Kathleen Anderson at her beloved Wolf Trap Hill Farm, May 11, 2019 (photograph by Shawn P. Carey).

Kathleen Anderson at her beloved Wolf Trap Hill Farm, May 11, 2019 (photograph by Shawn P. Carey).

Kathleen Anderson at her beloved Wolf Trap Hill Farm, May 11, 2019 (photograph by Shawn P. Carey).

Hermit Warblers (Setophaga occidentalis) sing a formulaic, type I song to attract mates, in contrast to a repertoire of more complex, type II songs to defend territories. A single, dominant type I song, or a low diversity of type I songs, often occur within a geographic area. We provide the first comprehensive description of Hermit Warbler type I song variants throughout California, USA. We recorded

The Grallaria rufula complex is currently considered to consist of 2 species, G. rufula (Rufous Antpitta) and G. blakei (Chestnut Antpitta). However, it has been suggested that the complex, populations of which occur in humid montane forests from Venezuela to Bolivia, comprises a suite of vocally distinct yet morphologically cryptic species. We sequenced nuclear and mitochondrial DNA for 80 individuals

The biodiversity of the Neotropics is considerable, but it is likely underestimated owing to gaps in sampling effort and a focus on using morphological features of animals to determine species differences rather than divergence in their mating signals and behavior. Recent multi-trait analyses incorporating morphological, plumage, and vocal data have allowed for more accurate quantification of tropical

Declines in reproductive performance among older age classes have been reported in many bird and mammal species, and are commonly presented as demonstrating reproductive senescence. However, no declines in performance could be demonstrated in studies of several bird species. We measured reproductive performance in Common Terns (Sterna hirundo) of known age (2–28 yr) during a 19-yr period at a site

Individual recognition is a social behavior that occurs in many bird species. A bird’s ability to discriminate among familiar and unfamiliar conspecifics is critical to avoid wasting resources such as time and energy during social interactions. Black-capped Chickadees (Poecile atricapillus) are able to discriminate individual female and male chick-a-dee calls, potentially male and female tseet calls

Kathleen Anderson at her beloved Wolf Trap Hill Farm, May 11, 2019 (photograph by Shawn P. Carey).

Tony Bledsoe at the Pymatuning Laboratory of Ecology (courtesy of Meg Bledsoe).

We studied the phylogeny, biogeography, and diversification of suboscine passerines in the genus Scytalopus (Rhinocryptidae), a widespread, species-rich, and taxonomically challenging group of Neotropical birds. We analyzed nuclear (exons, regions flanking ultraconserved elements) and mitochondrial (ND2) DNA sequence data for a taxonomically and geographically comprehensive sample of specimens collected

Migratory birds are demonstrating changes in phenology linked to climate change. Understanding these changes requires connecting events that occur over the multiple regions occupied during their annual cycle. The Burrowing Owl (Athene cunicularia) is a species of concern in North America, with pronounced declines in regions of the Great Plains. Using a dataset that spanned 10 breeding sites from South

In 1920, the 37th volume of The Auk included 41 major articles. The lead was a memorial for William Brewster (1851–1919). It was followed by tributes to Brewster and Lyman Belding (1829–1917), and announcements of adoptions of memorials for Brewster. In the inaugural issue of the year, editor Witmer Stone placed a notice of a publication delay and a backlog of submissions, requested a Publication Fund

Natal dispersal and local recruitment are affected by factors both intrinsic and extrinsic to juveniles and may affect fitness. Understanding the relationship between dispersal and population density in birds has been hindered by a lack of long-term studies and a focus on resident species has neglected the role of weather operating at large spatial scales. I studied local recruitment and the reproductive

Density dependence is a conceptual cornerstone of avian population biology and, in territorial songbirds, past research has emphasized interactions among food limitation, density, and reproduction. Documenting the importance of density effects is central to understanding how selective forces shape life histories and population dynamics. During the 2008–2011 breeding seasons, we nearly doubled overall

Tropical mountains feature marked species turnover along elevational gradients and across complex topography, resulting in great concentrations of avian biodiversity. In these landscapes, particularly among morphologically conserved and difficult to observe avian groups, species limits still require clarification. One such lineage is Scytalopus tapaculos, which are among the morphologically most conserved

