bluuebunny/crossref_metadata_2025 huggingface dataset:
A New Species of Akalat (Sheppardia) Narrowly Endemic in the Eastern Arc of Tanzania
Authors: Beresford Pamela , Fjeldså Jon , Kiure Jacob
Published: September 2019

The group of small forest robins, or akalats, that dwell in lowland and montane forests in Africa have complicated parapatric or partly overlapping distributions, the details of which are still being discovered. Here, we use external morphology and mitochondrial and nuclear DNA sequence data to determine the reciprocal monophyly of several populations, including one form that is related to Sheppardia lowei and S. montana. Those data corroborate the recognition of a new species, Sheppardia aurantiithorax, and show relatively high levels of sequence divergence among populations of the different species. The discovery of this new species, narrowly endemic in the Eastern Arc montane forests, emphasizes the complex biodiversity of the region and underscores the need for prompt and effective conservation measures.
Phylogenetic Relationships Among Some Neotropical Parrot Genera (Psittacidae) Based on Mitochondrial Sequences
Authors: Tavares Erika S. , Yamashita Carlos , Miyaki Cristina Y.
Published: September 2019

The New World tribe Arini includes 30 genera and represents 148 known species of parrots. A previous phylogenetic study examined nine of those genera and suggested the existence of two groups. Our objective was to better understand the relationships among 14 species from 9 genera belonging to one of those groups. We partially sequenced the 12S and 16S ribosomal DNAs, cytochrome b, cytochrome oxidase I, and control region. We improved our understanding of the phylogenetic relationships among Neotropical parrots by adding both taxa and sequences, but the relationships among the deeper lineages were not well resolved. Our results agree with present classifications that place some species formerly in the genus Ara into three additional genera (Primolius, Orthopsittaca, and Diopsittaca). Additionally, we suggest that (1) D. nobilis and Guarouba guarouba are closely related and the genus Aratinga is not monophyletic; (2) diversification of genera may have occurred during the Miocene, and of species within genera during the Pliocene and Pleistocene; and (3) geologic, climatic, and environmental changes in South America may have been related to that diversification.
Is Monogamy in the Polynesian Megapode (Megapodius Pritchardii) Related to its High Relative Egg-Weight?
Authors: Göth Ann , Vogel Uwe
Published: September 2019

Parental care is regarded as one of the most influential forces acting on the evolution of mating systems. Polynesian Megapodes (Megapodius pritchardii) are burrow nesters and rely on geothermal heat for incubation. Because they provide no parental care, either before or after hatching, they can provide insights into selective forces that have shaped mating systems in the absence of parental care. Our study of their mating system—the first such study of any burrow-nesting megapode—suggests social monogamy. The partners of 10 marked pairs stayed together in the same territory for ≤12 months and were seen with their partner significantly more often than on their own. In 64% of all observations, pair partners foraged <5 m apart, and females fed on food items uncovered by the male. Duets also indicated long-lasting pair bonds. We propose that monogamy in this species is related to the fact that females lay only one large egg at a time (which weighs, on average, 24% of her body weight), in intervals of several days or weeks. Producing eggs year-round, females require a high intake of protein-rich food. They seem to benefit, within the pair bond, from the male-defended feeding territory and from the invertebrates the male uncovers while feeding close by. While being guarded by the male, females can spend more time searching for food and are protected from forced copulations by other males. The monogamous pair bond seems to benefit the male by enhancing his chances of fertilizing his partner's eggs; with an unpredictable laying interval and year-round egg production, males cannot predict when their partner will be fertile and thus benefit from staying with her year-round.
Use of Body Stores in Shorebirds After Arrival on High-Arctic Breeding Grounds
Authors: Morrison R. I Guy , Hobson Keith A.
Published: September 2019

Stable-isotope analyses of egg components can illuminate the contributions of endogenous and exogenous nutrients to egg formation in cases where birds move from one isotopic biome to another just before egg-laying, as in Red Knots (Calidris canutus islandica) and Ruddy Turnstones (Arenaria interpres interpres) nesting in the northeastern Canadian High Arctic. Those populations use inshore marine habitats during the winter and northward migration periods, but switch to feeding and breeding in terrestrial C-3 habitats in the Arctic. Upon the birds' arrival at Alert, Nunavut, Canada, stable carbon (δ13C) and nitrogen (δ15N) isotope values for their red blood cells were consistent with those expected from an inshore marine diet. After the birds switched to a terrestrial diet, those values decayed in a negative exponential fashion until they reached asymptotic values consistent with a local terrestrial C-3 diet. Components of eggs laid later in the season, including lipid-free yolk, albumen, yolk lipid, and albumen lipid, generally showed isotope values consistent with routing from exogenous (i.e. local) nutrient sources, which supports the notion that High Arctic shorebirds are primarily income and not capital breeders. However, eggs in earliest clutches were enriched in 13C and 15N, which suggests that some residual marine nutrients were available for reproduction. The extent to which endogenous stores are transferred to eggs in High Arctic shorebirds may depend on year and climatic conditions.
Flushing, Capture, and Bleeding do not Affect Return Rate of Female Wood Thrushes (Hylocichla Mustelina) in Delaware
Authors: Perkins Kelly A. , Roth Roland R. , Bowman Jacob L. , Green Jordan
Published: September 2019

