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Jeffrey Buler - University of Delaware. Newark, DE, US

Jeffrey Buler

Professor, Wildlife Ecology | University of Delaware


Prof. Buler's current research focuses on radar biology, avian ecology and migration, landscape ecology, and conservation biology.






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UD researcher Jeff Buler protects birds against light pollution Spotlight on bird migration




Jeff Buler is a Professor in the Department of Entomology and Wildlife Ecology at the University of Delaware. Dr. Buler established the Aeroecology Program in 2011 and has lead the development of novel methods for using weather surveillance radars to study the broad-scale distribution, movement, and habitat use patterns of flying animals, particularly migratory birds. His broad research interests include avian ecology, landscape ecology, remote-sensing, and conservation biology. In recent years, his research has focused on the impacts of artificial light at night on the flight behavior and stopover distributions of migratory land birds and modeling bird distributions and habitat relationships over broad geographic scales to assess bird response to habitat restoration/management and climate change. Dr. Buler is also a Senior Project Scientist for Agrinerds, a startup company that develops software and hardware solutions for the animal food industry. He leads the development of the Waterfowl Alert Network, a web application that warns the poultry industry when waterfowl, a major reservoir for avian influenza, are in close proximity to their farms.

Industry Expertise (2)



Areas of Expertise (8)

Bird Migration

Radar Aeroecology

Landscape Ecology

Species Distribution Modeling

Stopover Ecology

Light Pollution


Avian Influenza

Media Appearances (10)

Mapping migration

University of Delaware UDaily  online


“Songbirds are often naive about the places that they’re stopping over; they don’t necessarily know where the resources are or where the dangers are,” said Jeff Buler, professor of wildlife ecology in UD’s College of Agriculture and Natural Resources. “When they’re in these unfamiliar places, they may be more susceptible to things like predation. Throughout the annual cycle, the migration period is a time when these birds experience the greatest mortality.”

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Forest Fragments Act Like ‘Convenience Stores’ for Migrating Birds, Study Finds

Audubon  online


In a study published in PNAS in January, Guo and her colleagues set out to do just that. Using weather radar, the team identified the most popular stopover sites for migratory songbirds—areas where they can rest and refuel before resuming their energy-intensive journeys—throughout the eastern United States. The researchers chose to focus on eastern migratory landbirds because those populations see the largest declines among North American migrants during their travels.

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Birds Tell Us About Migration

Audubon  online


To unlock these mysteries, the team of biologists, led by Jeff Buler, PhD, Professor of Wildlife Ecology at University of Delaware, captured 169 individuals earlier this year and outfitted them with tiny transmitters that communicate with a network of monitoring stations called the Motus Wildlife Tracking System.

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Weather radar is key to bird-friendly wind energy

Anthropocene Magazine  online


“This is much farther than has been considered before when making recommendations about siting wind turbines to avoid such bird concentrations,” says study team member Jeff Buler, a wildlife ecologist at the University of Delaware in Newark. Currently, the U.S. Fish and Wildlife Service suggests an exclusion zone of 3 miles, while the Nature Conservancy recommends 5 miles.

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A New Golden Age of Observation Is Revealing the Wonders of Night Migration

Audubon  online


Even for those who study migration, the story is unfolding in ways never before possible. “The more you can see what’s going on, the more fascinating it becomes,” says Jeffrey Buler, a University of Delaware wildlife ecologist. “And we’re making new discoveries all the time.”

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How light pollution lures birds into urban areas during fall migration

Phys.org  online


On their fall migration south in the Northern Hemisphere, scores of birds are being lured by artificial light pollution into urban areas that may be an ecological trap, according to the University of Delaware's Jeff Buler.

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Blinded by the light: Birds lured into ecological traps by light pollution

United Press International  online


"Shortly after sunset, at around civil twilight, they all take off in these well-synchronized flights that show up as a sudden bloom of reflectivity on the radar," Jeff Buler, an ecologist at the University of Delaware, said in a news release. "We take a snapshot of that, which allows us to map out where they were on the ground and at what densities. It basically gives us a picture of their distributions on the ground."