Grooming by birds is thought to serve essential anti-parasite functions. While preening has been well studied, little is known about the function of scratching in birds. We conducted a series of experiments to determine the effectiveness of scratching for controlling feather lice (Columbicola columbae) on Rock Pigeons (Columba livia). First, we used a hobbling technique to impair scratching. After

Ornithology, fourth edition, by GillFrank B., PrumRichard O., and contributions by RobinsonScott K.. 2019. W. H. Freeman & Co., Macmillan Learning. New York. xxii + 666 pp., 400+ color photos, illustrations, maps, and tables. $145.99 (hardcover; e-version available). ISBN 978-1464184369.

Bird Species: How They Arise, Modify and Vanish by TietzeDieter Thomas, Editor. 2018. Fascinating Life Sciences Series. SpringerOpen. xii + 266 pp., 44 figures. Gewerbestrasse, Switzerland. $57.49 (hardback), $0.00 (eBook), ISBN 978-3-319-91688-0.

Optimizing breeding phenology, an important aspect of fitness, is complex for migratory species as they must make key timing decisions early, and remotely, from breeding sites. We examined the role of weather (locally and cross-seasonally), cavity availability, and competitive exclusion in determining among-year variation in breeding phenology over 17 yr for 2 migratory, cavity-nesting birds: Mountain

The availability of detailed information that encompasses the geographic range of a species, spans a long-term temporal range, and yields individual information (e.g., age and sex), is a principle challenge in ecology. To this end, the North American Bird Banding Laboratory maintains a unique and underutilized dataset that can be used to address core questions of phenological change in migratory birds

Mixed-species flocks are ubiquitous in forest bird communities, yet the extent to which positive (facilitative) or negative (competitive) interactions structure these assemblages has been a subject of debate. Here, we describe the fine-scale foraging ecology and use network analysis to quantify mixed-species flocking interactions of an insectivorous bird community in hardwood forests of north-central

In all animals, susceptibility to parasites can differ among individuals. Young, nest-bound birds are exposed to a diversity of nest-dwelling ectoparasites that typically feed on their blood. Within broods, hatching asynchrony creates size hierarchies that result in morphological and physiological variation among nest mates, and susceptibility to parasites also may vary predictably with this size hierarchy

The Wonderful Mr Willughby: The First True Ornithologist by BirkheadTim. 2018. Bloomsbury Publishing, London, UK. xii + 353 pp., 50 color images, 32 black-and-white illustrations, 3 tables, 3 charts, 5 maps, and 4 appendices. (hardcover). ISBN-10 1408878488.

Tsukasa Nakamura talking with John C. Wingfield at the annual meeting of the Ornithological Society of Japan in September 1995 (photograph by Haruo Kuroda).

Androgenic activation of intracellular androgen receptors (AR) influences avian vocal production, though this has largely been investigated at the level of the brain. We investigated the influence of predominantly peripheral AR on vocal output in wild Golden-collared Manakins (Manacus vitellinus). In this suboscine species, males court females by performing acrobatic displays and by producing relatively

Bile salts are the major end-metabolites of cholesterol and are important in lipid digestion and shaping of the gut microflora. There have been limited studies of bile-salt variation in birds. The purpose of our study was to determine bile-salt variation among birds and relate this variation to current avian phylogenies and hypotheses on the evolution of bile salt pathways. We determined the biliary

Vocal behavior in tropical hummingbirds is a new area of study. Here, we present findings on the vocalizations and associated behaviors of two species: Sombre Hummingbird (Aphantochroa cirrhochloris) and Rufous-breasted Hermit (Glaucis hirsutus). These are the only hummingbirds in which the brain areas activated by singing have been demonstrated. They are also among the basal species of their respective

Despite their large vocal repertoires and otherwise highly versatile singing style, male mockingbirds sometimes sing in a highly repetitive fashion. We conducted a playback experiment to determine the possible signal value of different syllable presentation patterns during simulated male intrusions in the Tropical Mockingbird (Mimus gilvus) testing the hypothesis that more repetitive singing represents