The Refuge is home to many species of wildlife. Sixty species of mammals and more than 235 species of birds have been observed on the Refuge. Bird watching provides opportunities to see many northern prairie grassland species such as western meadowlarks, mountain plovers, chestnut-collared longspurs, and prairie falcons. In winter bald eagles congregate near the open water below Fort Peck Dam. A refuge Bird List is available at any refuge office.
Large ungulates such as elk, mule deer, pronghorn, and bighorn sheep are common, while native predators like coyote, bobcat, and mountain lion are secretive and not commonly seen. The very popular Slippery Ann Elk Viewing Area is located on the west end of the Refuge along the Auto Tour Route. During the elk breeding season in September and October, large numbers of elk congregate here and provide visitors with a unique and exciting experience.