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The New Migration Science

All About Birds  online


Jeff Buler, the director of the University of Delaware’s “Aeroecology” Program, is using the very lowest beam of NEXRAD radar to catch birds just as they leave the ground for their nighttime flight—and thus identify the small patches of habitat where they’d spent the preceding day.

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Radar reveals bird pile up on shores of the Great Lakes

United Press International  online


"Our study justifies the high value of shoreline habitats for conservation of migratory bird populations in the Great Lakes region," Jeff Buler, a researcher at the University of Delaware, said in a news release. "It also emphasizes that the extent of stopover use in shoreline habitats is context-dependent."

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New study identifies bird migration stopover sites

Phys.org  online


"In the Northeast, nothing provides more comprehensive coverage of the land surface than radar," said Jeff Buler, associate professor of wildlife ecology at the University of Delaware who led the study. "It detects birds over more than a third of the land area in the Northeast."

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Articles (10)

Relating weather radar data to migrating waterfowl abundance in the Rainwater Basin of Nebraska

The Journal of Wildlife Management

2023 Waterfowl migrations are large-scale events that involve millions of birds moving over broad geographic extents, which make them difficult to quantify and study. Historically, wildlife managers have relied mostly on field surveys, such as visual counts from the ground or air that sample at small spatial or temporal extents, or both. Combining field surveys with remote sensing data comprehensively collected over large spatial extents at high temporal frequency may improve the study of migrating waterfowl distributions.

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Autumn stopover hotspots and multiscale habitat associations of migratory landbirds in the eastern United States

Proceedings of the National Academy of Sciences

2022 Understanding the en route habitat requirements of migratory birds is critical for conservation but difficult to know at a large scale. We mapped stopover density of landbirds during autumn migration for the eastern United States using radar data. At a coarse scale, we found that birds migrate across a relatively broad front, underscoring the importance of widespread, locally based conservation efforts. At finer scales, we identified stopover hotspots that consistently support high densities of migrants. We demonstrate that forests provide the most important habitats for autumn migrants and that deciduous forest fragments in heavily deforested regions support especially high densities of migrants.

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Repurposing open-source data from weather radars to reduce the costs of aerial waterbird surveys

Ecological Solutions and Evidence

2022 Aerial counts are the primary means of monitoring waterbird populations. A valid population assessment requires a significant proportion of the population to be surveyed. For broad-ranging species, this requires costly reconnaissance flights and surveys over large areas of potential habitat.

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Using weather radar to help minimize wind energy impacts on nocturnally migrating birds

Conservation Letters

2022 As wind energy rapidly expands worldwide, information to minimize impacts of this development on biodiversity is urgently needed. Here we demonstrate how data collected by weather radar networks can inform placement and operation of wind facilities to reduce collisions and minimize habitat-related impacts on nocturnally migrating birds. We found over a third of nocturnal migrants flew through altitudes within the rotor-swept zone surrounding the North American Great Lakes, a continentally important migration corridor.

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Bird Migration at the Edge – Geographic and Anthropogenic Factors but Not Habitat Properties Drive Season-Specific Spatial Stopover Distributions Near Wide Ecological Barriers

Frontiers in Ecology and Evolution

2022 Stopping-over is critical for migrating birds. Yet, our knowledge of bird stopover distributions and their mechanisms near wide ecological barriers is limited. Using low elevation scans of three weather radars covering 81,343 km2, we quantified large-scale bird departure patterns during spring and autumn (2014–2018) in between two major ecological barriers, the Sahara Desert and Mediterranean Sea. Boosted Regression Tree models revealed that bird distributions differed between the seasons, with higher densities in the desert and its edge, as well as inland from the sea, during spring and a predominantly coastal distribution in the autumn.

