Deanna Dawson is a research wildlife biologist at the USGS Patuxent Wildlife Research Center. An experienced field ornithologist, her current research uses remote sensing techniques to sample the spatiotemporal distribution of birds, primarily during migration periods. She collaborates in research that analyzes data from weather surveillance radars to map the densities of nocturnal migrants at daytime stopover sites, and uses acoustic data to quantify and model the abundance of migrants aloft. She also works on methods to estimate animal densities from sounds recorded on microphone arrays, applying them to recordings of bird song made across the Patuxent Research Refuge during the nesting season.
Science and Products
The Challaenge: Each autumn, millions of landbirds migrate southward from breeding areas in the U.S. and Canada. Because these migrations occur during hurricane season, the impacts of hurricanes on migrating birds and their en route resting and foraging sites (stopover sites) are a real concern. Hurricane Sandy occurred late in the landbird migration season. By the time the storm made landfall in late October 2012, most birds that migrate to tropical wintering areas had already passed through the Mid-Atlantic region. However, the storm likely impacted temperate migrants that winter in Mid-Atlantic coastal habitats or were en route to wintering areas in the southern U.S. We applied a variety of techniques and data to assess possible impacts of Hurricane Sandy on the movement of nocturnally migrating landbirds: weather surveillance radar data, field surveys and eBird citizen science data, and dynamic simulation of migratory flights using an individual-based model (IBM) together with high-resolution modeled wind data.
The Challenge: Concerns have arisen about the potential impacts of wind power development in the Appalachians on migrating birds, creating a critical need for information on their distribution and flight characteristics as they pass through the region. This study focuses on the spatial and temporal distribution of nocturnally migrating birds in the Central Appalachians (MD, VA, WV). The overall objective is to increase our understanding of bird migration through the region, so that informed and scientifically sound recommendations can be made to reduce the risk to migrating birds of wind power projects.
The Challenge: Most landbird conservation efforts focus on protecting or enhancing breeding habitat. For migratory species, however, mortality is highest during the biannual migration periods. In fall, juvenile birds are making their first migratory flights; their success, and that of adult birds, depends on availability of suitable sites to safely rest and forage. Identifying important stopover sites and habitats is thus a critical step to develop comprehensive conservation plans for migratory landbirds. We used weather surveillance radar data from Fall 2008–2014 to model and map the spatial distribution of landbird migrants at stopover sites across the northeastern U.S.
Artificial light at night confounds broad-scale habitat use by migrating birds
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,...McLaren, James D.; Buler, Jeffrey J.; Schreckengost, Tim; Smolinsky, Jaclyn A.; Boone, Matthew; van Loon, E. Emiel; Dawson, Deanna K.; Walters, Eric L.
Density-dependent home-range size revealed by spatially explicit capture–recapture
The size of animal home ranges often varies inversely with population density among populations of a species. This fact has implications for population monitoring using spatially explicit capture–recapture (SECR) models, in which both the scale of home-range movements σ and population density D usually appear as parameters, and both...Efford, M.G.; Dawson, Deanna K.; Jhala, Y.V.; Qureshi, Q.
Radar analysis of fall bird migration stopover sites in the northeastern U.S.
The national network of weather surveillance radars (WSR-88D) detects flying birds and is a useful remote-sensing tool for ornithological study. We used data collected during fall 2008 and 2009 by 16 WSR-88D radars in the northeastern U.S. to quantify the spatial distribution of landbirds during migratory stopover. We geo-referenced estimates...Buler, Jeffrey J.; Dawson, Deanna K.
Occupancy in continuous habitat
The probability that a site has at least one individual of a species ('occupancy') has come to be widely used as a state variable for animal population monitoring. The available statistical theory for estimation when detection is imperfect applies particularly to habitat patches or islands, although it is also used for arbitrary plots in...Efford, Murray G.; Dawson, Deanna K.
