Nathan W. Cooper

Smithsonian's National Zoo & Conservation Biology Institute

The importance of understanding the geographic distribution of the full annual cycle of migratory birds has been increasingly highlighted over the past several decades. However, the difficulty of tracking small birds between breeding and wintering areas has hindered progress in this area. To learn more about Kirtland's warbler Setophaga kirtlandii...

Many tropical habitats experience pronounced dry seasons, during which arthropod food availability declines, potentially limiting resident and migratory animal populations. In response to declines in food, individuals may attempt to alter their space use to enhance access to food resources, but may be socially constrained from doing so by con- and...

Harsh weather in spring presents energetic challenges to birds during migration and upon reaching the breeding grounds, and yet, birds often arrive well before breeding begins. We studied a population of Eastern Kingbirds in eastern Oregon from 2004 through 2007. Early arriving kingbirds faced the poorest weather conditions, and therefore we predic...

Currently, the deployment of tracking devices is one of the most frequently used approaches to study movement ecology of birds. Recent miniaturization of light‐level geolocators enabled studying small bird species whose migratory patterns were widely unknown. However, geolocators may reduce vital rates in tagged birds and may bias obtained movement...

Understanding the consequences of global change for migratory birds is complex as individuals are exposed to diverse conditions and experiences that interact across their annual cycle. Species distribution models (SDMs) can serve as a powerful tool that help us understand how species distributions respond to global change. However, SDMs applied to...

Natália Stefanini Da Silveira Rachael W. Herman The AOS Harry R. Painton Award, given in odd-numbered years, is presented to the author of an outstanding paper published in the two preceding years in Ornithological Applications. The award was established in 1961 through a bequest from physician and eminent amateur ornithologist Harry Painton; a hi...

Allison E. Huysman The Florence Merriam Bailey Award—named for the first woman “associate” of the American Ornithologists’ Union (AOU) in 1885, who was also the first woman elected as a fellow of the AOU in 1929—recognizes an outstanding article published in Ornithology (odd-numbered years) or in Ornithological Applications (even-numbered years) by...

Background Each spring and fall billions of songbirds depart on nocturnal migrations across the globe. Theory suggests that songbirds should depart on migration shortly after sunset to maximize their potential for nightly flight duration or to time departure with the emergence of celestial cues needed for orientation and navigation. Although captiv...

Background Weather can have both delayed and immediate impacts on animal populations, and species have evolved behavioral adaptions to respond to weather conditions. Weather has long been hypothesized to affect the timing and intensity of avian migration, and radar studies have demonstrated strong correlations between weather and broad-scale migrat...

For many bird species, but especially aerial insectivores, reproduction depends on weather. Climate change is likely to intensify effects, but with uncertain consequences. We report 22 years of data on Eastern Kingbird (Tyrannus tyrannus) reproduction for two populations located in different hygric environments undergoing climate change; mesic cent...

Context Brown-headed cowbirds (Molothrus ater), through brood parasitism, can exert extrinsic population growth pressures on North American songbirds. Cowbird removal programs may reduce parasitism rates on host species but can be expensive and difficult to implement throughout a host species’ breeding range. Aim We estimated cowbird abundance and...

Amelia-Juliette Demery The Florence Merriam Bailey Award, named for the first woman “associate” of the AOU (1885) and the first woman elected as a Fellow of the AOU (1929), recognizes an outstanding article published in Ornithology or in Ornithological Applications by an early-career AOS member. This year’s award is presented to Amelia-Juliette Dem...

(left) Teresa Pegan and (right) Benjamin Winger Every two years, the American Ornithological Society bestows the Brina C. Kessel Award for a paper published during the preceding two years in Ornithology (formerly The Auk: Ornithological Advances) that has made an exceptional contribution to ornithology. Given in even-numbered years and consisting o...

Knowledge of the geographic linking of individuals or populations between different annual life cycle stages is essential for effective conservation decision making. The Willet (Tringa semipalmata) is composed of two distinct subspecies that are separated by breeding habitat in North America, with eastern Willets breeding in estuarine marshes along...

By combining all available banding and tracking data, we found that Willets (Tringa semipalmata) have a strong migratory connectivity between breeding and nonbreeding locations at the range-wide and subspecies levels, exposing two subspecies to varying threats such as hunting for the eastern subspecies (T. s. semipalmata) and climatically-altered c...