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Winds aloft over three water bodies influence spring stopover distributions of migrating birds along the Gulf of Mexico coast


2021 Migrating birds contend with dynamic wind conditions that ultimately influence most aspects of their migration, from broad-scale movements to individual decisions about where to rest and refuel. We used weather surveillance radar data to measure spring stopover distributions of northward migrating birds along the northern Gulf of Mexico coast and found a strong influence of winds over nonadjacent water bodies, the Caribbean Sea and Atlantic Ocean, along with the contiguous Gulf of Mexico. Specifically, we quantified the relative influence of meridional (north–south) and zonal (west–east) wind components over the 3 water bodies on weekly spring stopover densities along western, central, and eastern regions of the northern Gulf of Mexico coast.

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Using the California Waterfowl Tracker to Assess Proximity of Waterfowl to Commercial Poultry in the Central Valley of California

Avian Diseases

2021 Migratory waterfowl are the primary reservoir of avian influenza viruses (AIV), which can be spread to commercial poultry. Surveillance efforts that track the location and abundance of wild waterfowl and link those data to inform assessments of risk and sampling for AIV currently do not exist. To assist surveillance and minimize poultry exposure to AIV, here we explored the utility of Remotely Sensed Moderate Resolution Imaging Spectroradiometer (MODIS) satellite imagery in combination with land-based climate measurements (e.g., temperature and precipitation) to predict waterfowl location and abundance in near real-time in the California Central Valley (CCV), where both wild waterfowl and domestic poultry are densely located.

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Light pollution is greatest within migration passage areas for nocturnally-migrating birds around the world

Scientific Reports

2018 Excessive or misdirected artificial light at night (ALAN) produces light pollution that influences several aspects of the biology and ecology of birds, including disruption of circadian rhythms and disorientation during flight. Many migrating birds traverse large expanses of land twice every year at night when ALAN illuminates the sky. Considering the extensive and increasing encroachment of light pollution around the world, we evaluated the association of the annual mean ALAN intensity over land within the geographic ranges of 298 nocturnally migrating bird species with five factors: phase of annual cycle, mean distance between breeding and non-breeding ranges, range size, global hemisphere of range, and IUCN category of conservation concern.

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A place to land: spatiotemporal drivers of stopover habitat use by migrating birds

Ecology Letters

2020 Migrating birds require en route habitats to rest and refuel. Yet, habitat use has never been integrated with passage to understand the factors that determine where and when birds stopover during spring and autumn migration. Here, we introduce the stopover-to-passage ratio (SPR), the percentage of passage migrants that stop in an area, and use 8 years of data from 12 weather surveillance radars to estimate over 50% SPR during spring and autumn through the Gulf of Mexico and Atlantic coasts of the south-eastern US, the most prominent corridor for North America’s migratory birds. During stopovers, birds concentrated close to the coast during spring and inland in forested landscapes during autumn, suggesting seasonal differences in habitat function and highlighting the vital role of stopover habitats in sustaining migratory communities.

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Artificial light at night confounds broad-scale habitat use by migrating birds

Ecology Letters

2018 With many of the world's migratory bird populations in alarming decline, broad-scale assessments of responses to migratory hazards may prove crucial to successful conservation efforts. Most birds migrate at night through increasingly light-polluted skies. Bright light sources can attract airborne migrants and lead to collisions with structures, but might also influence selection of migratory stopover habitat and thereby acquisition of food resources. We demonstrate, using multi-year weather radar measurements of nocturnal migrants across the northeastern U.S., that autumnal migrant stopover density increased at regional scales with proximity to the brightest areas, but decreased within a few kilometers of brightly-lit sources.

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Education (3)

The University of Southern Mississippi: PhD, Biology 2006

Louisiana State University: MS, Wildlife 1999

St. Mary’s College of Maryland: BA, Biology 1995

Affiliations (7)

  • American Ornithological Society
  • Association of Field Ornithologists
  • Wilson Ornithological Society
  • The Wildlife Society
  • Midwest Migration Network : Steering Committee Member
  • Gulf of Mexico Avian Monitoring Network
  • Delaware Ornithological Society