David N Bonter

Cornell University | CU · Laboratory of Ornithology

Numerous studies have shown the positive association between nature engagement and well‐being. During the early phases of the SARS‐CoV‐2 pandemic, nature engagement changed dramatically as mental health and well‐being declined across the globe. This study examines how psychological connection to nature and engagement with nature in various forms is...

To what degree is niche partitioning driven by underlying patterns in resources such as food, rather than by competition itself? Do discrete niches exist? We address these questions in the context of Cooper's and sharp‐shinned hawks, two broadly sympatric, North American, bird‐eating raptors in the genus Accipiter. We find that the resource base, a...

The presence of superabundant prey resources can influence the abundance and distribution of raptors. To investigate how an unintentionally provided prey superabundance may affect the regional distribution of raptors, we extracted data on Red-tailed Hawk (Buteo jamaicensis) and Turkey Vulture (Cathartes aura) observations from eBird (ebird.org) for...

The Harris's Hawk (Parabuteo unicinctus), a social raptor species, often breeds and hunts cooperatively in groups typically consisting of a dominant breeding pair and one or more auxiliary group members. Why these birds form social groups is not completely understood, but one hypothesis is that the ability to hunt cooperatively may benefit groups w...

Saltmarsh sparrows (Ammospiza caudacuta) and seaside sparrows (A. maritima) are species of conservation concern primarily due to global sea-level rise and habitat degradation. Environmental mercury (Hg) contamination may present additional threats to their reproductive success and survival. To assess site-specific total mercury (THg) exposure and i...

Radio-frequency identification (RFID) technology has gained popularity in ornithological studies as a way to collect large quantities of data to answer specific biological questions, but few published studies report methodologies used for validating the accuracy of RFID data. Further, connections between the RFID data and the behaviors of interest...

Wild bird feeding is a popular and growing activity, with approximately half of households participating in nations including the United States, Canada, the United Kingdom, New Zealand, and Australia. Supplemental feeding can increase survival and reproductive success of birds (which is often a goal of supplemental feeding efforts), but it raises c...

en Globally, billions of U.S. dollars are spent annually to provide food for wild birds. The variety of foods offered continues to diversify, yet the consequences for wildlife of this widespread human activity are relatively unexplored, as are the relative benefits of different types of supplemental food. To investigate the potential implications o...

Across the globe, millions of people feed wild birds and this practice has profound implications for many bird species. To better understand the effects of this supplemental feeding, many researchers have compared birds with access to inexhaustible supplemental food to those without access. However, the consistency of supplemental food availability...

Saltmarsh sparrows ( Ammospiza caudacuta ) and seaside sparrows ( A. maritima ) are species of conservation concern primarily due to global sea-level rise and habitat degradation. Environmental mercury (Hg) contamination may present additional threats to their reproductive success and survival. To assess site-specific total mercury (THg) exposure a...

In North America, nest site competition from invasive cavity-nesting birds can limit the opportunities for successful nesting by native birds. Managing invasive species is costly and complex, requiring input from biologists, decision makers, and the public. An informed and engaged public can play an important role in mitigating the negative effects...

House Sparrow (Passer domesticus) populations declined across much of their global range in the late 20th century. Most research examining this decline is conducted in the species' native European range, but Europe encompasses a small portion of the species' current distribution. House Sparrow population trends in the United States and Canada, and...

Invasive species are a threat to global biodiversity, yet the impacts of invasive birds on the native birds with which they compete are understudied. Humans have a long history of providing and managing nest boxes to support native birds; however, their management of non-native birds has received limited research attention. We surveyed people who m...

The House Sparrow (Passer domesticus), native to Europe and Asia, has been introduced globally and is now one of the most ubiquitous birds in the world. In North America, these invasive passerines compete with native species for nest cavities, which are often limited. Because of the difficulties of extirpating an invasive species and the growing de...

Soon after its introduction to North America in 1999, West Nile virus spread rapidly across the continent and negatively impacted the populations of a diversity of avian host species. The potentially continuing effects of the introduction of the virus, however, have not been fully explored. To determine whether long-term population trends are corre...

Backyard bird feeding is one of the most common ways people engage with wildlife in many parts of the world. Given its scale, it can have profound consequences for the ecology of feeder birds and their behaviour. While previous work has primarily explored socio‐demographic factors associated with bird feeding, how observations of nature at backyard...

Urbanization causes the simplification of natural habitats, resulting in animal communities dominated by exotic species with few top predators. In recent years, however, many predators such as hawks, and in the US coyotes and cougars, have become increasingly common in urban environments. Hawks in the Accipiter genus, especially, are recovering fro...

Although the effects of bird feeding on avian species have been extensively examined, few studies evaluate the indirect effects of bird feeding on non-target taxa. Bird seed could provide direct nourishment to several mammalian species (e.g., Lagomorpha, Rodentia, and Cetartiodactyla), potentially altering their distribution and behavior with possi...

