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Buffalo Field Office
Release Date: 03/20/12
Contacts: Lesley A. Elser    

Volunteers Count 306 Eagles during 2012 Midwinter Bald Eagle Survey

On January 14, 69 volunteers spent the morning searching for bald and golden eagles across the Powder River Basin. Their efforts were part of the nationwide midwinter bald eagle survey, coordinated locally by the Bureau of Land Management (BLM) Buffalo Field Office.

Statewide 2012 Bald Eagle Survey Results
Statewide 2012 Midwinter Bald Eagle Survey Results

Map of bald eagle sitings in the Powder River Basin.
Map of bald eagles sightings in the Powder
River Basin during
the 2012 survey.

Volunteers counted 180 bald eagles, 112 golden eagles, and 14 eagles of undetermined species along 1,340 miles of public roads on established survey routes. Several other raptor species were also sighted with the most common being rough-legged hawks and red-tailed hawks, and less common being northern goshawks, ferruginous hawks, and northern harriers. Single sightings of a prairie falcon, Swainson’s hawk, and snowy owl were also reported.

The midwinter bald eagle survey has been conducted in the Powder River Basin since 2006, with 119 eagles counted in that year. The 2007 through 2011 surveys found 300, 162, 269, 288, and 290 eagles, respectively. These survey totals vary due to the number of routes covered in each year, but were also influenced by weather and the availability of prey such as carrion, prairie dogs, and rabbits. Golden eagles observed during the 2012 survey showed a 40 percent increase from 2011. Bald eagle numbers were down compared to previous years. It is unknown why there was a shift in numbers seen in the Powder River Basin. The mild weather during the survey, warm temperatures and clear skies, likely increased eagle activity and visibility. Other explanations could include fluxes in prey populations or severe weather in surrounding regions.

In past years, bald eagle observations were concentrated in the foothills along Interstate 90 between Sheridan and Buffalo. In these areas, road kill, fish, and waterfowl provided valuable winter forage, while trees offered roosting sites where the eagles could keep warm at night. This year, while still concentrated in riparian areas, eagles were more widely distributed. “Bald eagles were not seen in as large of groups as previous years,” reports Darci Stafford, BLM Wildlife Biologist. “The mild weather the week prior to the survey likely caused bald eagles to redistribute away from communal roosts, and utilize more of the available habitat.”

While hundreds of bald and golden eagles are seen in the Basin during the winter months, only a few stay year-round. Approximately 10 to 12 bald eagle pairs nest in the area. A greater number of golden eagles remain in the Powder River Basin to breed. The winter populations migrate north in March and April, returning to northern Canada and Alaska.

Volunteers surveyed all 58 established routes this year. The BLM was especially thrilled to have such a great turnout from Campbell County, where it has been difficult to get routes covered in the past. “Volunteers are essential to the success of the midwinter survey,” said BLM Wildlife Technician Charlotte Darling. “Their participation helps wildlife managers monitor the Basin’s winter eagle population.” The information gathered from the survey will be used by wildlife researchers and managers nationwide, but it is also valuable on the local level. The data collected helps the BLM to determine important habitats in the Buffalo Field Office resource area, which consists of Campbell, Johnson, and Sheridan counties.

The national midwinter bald eagle survey began in 1979 as an effort to identify wintering habitat and develop a total population index for the struggling eagle population in the lower 48 states. Collecting eagle data over the long-term has allowed analyses of population trends that help to monitor the health of the species as a whole.

Other regions of the state participated in the survey as well, with many participating for the first time this year. Wildlife professionals from the BLM, USDA Forest Service, National Park Service, and U.S. Fish and Wildlife Service helped coordinate local surveys in the following BLM resource management areas, national forests, and national parks: Casper, Cody, Kemmerer, Lander, Newcastle, Pinedale, Rawlins, Rock Springs, and Worland BLM field offices, Bridger-Teton National Forest, Medicine Bow National Forest, Grand Teton National Park, and Yellowstone National Park. The BLM’s Cody and Worland field offices have been participating in the survey since the late 1980s, resulting in over 20 years of data that has been used in national population trend analyses.

If you are interested in volunteering next year, or would like additional information, contact Charlotte Darling at (307) 684-1045 or Darci Stafford at (307) 684-1144. For more information on the national program and its results visit the U.S. Army Corps of Engineers Bird Initiative website at

The BLM manages more than 245 million acres of public land, the most of any Federal agency. This land, known as the National System of Public Lands, is primarily located in 12 Western states, including Alaska. The BLM also administers 700 million acres of sub-surface mineral estate throughout the nation. The BLM's mission is to sustain the health, diversity, and productivity of America’s public lands for the use and enjoyment of present and future generations. In Fiscal Year 2015, the BLM generated $4.1 billion in receipts from activities occurring on public lands.

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Last updated: 03-20-2012