewide diversity followed by recent geographic isolation of breeding sites, although observational data indicate that gene flow is a current phenomenon. Our data suggest that breeding groups of E. t. extimus act as a metapopulation.
Influence of Environmental and Density-Dependent Factors on Reproduction of Little Egrets
Authors: Bennetts Robert E. , Fasola Mauro , Hafner Heinz , Kayser Yves 
Published: September 2019

AbstractWe evaluated the influence of environmental and density-dependent factors (intraspecific and interspecific) on clutch size, brood size, and nesting success of Little Egrets (Egretta garzetta) in the Camargue of southern France. We recorded these reproductive parameters in most years from 1970 to 1998. We used a generalized linear modeling approach (model selection based on AIC) to examine the environmental effects of spring rainfall, winter temperature, and wind on these parameters. We also examined density dependence of these parameters based on the total number of Little Egrets and the total number of tree-nesting herons nesting in these mixed-species colonies. Clutch size was positively associated with rainfall and negatively associated with the number of Little Egret nests in the Camargue. Brood size was negatively associated with the number of Little Egret nests, although rainfall was only significant as an interaction effect with these two effects. Nesting success was negatively associated with the number of tree-nesting herons, the proportion of each colony consisting of Cattle Egrets (Bubulcus ibis), wind speed, and several interactions among these variables. Virtually all of the reproductive parameters that we evaluated were negatively associated with the number of Little Egret nests or the number of tree-nesting herons. Anecdotal evidence suggests that Cattle Egrets displace Little Egrets at some centrally located nest sites. Such sites are better protected from strong winds, which are a common cause of nesting failure.
Genetic Relationships of Cory's Shearwater: Parentage, Mating Assortment, and Geographic Differentiation Revealed by DNA Fingerprinting
Authors: Rabouam Corinne , Bretagnolle Vincent , Bigot Yves , Periquet Georges 
Published: September 2019

AbstractWe used DNA fingerprinting to assess genetic structure of populations in Cory's Shearwater (Calonectris diomedea). We analyzed mates and parent-offspring relationships, as well as the amount and distribution of genetic variation within and among populations, from the level of subcolony to subspecies. We found no evidence of extrapair fertilization, confirming that the genetic breeding system matches the social system that has been observed in the species. Mates were closely related, and the level of genetic relatedness within populations was within the range usually found in inbred populations. In contrast to previous studies based on allozymes and mtDNA polymorphism, DNA fingerprinting using microsatellites revealed consistent levels of genetic differentiation among populations. However, analyzing the two subspecies separately revealed that the pattern of genetic variation among populations did not support the model of isolation by distance. Natal dispersal, as well as historic and/or demographic events, probably contributed to shape the genetic structure of populations in the species.
Temporal and Age-Related Changes in Survival Rates of Southern Buller's Albatrosses (Thalassarche Bulleri Bulleri) at The Snares, New Zealand, 1948 to 1997
Authors: Sagar P. M. , Molloy J. , Weimerskirch H. , Warham J. 
Published: September 2019

AbstractWe estimated survival rates of adult Southern Buller's Albatrosses (Thalassarche bulleri bulleri) from 1948 to 1997 based on a long-term banding and recapture program at The Snares, New Zealand. Annual survival exceeded 0.95 from 1961 to 1968 and from 1992 to 1997 but declined to between 0.913 and 0.928 from 1969 to 1991. Reduced survival may have resulted from incidental mortality associated with longline and trawl fisheries in the foraging areas of these birds, but it must have been counterbalanced by changes in other population parameters because the population increased greatly in number from 1969 to 1997. Increased trawling activity in areas where albatrosses forage may have benefited the population by providing additional food, which may have enhanced the survival rate of recently fledged birds. We found no indication that survival rates differed between males and females, but an age effect occurred in which survival of birds with at least 25 years of breeding experience was lower than that of less-experienced and presumably younger birds.