Migratory animals experiencing substantial change in diet and habitat across the annual cycle may have corresponding shifts in host‐associated microbial diversity. Using automated telemetry and radio tags to recapture birds, we examined gut microbiota structure in the same population and often same individual of Kirtland's Warblers (Setophaga kirtl...

A female Kirtland’s Warbler was observed and captured on 12 February 2019 at the Font Hill Nature Reserve (18°02′ N, 77°57′ W) on the south coast of Jamaica, hundreds of kilometers southwest of the typical nonbreeding range of Kirtland’s Warblers. This is the first report of a Kirtland’s Warbler (Setophaga kirtlandii) in Jamaica. The individual was...

en The size of the pectoral muscle is an important component of body condition in birds and has been linked to indices of fitness and migratory performance. Bauchinger et al. (2011. Journal of Ornithology 152: 507–514) developed, calibrated, and validated an aluminum “muscle meter” device that estimates the size of pectoral muscles noninvasively. T...

Sexual habitat segregation during the wintering period is a widespread phenomenon and has important implications for the ecology and conservation of migratory birds. We studied Black-and-white Warblers (Mniotilta varia) wintering in second-growth scrub and old-growth mangrove forest in Jamaica to quantify sexual habitat segregation and explore whet...

Understanding how migratory animals respond to spatial and temporal variation in habitat phenology is critical for identifying selection pressures and tradeoffs at different life history stages. We examined the influence of breeding habitat phenology on life history timing of the eastern willet (Tringa semipalmata semipalmata) across a latitudinal...

Technology has revolutionized our ability to track animals across the globe, significantly advancing our understanding of animal movement [1, 2]. Technological and logistical challenges, however, have led to non-migratory movements that fall outside of the territory/home range paradigm, receiving less attention. This may have resulted in a widespre...

The relative importance of predators and resources (i.e. food) for the dynamics of migratory bird populations is poorly known. Resource availability may be more likely in resource poor environments, but given that nest failure in most systems is due mainly to predation, predator effects may predominate. We document a rapid decline of an isolated ea...

Understanding the population dynamics of migratory animals throughout the full annual cycle is critical for effective conservation, and requires knowing where populations are located throughout the year. For most Neotropical−Nearctic migratory bird species, breeding distributions are well-described, but less is generally known about their migratory...

Understanding the population dynamics of migratory animals throughout the full annual cycle is critical for effective conservation, and requires knowing where populations are located throughout the year. For most Neotropical-Nearctic migratory bird species, breeding distributions are well-described, but less is generally known about their migratory...

ABSTRACT. Understanding migratory connectivity is fundamental to the ecology, evolution, and conservation of migratory species. The endangered Kirtland’s Warbler (Setophaga kirtlandii) has a restricted breeding range in early successional jack pine (Pinus banksiana) forests with most of the population in northern Michigan and smaller subpopulations...

We documented parental behaviour and paternity of eastern kingbirds (Tyrannus tyrannus) to test the predictions that paternal care would decline with increasing loss of paternity, increasing nesting density (a proxy for probability of paternity loss), male quality, and number of fertile females available in the population. Extra-pair young were fou...

How animals use space has fundamental behavioral and ecological implications. Utilization distributions are among the most common methods for quantifying space use and have advanced our knowledge of animal ecology in a variety of ways. However, until recently, they were limited to 2 spatial dimensions (2D), despite the fact that most taxa use their...

Devising methods for sampling arthropods presents many challenges, including understanding possible differences in results obtained by different individuals (precision), investigating differences between estimates and the actual variable of interest (accuracy), and assessing the effort and cost of a given method (efficiency). We assessed the precis...

Among migratory passerines, the first birds to arrive on the breeding grounds are usually older males. Early arrival by older birds may be driven by experience, age-dependent changes in body condition, age-dependent access to resources during the nonbreeding period, or latitudinal segregation by age. Males may arrive earlier than females (protandry...

Theory predicts that maximal fitness is obtained by individuals who begin to breed immediately upon reaching sexual maturity. However, delayed breeding occurs regularly in some taxa, and in birds and mammals is most often associated with long lifespan and/or limited access to suitable habitats. Delayed breeding is not expected among relatively shor...