Cerulean Warbler Technical Group: Coordinating international research and conservation
Effective conservation for species of concern requires interchange and collaboration among conservationists and stakeholders. The Cerulean Warbler Technical Group (CWTG) is a consortium of biologists and managers from government agencies, non-governmental organizations, academia, and industry, who are dedicated to finding pro-active, science-based...Dawson, D.K.; Wigley, T.B.; Keyser, P.D.
Multi-species occurrence models to evaluate the effects of conservation and management actions
Conservation and management actions often have direct and indirect effects on a wide range of species. As such, it is important to evaluate the impacts that such actions may have on both target and non-target species within a region. Understanding how species richness and composition differ as a result of management treatments can help determine...Zipkin, E.F.; Andrew, Royle J.; Dawson, D.K.; Bates, S.
Population density estimated from locations of individuals on a passive detector array
The density of a closed population of animals occupying stable home ranges may be estimated from detections of individuals on an array of detectors, using newly developed methods for spatially explicit capture–recapture. Likelihood-based methods provide estimates for data from multi-catch traps or from devices that record presence without...Efford, Murray G.; Dawson, Deanna K.; Borchers, David L.
Effect of distance-related heterogeneity on population size estimates from point counts
Point counts are used widely to index bird populations. Variation in the proportion of birds counted is a known source of error, and for robust inference it has been advocated that counts be converted to estimates of absolute population size. We used simulation to assess nine methods for the conduct and analysis of point counts when the data...Efford, Murray G.; Dawson, Deanna K.
Bird population density estimated from acoustic signals
Many animal species are detected primarily by sound. Although songs, calls and other sounds are often used for population assessment, as in bird point counts and hydrophone surveys of cetaceans, there are few rigorous methods for estimating population density from acoustic data. 2. The problem has several parts - distinguishing individuals,...Dawson, D.K.; Efford, M.G.
Effects of habitat change along Breeding Bird Survey routes in the central Appalachians on Cerulean Warbler population
The cerulean warbler (Dendroica cerulea) is one of the highest priority bird species in the eastern United States because populations have declined 4.3% annually during 1966?2005 based on Breeding Bird Survey (BBS) data. Habitat loss and fragmentation due to land use changes is thought to be one of the major factors contributing to the decline....McElhone, P.; Wood, P.W.; Dawson, D.
Applying radar technology to migratory bird conservation and management: Strengthening and expanding a collaborative
Executive Summary Understanding the factors affecting migratory bird and bat populations during all three phases of their life cycle—breeding, nonbreeding, and migration—is critical to species conservation planning. This includes the need for information about these species’ responses to natural challenges, as well as information...Ruth, Janet M.; Ruth, Janet M.; Manville, Albert; Larkin, Ron; Barrow, Wylie C.; Johnson-Randall, Lori; Dawson, Deanna K.; Diehl, Robert H.; Wang, Yufang; Sojda, Richard S.; Angryk, Rafal; Klaver, Robert W.; Mead, Reggie; Paxton, John; Heglund, Patricia; Kirsch, Eileen; Suarez, Manuel J.; Robinson, Larry; Gauthreaux, Sidney A.; Belser, Carroll G.; Franke, Steven J.; Bruderer, Bruno; Buler, Jeffrey J.; Moore, Frank R.; Mizrahi, David S.; Fogg, Robert; Kelly, T. Adam; Cryan, Paul; Crum, Tim; Schuur, Terry J.; Krueper, Dave; Diehl, Robb; Will, Tom
Identifying stopover sites for migrating passerine birds in the lower Chesapeake Ba y region
Stopover sites in the Lower Chesapeake Bay region, used in autumn by passerine birds that migrate nocturnally, are being identified from radar images (WSR-88D/NEXRAD, Wakefield, V A, and NPOL, a higher resolution radar installed at Oyster, V A). Radar images from the hour after sunset 'capture' birds as they leave stopover sites to resume their...Mabey, S.; Watts, B.; Paxton, B.; Smith, F.; Truitt, B.; Dawson, D.