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Bridger Mountains Raptor Migration Project
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 2009, the project was operated in partnership with Montana Audubon and HWI Founder Steve Hoffman. For more information, please visit Montana Audubon.
In 2009, HWI conducted or co-sponsored 10 long-term standardized migration counts in 7 states and Veracruz, 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. Stay tuned to this site beginning in summer for current scheduling and program information.
Funding for the 2009 project was provided by the USDA Forest Service–Gallatin National Forest, Bridger Bowl Ski Area, Sacajawea Audubon Society, Montana Audubon, Fanwood Foundation, Frank and Irmeli Smith, and Paul and Nancy Heymann. Special thanks to Randy Elliot of Bridger Bowl who provided essential logistical support and to Doug Wales for additional logistical support. We are also especially thankful for support provided by the Bridger to Bangtail Coalition in the form of housing and other logistical support provided to our two official observers. Special thanks to Candace Hamlin, Deb Strattford, and Johnnie Corrie for their help arranging for and providing the local cabin the crew lived in during the season. We also thank Jeff Pentel, Matt Keefer, Lisa Baril, John Parker, John Bell, and Mark Donahue for their observational and/or logistical assistance.