Theoretical questions and conservation concerns have prompted numerous, intensive studies of songbird nesting ecology. Such studies use several techniques (flushing, capture, and blood sampling) that have the potential to negatively affect reproduction, survival, and site fidelity. Although studies have examined the effects of those techniques on avian reproduction and survival, the effect on the return rate of breeding songbirds has not been researched. We used data from a 28-year demographic study to investigate the possible effect of those three common research practices on the return rate of female Wood Thrushes (Hylocichla mustelina). We also tested reproductive success and age as predictors of return because they have been shown to influence site fidelity. Number of successful nests in a breeding season was the variable that best predicted return the following year. None of the research practices negatively affected return rate. That pattern held even among yearlings with zero production, a group that should be the most easily disturbed. We also show that using all years of return for site-faithful birds as observations (i.e. repeated sampling) inflates the estimated return rate.
Territory Switching and Floating in White-Bellied Antbird (Myrmeciza Longipes), A Resident Tropical Passerine in Panama
Authors: Fedy Bradley C. , Stutchbury Bridget J. M.
Published: September 2019

We investigated the yearlong territorial behavior of White-bellied Antbirds (Myrmeciza longipes) in Panama by conducting 17 experimental removals during the nonbreeding season on both sexes. We also monitored the territorial behavior and occupancy of 48 males and 34 females throughout the nonbreeding and breeding seasons. We tested the importance of territory switching, mate advertisement, foray behavior, and role of floaters. In seven of the removal experiments, both members of a pair were radiotagged and tracked throughout the duration of the experiments. It was predicted that widowed birds would attempt to attract a new mate through increased song rate or unique vocalizations; however, that behavior was not observed in White-bellied Antbirds. We documented a weak response in floaters to territorial vacancies and found that territory switching occurs regularly in response to experimental removals and naturally within populations. We found density of birds in an area influences the probability of replacement and is likely a reflection of territory quality given that birds in high-density areas were in better physical condition, spent less time off-territory, and competed more for those territories. Telemetry revealed that individuals made silent extraterritorial forays during the nonbreeding season. Birds could use those forays to assess the quality and status of neighboring territories and to find food during this period when food abundance is low. Several birds were observed to temporarily abandon territorial behavior for periods from 2 to 13 months, a previously undocumented behavior in this type of territorial system.
How do Woodpeckers Extract Grubs With Their Tongues? A Study of The Guadeloupe Woodpecker (Melanerpes Herminieri) in The French West Indies
Authors: Villard Pascal , Cuisin Jacques
Published: September 2019

We held an adult Guadeloupe Woodpecker (Melanerpes herminieri) in captivity for two weeks and documented its tongue movements as it caught grubs placed into holes that had been excavated out of a log. We provide evidence that the Guadeloupe Woodpecker does not spear grubs with its tongue but instead grabs them with the tongue's horny tip, which is barbed and coated with saliva, and pulls them out of the holes.
Structure of an African Red-Billed Hornbill (Tockus Erythrorhynchus Rufirostris and T. E. Damarensis) Hybrid Zone as Revealed by Morphology, Behavior, and Breeding Biology
Authors: Delport Wayne , Kemp Alan C. , Ferguson J. Willem H.
Published: September 2019

The distributions of southern African (Tockus erythrorhynchus rufirostris) and Damaraland (T. e. damarensis) Red-billed Hornbills overlap in northern Namibia. Allopatric populations of the taxa have diagnosable differences in habitat, morphology, vocalizations, and displays. We investigated the structure of the hybrid zone using data from morphology, behavior, and breeding biology. The morphological characteristics—eye color and facial plumage color—were summarized as hybrid index scores, which showed a significant positive regression against distance from southwest to northeast across the hybrid zone. Vocalizations also showed a positive relationship between the first principal component (extracted from 12 call variables) and distance across the hybrid zone. However, there appears to be introgression of a T. e. damarensis call into T. e. rufirostris, but not vice versa. In addition, female T. e. damarensis-male T. e. rufirostris breeding pairs occur more frequently than male T. e. damarensis-female T. e. rufirostris pairs. The asymmetrical call introgression may result either from asymmetry in mating or from genetic control of call inheritance. Finally, heterospecific pairs show lower fitness, in the form of reduced hatching success, even when female fitness attributes are included as covariates. Although we are uncertain whether the Red-billed Hornbill hybrid zone is stable, the apparent biological processes operating within it conform to predictions of both the “mosaic” and the “tension zone” models, because both habitat characteristics and a balance of dispersal and selection appear to determine its structure.
Nutrient Reserves of Lesser Scaup (Aythya Affinis) During Spring Migration in the Mississippi Flyway: A Test of the Spring Condition Hypothesis
Authors: Anteau Michael J. , Afton Alan D.
Published: September 2019