Yellow Warblers (Setophaga petechia) are abundant breeding birds in North America, but their migratory and non-breeding biology remain poorly understood. Studies where genetic and isotopic techniques were used identified parallel migration systems and longitudinal segregation among eastern- and western-breeding populations of Yellow Warblers in Nor...

Humans have long provided nest boxes in a widespread and popular effort to augment nesting sites for cavity-nesting birds. Nest boxes, however, may provide easy access for predators and thereby create ecological traps for nesting birds. Predator exclusion techniques are often deployed at nest boxes to reduce nest predation, but few studies have tes...

Members of different species often engage in aggressive contests over resources. This series of aggressive contests between species may result in an interspecific dominance hierarchy. Such hierarchies are of interest because they could be used to address a variety of research questions, for example, do similarly ranked species tend to avoid each ot...

Anthropogenic changes to the landscape and climate cause novel ecological and evolutionary pressures, leading to potentially dramatic changes in the distribution of biodiversity. Warm winter temperatures can shift species’ distributions to regions thatwere previously uninhabitable. Further, urbanization and supplementary feeding may facilitate rang...

The study of aggressive interactions between species has, to date, usually been restricted to interactions among small numbers of ecologically close competitors. Nothing is known about interspecific dominance hierarchies that include numerous, ecologically varied species. Such hierarchies are of interest because they could be used to address a vari...

Successful reproduction often depends upon parents providing offspring with resources and protection. In birds, reproductive success can often be enhanced by parents engaging in antipredator behaviors, but these behaviors can be costly. Theoretically, individuals should temporally modify the intensity of nest defense behavior to balance the costs a...

A number of colonial waterbird species have been documented nesting on roof-tops throughout Europe and North America. The most common hypothesis explaining why gulls (Laridae) select roof-tops for nesting has been that population growth rates are higher than territory vacancy rates in traditional (island) habitat, suggesting that roof-tops are a no...

Skewed adult sex ratios sometimes occur in populations of free-living animals yet the proximate mechanisms, timing of sex-biases, and the selective agents contributing to skew remain a source of debate with contradictory evidence from different systems. We investigated potential mechanisms contributing to sex biases in a population of herring gulls...

Recent studies have demonstrated the presence of risk-based variation in alarm calling in many vertebrate species. Most of the studies on birds, however, have focused on passerine systems perhaps due to the traditional view that passerine vocalizations are more complex. We investigated the presence of a risk-based alarm calling system in a nonpasse...

Modern climate change has resulted in an advancement of spring phenology throughout the Northern Hemisphere, and studies suggest that many birds are arriving earlier to their breeding grounds in response to these changing spring conditions. Past studies on spring arrival of migrating birds often rely on long-term records from a single banding stati...

Extreme storm events encountered during any stage of the annual cycle can result in increased mortality and influence population dynamics. Storms during the reproductive season, when birds are tied to fixed nesting locations, can be particularly problematic. Given predicted changes in the frequency and intensity of storms in a changing climate, stu...

The threat sensitivity hypothesis predicts that organisms will evaluate the relative danger of and respond differentially to varying degrees of predation threat. Doing so allows potential prey to balance the costs and benefits of anti-predator behaviors. Threat sensitivity has undergone limited testing in the auditory modality, and the relative thr...

The emerald ash borer (EAB) Agrilus planipennis, first detected in 2002 in the vicinity of Detroit, Michigan, USA, is one of the most recent in a long list of introduced insect pests that have caused serious damage to North American forest trees, in this case ash trees in the genus Fraxinus. We used data from Project FeederWatch, a citizen science...

Various invasive ant species have negatively affected reproductive success in birds by disrupting nest site selection, incubation patterns, food supply, and by direct predation on nestlings. Impacts can be particularly severe when non-native ants colonize seabird nesting islands where thousands of birds may nest in high densities on the ground or i...

Daily patterns in the foraging behaviour of birds are assumed to balance the counteracting risks of predation and starvation. Predation risks are a function of the influence of weight on flight performance and foraging behaviours that may expose individuals to predators. Although recent research sheds light on daily patterns in weight gain, little...

To become more widely accepted as a valuable research tool, citizen-science projects must find ways to ensure that data gathered by large numbers of people with varying levels of expertise are of consistently high quality. Here, we describe a data validation protocol developed for Project FeederWatch, a continent-wide bird monitoring program, that...

Approaches to citizen science – an indispensable means of combining ecological research with environmental education and natural history observation – range from community-based monitoring to the use of the internet to “crowd-source” various scientific tasks, from data collection to discovery. With new tools and mechanisms for engaging learners, ci...

