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Eighty-two volunteers counted 314 eagles across the Powder River Basin as part of the nationwide Midwinter Bald Eagle Survey on the morning of January 14, 2017.

Sightings included 198 bald eagles, 102 golden eagles, and 14 eagles of undetermined species. Several other raptor species were also observed, the most common being rough-legged hawks and red-tailed hawks.

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 2016 surveys found 300, 162, 269, 288, 290, 304, 310, 354, 407, and 547 eagles, respectively.  These survey totals vary due to the number of routes covered in each year, but are also influenced by weather and the availability of food sources including carrion, prairie dogs, and rabbits. Numbers of both golden and bald eagles decreased from last year, likely due to cold temperatures and heavy snow cover in the region. 

The BLM relies heavily on area volunteers to complete the survey, and once again had a high level of participation.  Volunteer support makes the midwinter survey a success, and many volunteers participate annually.  Volunteers range from young children to middle school students to retirees, and are essential to the survey effort, as noted by survey coordinator Charlotte Darling, “There is no way we could gather this amount of data without public participation and support.  I am so thankful for our volunteers’ efforts each year!”

The information gathered by the survey is used by wildlife researchers and managers nationwide, but is also valuable on the local level. The data collected helps the BLM to determine important habitats in the Buffalo Field Office, which consists of Campbell, Johnson, and Sheridan counties.

The national Midwinter Bald Eagle Survey effort 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.  A 25-year trend analysis paper covering the years 1986-2010 was published in the September 2015 issue of The Journal of Raptor Research.

Other regions of the state also participate in this annual survey.  Wildlife professionals from the BLM, USDA Forest Service, National Park Service, and U.S. Fish and Wildlife Service help coordinate local surveys in 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.

If you are interested in volunteering next year, or would like additional information, contact Charlotte Darling at 307-684-1045.  For more information on the national program and its results visit the U.S. Army Corps of Engineers Bird Initiative website at https://corpslakes.erdc.dren.mil/employees/bird/midwinter.cfm.