The continental scaup population (Lesser [Aythya affinis] and Greater [A. marila] combined) has declined markedly since 1978. One hypothesis for the population decline states that reproductive success has decreased because female scaup are arriving on breeding areas in poorer body condition than they did historically (i.e. spring condition hypothesis). We tested one aspect of that hypothesis by comparing body mass and nutrient reserves (lipid, protein, and mineral) of Lesser Scaup at four locations (Louisiana, Illinois, Minnesota, and Manitoba) between the 1980s and 2000s. We found that mean body mass and lipid and mineral reserves of females were 80.0, 52.5, and 3.0 g higher, respectively, in the 2000s than in the 1980s in Louisiana; similarly, body mass and lipid and mineral reserves of males were 108.8, 72.5, and 2.5 g higher, respectively. In Illinois, mean body mass and lipid reserves of females were 88.6 and 56.5 g higher, respectively, in the 2000s than in the 1980s; similarly, body mass and lipid and mineral reserves of males were 80.6, 76.0, and 2.7 g higher, respectively. Mean body mass of females were 58.5 and 58.9 g lower in the 2000s than in the 1980s in Minnesota and Manitoba, respectively; mean body mass of males, similarly, were 40.7 g lower in Minnesota. Mean lipid reserves of females in the 2000s were 28.8 and 27.8 g lower than those in the 1980s in Minnesota and Manitoba, respectively. Mean mineral reserves of females in the 2000s were 3.2 g lower than those in the 1980s in Manitoba. Consequently, females arriving to breed in Manitoba in the 2000s had accumulated lipid reserves for 4.1 fewer eggs and mineral reserves for 0.8 fewer eggs than those arriving to breed there in the 1980s. Accordingly, our results are consistent with the spring condition hypothesis and suggest that female body condition has declined, as reflected by decreases in body mass, lipids, and mineral reserves that could cause reductions in reproductive success and ultimately a population decline.
The American Bird Conservancy Guide to the 500 Most Important Bird Areas in the United States
Authors: Cooper Robert J. , Warnell Daniel B.
Published: September 2019

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.
Miocene Songbirds and the Composition of the European Passeriform Avifauna
Authors: Manegold Albrecht , Mayr Gerald , Mourer-Chauviré Cécile
Published: September 2019

Songbirds (Passeriformes) occur in the fossil record of the Northern Hemisphere around the early Oligocene. It has recently been suggested that the major passeriform lineages diverged in Gondwana in the mid- to late Cretaceous and that the oscines, which include all extant European songbirds, originated on the Australian continental plate. Suboscines are assumed to have originated in western Gondwana. Although there is an abundant fossil record of songbirds in Europe, few attempts have been made to set those remains in a phylogenetic context. Our examination of fossil songbirds from three middle Miocene localities in Germany and France shows that many lack the derived morphology of the hypotarsus that characterizes extant Eupasseres (a taxon that comprises oscines and suboscines). We assume that these fossil taxa are outside the crown-group of Eupasseres, which indicates the presence of an ancient songbird avifauna in the Miocene of Europe, in addition to the few fossil Eupasseres already described in the literature.
Individual Risk Versus Immediate Reproductive Success: A Basis for Latitudinal Differences in the Adrenocortical Response to Stress in Yellow Warblers (Dendroica Petechia)
Authors: Wilson C. Morgan , Holberton Rebecca L.
Published: September 2019

In many bird species, Arctic-breeding and temperate-zone-breeding populations may have different behavioral and physiological adaptations that reflect trade-offs between immediate survival and reproductive success. Compared with their temperate-zonebreeding counterparts, Arctic breeders face shorter breeding seasons and less predictable environments. As a result, it may be necessary for Arctic breeders to employ immediate life-saving responses (facilitated through an acute adrenocortical response) that might come at the expense of immediate reproductive success. Regardless of latitude, the sexes may also face differences in the trade-off between immediate survivorship and reproductive effort. To investigate those hypotheses, we (1) measured the adrenocortical response of male and female Yellow Warblers (Dendroica petechia) at both ends of a north-south breeding distribution and (2) examined within- and between-sex variation in corticosterone secretion during distinct stages of the breeding season that represent significant differences in parental investment (e.g. incubation and nestling provisioning). As predicted, Arctic-breeding males showed a significantly reduced adrenocortical response during the nestling period (when their parental contribution was highest; mean reduction = 39%), whereas temperate-zone-breeding males showed no significant reduction (mean reduction = 12%). Arctic-breeding and temperate-zone-breeding females did not differ in their adrenocortical responses during incubation and provisioning stages, showed reduced responses when compared with temperate-zone-breeding males, and showed responses similar to those of Arctic-breeding males during the provisioning stage. These data support the hypothesis that, during the breeding season, a reduced adrenocortical response (1) is more likely to occur when the potential for brood loss is greatest and (2) is associated with the degree of parental investment by the sexes. The balance between cost(s) and benefit(s) of the adrenocortical response may vary with the relative risks to survivorship and breeding success, and may vary between populations facing different time and energy constraints.
Bactericidal and Fungicidal Activity of Ant Chemicals on Feather Parasites: An Evaluation of Anting Behavior as a Method of Self-Medication in Songbirds
Authors: Revis Hannah C. , Waller Deborah A.
Published: September 2019

