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Fall 2003 Technical Report
(385 kb PDF Document, requires Adobe Acrobat Reader 5.0 or newer to view)

1999-2003 Count Results

HWI began full-season, fall migration counts at this site in southwestern Montana in 1991, with standardized, single-site counts commencing in 1992. This ongoing effort monitors long-term trends in populations of raptors using this northern portion of the Rocky Mountain Flyway. More than twenty years ago, Fred Tilly discovered the Bridger Range to be an important fall flyway for raptors. He conducted limited migration counts at the site in 1979, 1980, and 1982 to set the stage for HWI beginning standardized counts in the 1990s. The count now occurs from a helicopter platform located atop the ridge above Bridger Bowl Ski Area, about 25 miles northeast of Bozeman, Montana. The flyway is noted for the largest concentration of Golden Eagles in the lower 48 states, with peak eagle activity (sometimes more than 200 eagles/day) in mid-October. Golden Eagle counts typically range from 1200-1900 birds per season. Up to 1,500 migrants of 17 additional species also may be seen each season, with Sharp-shinned Hawks, Cooper's Hawks, Red-tailed Hawks, Bald Eagles, and American Kestrels among the most commonly seen species. The project runs from 27 August to 31 October each year.

In 2003, HWI conducted or co-sponsored 14 long-term standardized migration counts in 10 states and Vercruz, Mexico. The information gathered in these studies enables us to better understand the life histories, ecology, status, and conservation needs of raptor populations in North America. Because raptors are top-level predators, occupy large home ranges, inhabit most ecosystems, and are sensitive to environmental contamination and other human disturbances, they serve as important biological indicators of ecosystem health. Moreover, due to the remoteness and widespread distribution of most raptor populations, migration counts likely represent the most cost-effective and efficient method for monitoring the regional status and trends of multiple raptor species. In addition to gathering important scientific data, the Bridger Mountains project provides opportunities for the public to learn about the ecology and conservation needs of raptors through on-site environmental interpretation for visitors. Education is the key to long-term success in securing public understanding and action on behalf of raptors and the ecosystems upon which we all rely.

To further promote awareness of the Bridger migration and raptor ecology and conservation needs, the locally organized Bridger Raptor Festival occurs each year during the fall-migration season.  The festival, which usually occurs in late September or early October, typically includes invited presentations on raptor research, ecology, and conservation at local venues, as well as ID seminars, live-bird programs, raffles, and field trips to the migration site from the Bridger Bowl Lodge.   The annual festival is organized by the Montana Raptor Center (formerly known as Big Sky Wildcare), Gallatin National Forest, Bridger Bowl, Museum of the Rockies, HWI, Wild Birds Unlimited, and the Bridger Outdoor Science School. Stay tuned to this site beginning in summer for current scheduling and program information.

Support for this project in 2003 was provided Gallatin National Forest, the Fanwood Foundation, New Belgium Brewing Co., Sacajawea Audubon Society, and HWI members.