When suitable nesting habitat is rare, birds may have to share it with heterospecific individuals with similar nesting requirements. The resulting species mosaic may in turn affect how breeding birds communicate vocally with each other. For instance, they may modify their vocalizations if the ambient noise produced by heterospecifics interferes with their own vocalizations. The...
The Mallard (Anas platyrhynchos) duck is a ubiquitous and socio-economically important game bird in North America. Despite their generally abundant midcontinent population, Mallards in eastern North America are declining, which may be partially explained by extensive hybridization with human-released domestically derived game-farm Mallards. We investigated the genetic composition...
Among tropical organisms, heightened habitat specialization, limited natal dispersal, and strong philopatry suggest that many species may experience reduced rates of gene flow. Diverse forms of barriers, including geographic, ecological, and behavioral barriers, further promote genetic divergence among tropical bird populations. Here, we extend our comprehension of gene flow in...
Interannual consistency (an indicator of the strength of adjustments) in migration phenology of Golden Eagles (Aquila chrysaetos) in North America is most strongly associated with the breeding region, the season, and with late-season temperature on breeding and wintering grounds. Consistency was greatest in boreal spring migration and the breeding regions of eastern Canada. Using...
During migration, birds must stopover at refueling sites to replenish energy stores, with the rate of refueling linked to stopover length, migration speed, and the timing of critical life stages, such as breeding. Under optimal migration theory, birds are expected to maximize fuel intake and minimize stopover length (the time minimization hypothesis). Within a multi-species...
Savannah Sparrows (Passerculus sandwichensis) and Tree Swallows (Tachycineta bicolor) breed and forage in the same habitat on Kent Island, a boreal island in the Bay of Fundy, New Brunswick, but respond differently to the same weather conditions. The 2 passerines are similar in body size but because Tree Swallows depend upon small flying insects captured on the wing, they may be...
Ecological and life-history variation and both interspecific and intraspecific brood parasitism contribute to diversity in egg phenotype within the same species. In this study, Barn Swallows (Hirundo rustica erythrogaster) laid eggs with high intraclutch repeatability in egg size, shape, and maculation. Despite this high intraclutch repeatability, last-laid eggs had consistently...
Nearly 70 years ago, Preston published a pioneering study in which he provided formulae for the shapes of birds’ eggs. One of these formulae is universal in that it provides an almost perfect representation for all eggs, even pyriform ones, and is better than all other formulae published since. This essentially perfect representation of egg shape is obtained by estimating the...
Mary Bomberger Brown, an ornithologist, conservation biologist, and behavioral biologist at the University of Nebraska-Lincoln (UNL), passed away in her ho
Ray Erickson, an Elective Member (1978) of the American Ornithologists’ Union (now American Ornithological Society), died August 16, 2019, in Mt. Angel, Or
Jiro Kikkawa, known best among ornithologists for his studies on the biogeography of Australian rainforest birds and the behavioral ecology of silvereyes (
The 38th stated meeting of the American Ornithologists’ Union (AOU), the first of the “Roaring Twenties,” was held in Washington, D.C. Business meetings we
The typical owl family (Strigidae) comprises 194 species in 28 genera, 14 of which are monotypic. Relationships within and among genera in the typical owls have been challenging to discern because mitochondrial data have produced equivocal results and because many monotypic genera have been omitted from previous molecular analyses. Here, we collected and analyzed DNA sequences of...
Endotherms dissipate heat to the environment to maintain a stable body temperature at high ambient temperatures, which requires them to maintain a balance between heat dissipation and water conservation. Birds are relatively small, contain a large amount of metabolically expensive tissue, and are mostly diurnal, making them susceptible to physiological challenges related to water...
Despite having one of the most robust fossil records within core-gruiform birds (rails, cranes, and allies), the biogeographic history of Gruidae (cranes) and key drivers of diversification within this group remain largely unknown. The Eogruidae of Eurasia represent some of the earliest known crane-like fossils. Here, we present description of a new species represented by a well...
We examined species limits, admixture, and genetic structure among populations in the Bicknell’s Thrush (Catharus bicknelli)–Gray-cheeked Thrush (C. minimus) species complex to establish the geographic and temporal context of speciation in this group, which is a model system in ecology and a high conservation priority. We obtained mitochondrial ND2 sequences from 186 Bicknell’s...
Individuals should prefer and use habitats that confer high fitness, but habitat use is not always adaptive. Vegetation in natural landscapes changes gradually and the ability of species to adaptively adjust their habitat use to long-term changes is largely unstudied. We studied nest patch and territory use over 28 yr in Orange-crowned Warblers (Oreothlypis celata) in a system...
The phenology of migrating birds is shifting with climate change. For instance, short-distance migrants wintering in temperate regions tend to delay their migration in fall during spells of warmer temperature. However, some species do not show strong shifts, and the factors determining which species will react to temperature changes by delaying their migration are poorly known...
Many birds nest in association with aggressive birds of other species to benefit from their protection against predators. We hypothesized that the protective effect also could extend to foraging resources, whereby the resultant resource-enriched habitats near a nest of aggressive raptors could be an alternative cause of associations between nesting bird species with non...
While foraging, a predator can feed solitarily or in a group. The net energy gain of joining a group is predicted to vary with prey patch quality, species-specific prey capture behavior, and the size and species composition of the predator group. In coastal Newfoundland, Canada, capelin (Mallotus villosus), a key forage fish, migrates inshore to spawn during the summer, resulting...
Breeding output of geese, measured as the proportion of juveniles in autumn or winter flocks, is lower in years with a late onset of spring in some species, but higher in at least one other species. Here we argue that this is because the timing of spring affects different stages of the reproductive cycle differently in different species. Because the effects on 2 different stages...
Thomas W. Custer, a member of the Cooper Ornithological Society (COS) since 1965, the American Ornithologists’ Union (AOU; now American Ornithological Soci
Lovett Williams, Jr., known as a legend in the Wild Turkey (Meleagris gallopavo) world and an Elective Member of the AOU since 1973, died on April 30, 2014
About 70 reviews of recent literature were published in 1919, not including papers briefly reviewed for the sections, The Ornithological Journals and Ornit