Songbirds apply ants to their feathers during anting behavior, possibly as a method of reducing feather parasites. We tested polar and nonpolar ant secretions and pure formic acid for bactericidal and fungicidal effects on microbial ectoparasites of feathers. Microbial inhibition trials were run with the bacteria Bacillus licheniformis (strains OWU 138B and OWU 1432B) and B. subtilis; and with the fungi Chaetomium globosum, Penicillium chrysogenum, and Trichoderma viride. Ant chemicals were derived from Camponotus pennsylvanicus, Pheidole dentata, Aphaenogaster rudis, Crematogaster lineolata, and Lasius flavus worker-caste ants. Although pure formic acid strongly inhibited all bacteria and fungal hyphae tested, concentrations of formic acid found in the bodies of formicine ants did not. Neither hexane ant-chemical extracts nor ant suspensions in deionized water inhibited the microbial species. Consequently, the hypothesis that birds apply ants to control feather parasites was not supported.
The Speciation and Biogeography of Birds
Authors: Zink Robert M. , Jones Andrew W.
Published: September 2019

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.
Birds of Thailand
Authors: Gale George A.
Published: September 2019

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.
Eighteenth-Century Naturalists of Hudson Bay
Authors: Cooke Fred
Published: September 2019

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.
Feeding Ecology of Canada Geese (Branta Canadensis Interior) in Sub-Arctic Inland Tundra During Brood-Rearing
Authors: Cadieux Marie-Christine , Gauthier Gilles , Hughes R. John
Published: September 2019

The diet of adult Canada Geese (Branta canadensis interior) and their goslings was determined during the brood-rearing season in a freshwater tundra habitat using esophageal contents from 25 adult females, 27 adult males, and 59 goslings. Habitat use by geese and the availability and quality of aboveground biomass in wet sedge meadows and around ponds in lichen-heath tundra were also evaluated throughout the summer. During the first four weeks of brood-rearing, adult Canada Geese ate primarily graminoids (>65%), especially leaves of the short form of Carex aquatilis and Eriophorum spp., which had the highest nitrogen concentration (2.5–3.5%). Although graminoids were also important for goslings, they consumed a greater variety of other plant species (68%) than adults, especially in the first two weeks, possibly because of their inexperience. Late in the brood-rearing period, as the nitrogen concentration of graminoid plants declined, adults shifted to a diet composed mainly of berries (>40%, mostly Empetrum nigrum). At that time, goslings consumed fewer berries (24%) and maintained a higher proportion of nitrogen-rich plants in their diet (53% leaves, mostly graminoids) than adults, presumably to complete their growth. Plant species consumed by geese over the summer indicated a preference for high-quality plants (i.e. those with a high nitrogen concentration). Consequently, wet sedge meadow, the habitat that offered plant species of highest quality, was the habitat most heavily used throughout the summer, particularly around peak hatch. Goose grazing had no effect on seasonal production of aboveground biomass of graminoids, probably because of the relatively low density of the goose population.

Écologie alimentaire de Branta canadensis interior pendant la période d’élevage des jeunes dans un milieu d’eau douce sub-arctique
Acoustic Properties of Two Urban Song Dialects in the Orange-Tufted Sunbird (Nectarinia Osea)
Authors: Leader Noam , Wright Jonathan , Yom-Yov Yoram
Published: September 2019

Biologically important acoustic signals must be transmitted from a signaler to a receiver. Over distance, however, sounds may undergo modification through attenuation, degradation, and masking. Recent anthropogenic habitat modification occurring in many places—in urban habitats, in particular—has rapidly changed local topography and atmospheric conditions and generated new patterns of noise that are likely to interfere with communicative signals. As part of a study of microgeographic song dialects in an urban population of Orange-tufted Sunbirds (Nectarinia osea) in Israel, we examined the environmental influences on song transmission and reception in a rapidly developing human-altered environment. We examined the physical properties of the two dialect song types, which exhibit a large difference of 2–3 kHz in the maximum frequency of the trill, using sound transmission measurements to test how both song types propagate through a highly obstructed habitat of buildings and vegetation. Additionally, we examined how ambient noise—in particular, low-frequency noise arising mainly from automobile traffic—affects the transmission of both dialect songs. Finally, using song playback, we investigated the consequences of sound degradation on dialect recognition and discrimination by sunbirds. The dialect containing higher frequencies in the trill was found to undergo severe frequency-dependent attenuation, in which the maximum frequency of the trill notes drops by >2 kHz over a distance of 70–100 m (less than two territories away). Also, the possibility that the use of higher frequencies in that dialect group's song is intended to overcome masking by urban ambient noise, which is concentrated mainly in lower frequencies, was not supported by our findings. Males singing the high dialect responded differently to playbacks of an intact and an attenuated form of their dialect song. Taken together, our results suggest that the dialect containing higher frequencies in the trill may be unsuitable for effective long-range transmission through this particular sunbird habitat.

