Mentasta Caribou Herd Monitoring and Calf Recruitment Research

AITRC works with Cheesh’na Tribal Council and Wrangell-St. Elias National Park and Preserve to monitor the Mentasta Caribou Herd and better understand population dynamics, calf presence, and calf recruitment. By combining GPS collar data, aerial surveys, and game camera, this project provides information needed to understand factors affecting the herd and support informed management of this important subsistence resource.

Funded by the U.S. Fish and Wildlife Service Tribal Wildlife Grants Program and the Bureau of Indian Affairs, in partnership with Cheesh’na Tribal Council and Wrangell-St. Elias National Park and Preserve

About the Mentasta Caribou Herd.

The Mentasta Caribou Herd ranges across portions of the upper Copper River Basin, including areas within and surrounding Wrangell-St. Elias National Park and Preserve. The Mentasta herd has remained at a relatively low population density for more than 30 years. Understanding why the herd remains at these levels requires looking at multiple factors, including adult survival, calf production and survival, habitat, nutrition, and interactions with predators.

AITRC’s monitoring helps build a clearer picture of how the herd is changing over time and provides relevant information that can contribute to long-term stewardship.

Caribou Collaring & GPS Monitoring.

GPS and radio collars allow researchers to follow individual caribou across a large and remote landscape. GPS-collared adult females provide an important source of information for the project. AITRC supported fall 2024 capture and collaring efforts with WRST.

Aerial Surveys.

Because the Mentasta herd occupies a large and remote area, aircraft are an essential research tool.

Researchers used aerial telemetry and GPS locations to locate collared adult females and conduct repeated observations during important periods of the caribou life cycle. During the spring calving season, these flights can document whether adult females have calves and whether those calves remain with them during subsequent surveys.

Repeated surveys provide information that cannot be obtained from GPS locations alone and help researchers evaluate calf presence, apparent persistence, and recruitment indicators; formal survival estimates require additional analytical assumptions.

Game Cameras.

AITRC adapted its original proposed plan of calf collaring to a less invasive approach of conducting aerial surveys during the spring calving period. In 2026, staff continued repeated aerial monitoring and additionally deployed 48 remote cameras in three 4-by-4 grids in calving areas identified using historical adult-female collar locations. Cameras document caribou and calf activity, potential predator presence, and timing of wildlife use. These observational approaches contribute useful recruitment indicators but do not replace individually monitored calf survival estimates.

Looking Forward.

Future Calf Monitoring. Additional calf capture or collaring may be considered if all required agency, animal-care, and field authorizations are obtained. The ongoing Tribal Wildlife Grant project is planned to continue through December 2027.