Birds & Science

We use the best available science to ensure the survival of Montana's birds and other wildlife.


Golden Eagle Migration Survey

Monitoring Golden Eagle and migratory raptor populations

The Golden Eagle Migration Survey (GEMS) is a collaborative, science-based effort to monitor the autumn migration of Golden Eagles and other raptors along the Big Belt Mountains of Montana.

The Big Belts is a 75-mile long, northwest-southeast trending ridgeline managed by the Helena, Lewis and Clark National Forest. The range is bordered to the west by Canyon Ferry Lake, a 35,181-acre artificial reservoir created by the damming of the Upper Missouri River. To the east of the Big Belts lies Shields Valley and farther east is another string of northwest-southeast trending mountain ranges. Following the Big Belt Mountains toward the south, southeast leads to the Bridger Mountains, where many of the raptors migrating through the Big Belt Mountains also likely pass. The Big Belts are part of a network of ten migration survey sites in western Montana north through Alberta.

Project partners have included Montana Audubon, US Forest Service and Montana Fish Wildlife and Parks.

The Big Belt Mountains were first recognized as a significant Golden Eagle migration flyway by Missoula-based Rob Domenech, with Raptor View Research Institute (RVRI) in 2007. Exploratory migration counts were conducted by Steve Hoffman, founder of HawkWatch International and former Executive Director of Montana Audubon, in October of 2014. Since 2015, Montana Audubon has supported annual migration surveys at Duck Creek Pass  Strong southwesterly winds typically prevail across the crest of the Big Belts. These consistent winds, combined with the Big Belts’ steep west-facing slopes, generate powerful orographic lift, thus providing ideal flying conditions for migrating raptors. The ‘lake-effect’ of Canyon Ferry Reservoir may enhance the consistency and speed of these westerly winds over the Big Belts. These factors, along with the prominent “leading line” created by the Rocky Mountain Front (which extends to the north well into Canada) make the southern end of the Big Belts a profoundly significant concentration point for migrating raptors in autumn. Thousands of Golden Eagles migrate south past the site each fall, with some October days seeing over three-hundred birds pass during survey hours. Please contact Amy Seaman ([email protected])  for more information about this project, and please check out our Big Belts site reports: 2016, 2017, 2018 and a short wrap-up, 2019.

Join us Tuesday September 15th – Thursday September 17th (10am and 4pm) for our online fundraiser and virtual raptor identification classes.

Registration is open now! For more information, click HERE.

2020 raptor identification and photography workshop- Saturday/Sunday, September 26th/27th  2020

2020 Bridger Raptor Fest – CANCELED!

Unfortunately, the popular Bridger Raptor Festival, an annual event held in and around Bozeman is canceled for 2020. The festival, which is free to the public, centers around a raptor migration count of the largest known Golden Eagle migration in the United States which takes place at the Bridger Bowl ski area in the Gallatin National Forest just north of Bozeman. The event is the first weekend in October, and we will be there in 2021 to share our raptor identification expertise with the community. We look forward to the return of this event!

Support Golden Eagle and raptor monitoring with a contribution here!



Join Our Online Network

By joining our online network, you will receive timely conservation updates, action alerts, legislative news, our monthly eNews, information about upcoming events and more.

Make an Online Donation & Support Our Efforts

Montana Audubon depends on your financial support to continue our ambitious conservation work around the state.

Take Action

Take action on timely conservation issues Montana Audubon is engaged with. Your help will protect Montana’s birds and other wildlife into the future.

Join Our Online Network

Get updated on the latest Audubon programs and initiatives

Montana Audubon - © Copyright 2020 All Rights Reserved