Propiedades Acústicas de Dos Dialectos del Canto Urbano de Nectarinia osea
Calcium Availability Limits Reproductive Output of Tree Swallows (Tachycineta Bicolor) in a Nonacidified Landscape
Authors: Bidwell Mark T. , Dawson Russell D.
Published: September 2019

Breeding birds require high levels of energy and certain nutrients, such as calcium. The extent to which calcium limits reproduction in wild birds is unclear. We performed a supplementation experiment to determine whether calcium limits the reproductive output of free-ranging insectivorous Tree Swallows (Tachycineta bicolor), a species whose usual diet contains little calcium. Providing supplemental calcium in the form of crushed oyster shell did not affect clutch initiation date, but it caused birds that had not started constructing a nest when we first detected them on the study area to begin laying sooner, which suggests that calcium reduced the length of the prelaying period. Supplemented females produced larger eggs, and that effect was most pronounced among females in good body condition. There was a trend for supplemented birds to produce larger clutches, and their clutches had significantly greater total mass than those of control birds. Supplemented birds, in particular those breeding late in the season, also hatched significantly more eggs. Our results suggest that calcium availability may limit some aspects of avian reproduction, even in nonacidified landscapes like our study area, where levels of calcium in the soil are high.

La Disponibilidad de Calcio Limita el Rendimiento Reproductivo de Tachycineta bicolor en un Paisaje no Acidificado
A New Species of Aratinga Parakeet (Psittaciformes: Psittacidae) from Brazil, With Taxonomic Remarks on the Aratinga Solstitialis Complex
Authors: Silveira Luís Fábio , Thadeo de Lima Flávio César , Höfling Elizabeth
Published: September 2019

We describe a new species of Aratinga—A. pintoi (Sulfur-breasted Parakeet)—from open areas on the northern bank of the lower Amazon River in the state of Pará, Brazil. It was for a long time misidentified as a juvenile of A. solstitialis or a hybrid between that species and A. jandaya. It can be distinguished from other Aratinga species by the combination of the following characters: mantle and wing coverts green, suffused with pale yellow; underparts pale yellow, with pale orange restricted to belly and flanks; and feathers on the underparts with a dark rachis. On the basis of color characters and general morphology, we suggest that this new species should be a member of a group composed of A. solstitialis, A. jandaya, A. auricapillus, and, possibly, Nandayus nenday. A review of taxonomy and distribution of the group is also presented.

Uma nova espécie de Aratinga (Psittaciformes: Psittacidae) do Brasil, com comentários sobre a taxonomia do complexo de espécies Aratinga solstitialis
Body Mass of Long-Tailed Ducks (Clangula Hyemalis) During Incubation
Authors: Kellett Dana K. , Alisauskas Ray T. , Mehl Katherine R. , Drake Kiel L. , Traylor Joshua J. , Lawson Shona L.
Published: September 2019

We investigated body-mass dynamics during incubation of Long-tailed Ducks (Clangula hyemalis) nesting in Canada’s central Arctic, 1998–2003. Long-tailed Duck females (n = 37) lost 7% of pre-incubation body mass during incubation; on average, females weighed 618 ± 15 g (mean ± SE) at clutch completion and 575 ± 11 g at hatch. Given the differences in body size, Long-tailed Ducks relied less on endogenous reserves than sympatric King Eiders (Somateria spectabilis), but lost less mass than similar-sized waterfowl species nesting in temperate climates. Preliminary data suggest that Long-tailed Ducks maintain similar or higher nest-attendance rates than temperate-nesting waterfowl of similar size, and we suggest that access to locally abundant, high-quality foods enable Long-tailed Duck females to maintain high incubation constancy without sacrificing female body condition. Nevertheless, Long-tailed Ducks appear to differ widely from most Arctic-nesting waterfowl in nutritional strategy for nesting.

Masse corporelle chez l’Harelde kakawi (Clangula hyemalis) au cours de l’incubation
Multiple-Day Constancy as an Alternative to Pooling for Estimating Mark-Recapture Stopover Length in Nearctic-Neotropical Migrant Landbirds
Authors: Morris Sara R. , Liebner David A. , Larracuente Amanda M. , Escamilla Erica M. , Sheets H. David
Published: September 2019

Capture-mark-recapture models require estimation of parameters that may be either constant or time-dependent. Open-population models have been adapted for use in estimating stopover duration of migratory songbirds. However, with data collected over an extended period or with relatively few recaptures, small sample sizes may preclude use of fully time-dependent models. Pooling is commonly used to reduce the number of parameters estimated in time-dependent models. In pooling, all captures and recaptures during a specified interval are treated as a single capture event, which results in a loss of information about recaptures within the interval. Additionally, pooling of banding data of migratory songbirds appears to bias stopover-length estimates upwards. An alternative to pooling is use of multiple-day-constancy models. Advantages of this approach include maintenance of all recapture data, simultaneous Akaike’s Information Criterion-based comparison of models using different constancy intervals, and unbiased stopover estimates.

