For nearly 30 years, Sacajawea Audubon Society has helped coordinate the annual fall Bridger Mountains Raptor Survey in partnership with HawkWatch International (HWI). A total of 17 raptor species are recorded each season, including Golden & Bald Eagles, as well as many species of hawks and falcons. The migrants originate primarily from breeding locales in western Canada and Alaska. Their destinations include a wide range of latitudes (varying by species and population), from the American West & Mexico all the way to Central and South America.
Golden Eagles and the Bridger Range Flyway
The Bridger Range 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.
Recent Golden Eagle counts in the Bridgers have varied from 1,000 to 1,800 per season, with up to 250 or more on a peak migration day (generally during the first two weeks of October). However, it is noteworthy that counts of Golden Eagles at this and other western sites have shown steady declines from 2000 through 2010. Importantly, however, counts have stabilized and even increased slightly over the past 7 years.
The cause of this decline is not fully understood, but these findings have stimulated additional research, which is ongoing.This annual count scientifically assesses the status and long-term trends of Golden Eagles and other raptors using this Rocky Mountain flyway. The project also monitors landscape-level environmental changes, using these apex predators as insightful barometers of ecological health.
The Count
The count is conducted every day (weather permitting) from August 27th through October 31st. The best overall raptor viewing atop the Bridgers is from mid-September through mid-October. From the parking area above the Bridger Bowl Ski Area facilities it is a strenuous 1.5-2 hour hike to the observation point (elevation gain is 2,200 feet). The public is always welcome.
The Bridger Mountains Raptor Survey – History
Over 40 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. This set the stage for HawkWatch International (HWI) beginning standardized counts in 1991.
For more information
Check out the complete count numbers on the Bridger Mountains Raptor Survey here.
Check out the Bridger Hawk Watch Facebook Page.