The causes and consequences of coloniality in seabirds, and larids in particular, have received extensive study. Here, we use the Herring Gull (Larus argentatus) as a model organism to investigate the effect of nest density on chicks' growth rate and survival. On Appledore Island, Maine, Herring Gulls nest both in dense subcolonies and in more isol...

1. Ecologists have long been interested in the role of climate in shaping species’ ranges, and in recent years, this relationship has taken on greater significance because of the need for accurate predictions of the effects of climate change on wildlife populations. Bioclimatic relationships, however, are potentially complicated by various environm...

Radio frequency identification (RFID) technology allows the unique identification of individuals and automated recording of the presence of tagged birds at fixed locations. Investigators have used RFID technology to examine questions related to pair formation, feeding rates, incubation behavior, prospecting behavior by nonbreeding birds, temporal c...

Radio frequency identification (RFID) technology can be used to implement automated bird-monitoring systems and, therefore, could be of use to field ornithologists. However, the cost of a large-scale RFID network can be prohibitive for those with limited research budgets. We describe a simple RFID reader/data logger that can be constructed for less...

Citizen science, the involvement of volunteers in research, has increased the scale of ecological field studies with continent-wide, centralized monitoring efforts and, more rarely, tapping of volunteers to conduct large, coordinated, field experiments. The unique benefit for the field of ecology lies in understanding processes occurring at broad g...

We examined a 35-year transition in the breeding bird community at a successional study site in a reforesting landscape in southwestern New York, USA. Changes in the successional plot were compared with those in two additional census plots, one in undisturbed forest and the other in a managed tree farm. The territories of 7,429 singing male songbir...

Studying the relationships among introduced species, their preferred habitats, and native species can be important for predicting the effects of invasions on native populations. Examining the colonization of North America by the Eurasian collared-dove Streptopelia decaocto, we quantified the habitat characteristics of sites most likely to be occupi...

A preliminary stage in developing comprehensive conservation plans involves identifying areas used by the organisms of interest. The areas used by migratory land birds during temporal breaks in migration (stopover periods) have received relatively little research and conservation attention. Methodologies for identifying stopover sites across large...

Mist nets deployed in a standard ground-level fashion capture birds approximately 0.5-2.6 m above the ground. In habitats where the vegetation extends above this height, standard mist net deployment may inadequately sample the targeted avian community and age- and sex-classes within species. Such sampling biases may raise questions regarding studie...

Background/Question/Methods Continental-scale citizen science programs rely upon dispersed networks of volunteers to gather information. Interactions between citizen scientists and principal investigators may be limited due to the large spatial scale and the number of participants involved. As such, overseeing data collection and ensuring the int...

To facilitate study of the breeding biology of parids, Grubb and Bronson (1995; Condor 97: 1067-1070) designed artificial "snags" made from polyvinyl chloride (PVC) tubes. Because the cost of artificial snags is greater than that of traditional wooden boxes, we examined alternatives to PVC snags for attracting chickadees to artificial nesting sites...

Once one of the most common species seen at bird feeding stations across much of North America in winter, the Evening Grosbeak (� occothraustes vespertinus), appears to be experiencing a population decline. Like other finches associ - ated with the boreal forest or high elevations, Evening Grosbeaks form flocks in winter, often irrupting out of the...

Effective continent-wide monitoring of bird populations requires engagement of the public in order to gather data across large spatial and temporal scales. One long-term, continental-scale monitoring program, Project FeederWatch, has enlisted more than 40 000 people from all U.S. states and Canadian provinces since 1987. The project, operated by th...

In the fall of 2005, the Directors of the U.S. Geological Survey (USGS) and the U.S. Fish and Wildlife Service (FWS) determined that to ensure that the Bird Banding Laboratory (BBL) of the USGS maintains and continues its important support of conservation and management of birds, it should be guided by a clear vision for the future. In order to car...

Assigning conservation priorities to areas used by birds during migration requires information on the relative quality of areas and habitats. The rate at which migratory birds replenish energy reserves during stopover may be used as an indicator of stopover-site quality. We estimated the rate of mass gain of 34 landbird species during stopover at a...

Assigning conservation priorities to areas used by birds during migration requires information on the relative quality of areas and habitats. The rate at which migratory birds replenish energy reserves during stopover may be used as an indicator of stopover-site quality. We estimated the rate of mass gain of 34 landbird species during stopover at a...

Feathers are increasingly collected as a nondestructive source of DNA for avian genetic research. Although feather samples are not optimal in some important ways than more robust blood or tissue samples, feather sampling requires less training for field workers, results in shorter handling times for the organism, generates no hazardous wastes, and...

Partners in Flight (PIF) is a consortium of professional and volunteer scientists and educators that promotes the conservation of landbird species. Central to the PIF conservation effort is the development of Bird Conservation Plans specific to each physiographic region of the United States. Without a coordinated priori- tization of research needs,...