Constancia de Múltiples Días como una Alternativa a la Combinación de Datos de Captura-Recaptura para Estimar la Duración de las Paradas de Aves Migrantes Neárticas-Neotropicales Terrestres
Mark–Recapture and DNA Fingerprinting Data Reveal High Breeding-Site Fidelity, Low Natal Philopatry, and Low Levels of Genetic Population Differentiation in Flammulated Owls (Otus Flammeolus)
Authors: Arsenault David P. , Stacey Peter B. , Hoelzer Guy A.
Published: September 2019

Over a seven-year period, we used mark-recapture in a population of Flammulated Owls (Otus flammeolus) in the Zuni Mountains, New Mexico, to estimate adult breeding-site fidelity, mate fidelity, natal philopatry, and dispersal distances. We also used DNA fingerprinting to examine the genetic population structure of Flammulated Owls among four mountain ranges in New Mexico and one range in Utah. Mark-recapture revealed that adults are site-faithful and tend to maintain pair bonds between years, whereas juveniles show little natal philopatry. DNA fingerprinting revealed very low differentiation among populations, even between the New Mexico and Utah ranges, with population subdivision (FST) estimates ranging from 0.00 to 0.04. Heterozygosity values were high within each mountain range and, together with the low FST values, suggest that this Neotropical migrant may have long-distance natal dispersal and frequent intermountain dispersal.

Datos de Marcado-Recaptura y Huellas Dactilares de ADN Revelan Alta Fidelidad a los Sitios de Cría, Baja Filopatría Natal y Bajos Niveles de Diferenciación Genética Poblacional en Otus flammeolus
More Than Kin and Less Than Kind: The Evolution of Family Conflict
Authors: Mumme Ronald L.
Published: September 2019

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.
Phylogenetic Position and Generic Placement of The Socorro Wren (Thryomanes Sissonii)
Authors: Gómez Juan E. Martínez , Barber Brian R. , Peterson A. Townsend
Published: September 2019

Since early in its taxonomic history, placement of the Socorro Wren (Thryomanes sissonii) has been an object of contention. Of particular interest is its current placement in the genus Thryomanes, which makes that genus ditypic and leads to an odd biogeographic scenario for the Socorro Wren's colonization of Socorro Island. We assessed its phylogenetic position by analyzing 516 base pairs of mitochondrial DNA sequences from the ND2 gene of this species and 14 additional wren taxa. Contrary to its present placement, the Socorro Wren is nested phylogenetically within the House Wren species complex, being placed as sister to the clade Troglodytes aedon + T. musculus. The current hypothesis (i.e. sister to Thryomanes bewickii) is strongly invalidated by our analysis. Our analyses indicate that the most appropriate taxonomic classification for the Socorro Wren is Troglodytes sissonii.

Posición Filogenética y Ubicación Genérica de Thryomanes sissonii
Sexual Preferences of Female Brown-Headed Cowbirds (Molothrus Ater) for Perched Song Repertoires
Authors: Hosoi S. Aki , Rothstein Stephen I. , O'Loghlen Adrian L.
Published: September 2019

The importance of repertoire size to mate choice by female songbirds has been widely debated but has not been addressed in Brown-headed Cowbirds (Molothrus ater; hereafter ”cowbirds”), despite extensive work on this species' songs. Male cowbirds cycle through repertoires of 2–8 perched song (PS) types in rapid sequences immediately prior to and during copulation, which suggests that repertoire size or content is important in mating contexts. Because male mating success in one well-studied cowbird population is correlated with large PS repertoires, we predicted that repertoire size is a cue in female mate choice. To test that prediction, we played three repetitions of conspecific songs in rapid succession to estradiol-primed female cowbirds (M. a. obscurus), to simulate the rapid song sequences that accompany naturally occurring matings. Females were presented with three different PS types, three repetitions of the same type, and heterospecific control songs of the same duration as the conspecific playbacks. Females gave longer copulation solicitation displays to three different PS types than to three repetitions of a single PS type, regardless of whether the playback songs were local or foreign. This is one of the few experimental studies on songbirds to show greater female responsiveness to a song repertoire presented so as to mimic singing in a natural mating context, and the first to present such a result for cowbirds. We conclude that presentation of multiple PS types is more sexually stimulating to females than a single type, because females prefer larger repertoires or singing patterns with a higher frequency of song-type switching.

Preferencias Sexuales de Hembras de Molothrus ater por Repertorios de Canto de Percha
Concordance Between Morphological and Molecular Markers in Assessing Hybridization Between Sharp-Tailed Sparrows in New England
Authors: Shriver W. Gregory , Gibbs James P. , Vickery Peter D. , Gibbs H. Lisle , Hodgman Thomas P. , Jones Peter T. , Jacques Christopher N.
Published: September 2019

Hybridization is pivotal in framing ideas about species concepts and has the potential to produce novel genotypes that may serve as starting points for new evolutionary trajectories. Presently, Nelson’s Sharp-tailed Sparrows (Ammodramus nelsoni subvirgatus) and Saltmarsh Sharp-tailed Sparrows (A. caudacutus caudacutus) are in contact in salt marshes of Maine, New Hampshire, and northern Massachusetts. These two species hybridize, but the extent and direction of introgression has not been determined. We assessed morphological and genetic variation of 123 sharp-tailed sparrows from 5 salt marshes in New England. We used six morphological variables, including a plumage-scoring index, and five mic-rosatellite primers to assess the extent of introgression and to determine whether there was concordance between phenotypic and genotypic variation. We identified apparent hybrids and each of the two sharp-tailed sparrow species using a plumagescoring index. In general, we found that hybrids were more similar morphologically and genetically to Saltmarsh Sharp-tailed Sparrows. The alleles of hybrids were 62% Saltmarsh and 38% Nelson’s Sharp-tailed Sparrows, supporting the asymmetrical hybridization hypothesis.

Concordancia entre Marcadores Morfológicos y Moleculares al Evaluar la Hibridación entre Ammodramus nelsoni subvirgatus y A. caudacutus caudacutus en Nueva Inglaterra
Scytalopus Stilesi, A New Species of Tapaculo (Rhinocryptidae) From the Cordillera Central of Colombia
Authors: Cuervo Andrés M. , Cadena Carlos Daniel , Krabbe Niels , Renjifo Luis Miguel
Published: September 2019

We describe Scytalopus stilesi, an overlooked species of tapaculo endemic to Colombia, on the basis of a series of eight specimens taken in 2002 and comparative analyses of its vocalizations, mitochondrial DNA sequences, and distribution. The new species ranges in the northern half of the Cordillera Central of the Colombian Andes in the Departments of Antioquia, Caldas, and Risaralda, in cloud forests between 1,420 and 2,130 m above sea level. The song, calls, and female song of the new species differ distinctly from those of all other known Scytalopus taxa. Phylogenetic analyses based on sequences of the cytochrome-b gene strongly suggest affinities with S. robbinsi of southwestern Ecuador and with two as-yet-undescribed tapaculos from the Colombian Andes. Scytalopus stilesi coexists locally with, though it is ecologically segregated from, S. atratus, S. latrans, and S. spillmanni. The mid-elevation premontane wet forests to which the new species is restricted have been subject to severe deforestation and fragmentation. The species is, however, relatively common in continuous mature-forest remnants, large primary-forest fragments, riparian forests, and tall secondary-forest patches. We employed a geographic information system (GIS) approach to model the potential distribution of the new species and assess its conservation status under the International Union for the Conservation of Nature (IUCN) criteria. Scytalopus stilesi does not qualify as threatened according to those criteria, but it should be regarded as near threatened. The new species coexists with numerous threatened bird species that are in need of more effective conservation.
Cerulean Warbler (Dendroica Cerulea) Microhabitat and Landscape-Level Habitat Characteristics in Southern West Virginia
Authors: Weakland Cathy A. , Wood Petra Bohall
Published: September 2019

The Cerulean Warbler (Dendroica cerulea) is a species of conservation concern in eastern North America, where declines in its population have been documented over the past several decades. A high proportion of the population occurs in forested areas of southern West Virginia, where it may be threatened by loss and degradation of forested habitat from mountaintop mining and valley fill (MTMVF). We examined, from a landscape perspective, the effects of forest fragmentation (in particular, effects of fragment size and response to edges) on Cerulean Warblers, using territory mapping techniques and geographic information system (GIS) technology in portions of four counties in southwestern West Virginia. We quantified landscape characteristics from digitized aerial photographs and measured microhabitat characteristics on spot-mapping plots. Territory density of Cerulean Warblers was 4.6 territories per 10 ha in intact forest and 0.7 territories per 10 ha in fragmented forest. The best habitat model included both landscape and microhabitat variables and indicated that territory density increased with increasing snag density, percentage of canopy cover >6–12 m and >24 m in height, and distance from mine edge. Models for predicting microhabitat use at the territory level were weak, indicating that microhabitat characteristics of territories were similar to habitat available on spot-mapping plots. The species did not appear to avoid internal edges, such as natural canopy gaps and open-canopy or partially open-canopy roads. Territory placement on ridges was greater than expected, and in bottomlands (ravines) and midslopes less than expected, given availability. Fifty percent of all territories were on ridges. Preference for ridges suggests that MTMVF may have a greater effect on Cerulean Warbler populations than other sources of forest fragmentation, given that ridges are removed in MTMVF. Our data indicate that Cerulean Warblers are negatively affected by mountaintop mining from loss of forested habitat, particularly ridgetops, and from degradation of remaining forests, as evidenced by lower territory density in fragmented forests and lower territory density closer to mine edges.
Laying Plasticity in an Avian Brood Parasite
Authors: Forman Dan W.
Published: September 2019

Females of some bird species “steal“ the parental care of other breeding individuals by laying eggs parasitically in their nests. In most populations, conspecific brood parasites lay parasitically before laying in their own nests. By contrast, in a young and expanding Common Moorhen (Gallinula chloropus) population, 17.4% (n = 8) of brood parasites laid parasitically when their own clutches were currently being incubated, and 13.1% (n = 6) laid parasitically when they were tending to their young. This result differs from previous data on conspecific brood parasitism in this (and other) avian species and suggests that sitespecific ecological conditions exert differing selective influences on the behavioral development of populations. The behavior adopted by individual vertebrate species may not, therefore, be rigidly fixed throughout their geographic range.
Effects of Weather and Population Density on Reproductive Success and Population Dynamics in a Song Sparrow (Melospiza Melodia) Population: A Long-Term Study
Authors: Chase Mary K. , Nur Nadav , Geupel Geoffrey R.
Published: September 2019

We studied the relationships among weather, reproductive success, and population density over 21 years (1980-2000) in a resident Song Sparrow (Melospiza melodia) population in coastal scrub habitat. Our goals were to test potential relationships between annual variation in weather and reproductive success, to evaluate whether reproductive success is density dependent, and to explore the effects of weather and population density on population dynamics. We analyzed the following components of reproductive success: clutch size, hatching success, fledging success, number of young fledged per successful nest, nestling weight, number of fledglings produced per female, number of broods per female, and probability of nest survival. During the study period, several very wet El Niño-Southern Oscillation (ENSO) events as well as an eight-year period of below-average rainfall occurred. Annual reproductive success and population density showed strong positive relationships to annual rainfall levels. Song Sparrow reproductive success increased with increasing rainfall and peaked at above-average rainfall levels. However, no component of reproductive success was related to an index of variation in the ENSO (i.e. Southern Oscillation Index). The components of reproductive success most strongly associated with rainfall were probability of nest survival and length of the breeding season. Nest predation rates were lower in wetter years. Song Sparrows nested over a longer period in years with higher rainfall and lower summer temperatures, and there was an increase in the number of successful broods per female in wetter, cooler years. Nestling weight was not associated with annual rainfall. Neither clutch size nor the onset of laying was associated with spring temperatures. Warmer summer temperatures were associated with a decrease in number of young fledged per successful nest. We found no evidence for decreased reproductive success in years of higher population density, which suggests that reproductive success was limited primarily by density-independent factors, such as weather. Changes in population density from one year to the next were positively related to rainfall-associated variation in reproductive success and negatively related to population density in the previous year. Rainfall in the previous year explained at least 49% of the annual variation in population density. Thus, population dynamics appeared to be driven both by density-independent and density-dependent factors.
Homing Success of Migrant Versus Nonmigrant Dark-Eyed Juncos (Junco Hyemalis)
Authors: Keiser Jeffrey T. , Ziegenfus Charles W. S. , Cristol Daniel A.
Published: September 2019

Within a population, the evolution of migratory behavior is accompanied by a suite of physiological, behavioral, and cognitive adaptations. Spatial memory is associated with the hippocampus in mammals and birds; in some cases, hippocampal neuroanatomy correlates with differences in behavior. In a recent study, a migratory subspecies of sparrow, the Dark-eyed Junco (Junco hyemalis hyemalis), performed better on room-scale spatial memory tests than did a nonmigratory conspecific. Migrants collected after migration also possessed greater hippocampal neuron density, which suggests a neurological basis for differences in spatial memory and a link between migratory behavior and enhanced spatial memory. It is likely that homing behavior, like migration, relies to some extent on spatial memory. In some instances, spatial memory performance has generalized across spatial scales, with pronounced differences at larger scales. We tested whether differences in spatial memory between migrants and nonmigrants, previously observed at a room scale, were detectable at a landscape scale; specifically, we investigated whether differences in homing ability could be detected after displacements of 1–40 km. We found no difference in number of returning individuals or in duration of return. Our results suggest that homing in this species may not rely on aspects of spatial memory that differed in aviary tests.
Edge Avoidance by Nesting Grassland Birds: A Futile Strategy in a Fragmented Landscape
Authors: Renfrew Rosalind B. , Ribic Christine A. , Nack Jamie L.
Published: September 2019

Some grassland passerine species are considered area-sensitive, but the mechanisms underlying that phenomenon are not understood, particularly on grazed grasslands. Area sensitivity may result from edge avoidance or higher nest predation near edges, both of which may be influenced by predator activity or cattle-induced vegetational differences between pasture edge and interior. We assessed the effect of distance to edge on nest density and predation Savannah Sparrows (Passerculus sandwichensis), Grasshopper Sparrows (Ammodramus savannarum), Bobolinks (Dolichonyx oryzivorus), and meadowlarks (Sturnella spp.) along wooded and nonwooded edges of Wisconsin pastures in 1998-2000 and the activity of potential mammalian nest predators along those edges in 2000-2001. We found a positive relationship between nest density and distance from edge for all edge types combined, but that was not the result of effects of wooded edges: we found no difference in density between nests located <50 or <100 m from wooded versus nonwooded (crop or grassland) edges. Models that included combinations of vegetation structure (e.g. concealment), initiation date, year, or edge variables (or all four) were poor predictors of the probability of nest predation. Placing nests away from edges, therefore, did not reduce the risk of nest predation. Eight species known to prey on grassland bird nests were documented along pasture edges, raccoon (Procyon lotor) being the most common. Frequency of raccoon and thirteen-lined ground squirrel (Spermophilus tridecemlineatus) visitation was higher along wooded edges and nonwooded edges, respectively. Cattle (Bos taurus) activity did not differentially affect vegetation height-density along edges compared with that in the pasture interior. Possible reasons for predation risk being similar in both pasture interiors and edges in a fragmented landscape include the ease with which predators can move within pastures, high percentage of resident grassland predators, and small size (median = 47.2 ha) of pastures.