Elk, bobcat, mountain lion, coyote, yellow-bellied marmot, red fox and cottontail rabbit are a few of the mammal wildlife species at Ridgway. Mule deer often graze through the campgrounds at any time of year. Black bear mainly inhabit higher, more alpine environments but occasionally enter the park when food sources are scarce. The western side of the reservoir is particularly good habitat for reptile species, such as sagebrush lizard, short-horned lizard and collared lizard.
More than 140 species of migratory and resident birds have been identified in the park, including many species of waterfowl and shorebirds attracted to the reservoir. Confirmed breeders in the park include the American dipper, black-chinned hummingbird, red-naped sapsucker, white-throated swift, red-tailed hawk and many others. Northern harrier and osprey are common raptors, and Northern goshawks and American Peregrine falcons have been observed as well. Bald eagles winter in the Uncompahgre Valley from November to April while golden eagles are year-round residents.
Anglers on the reservoir and in-flowing streams fish for rainbow trout, brown trout, Kokanee salmon and the occasional yellow perch. At the south end of the reservoir there is a snagging season for Kokanee trout beginning in September and continuing until the end of the year. Crayfish are also abundant in the reservoir. In the tailwaters below the dam, rainbow trout, brown trout and cutthroat trout challenge fly fishermen in all seasons of the year. The two ponds in Pa-Co-Chu-Puk are stocked with rainbow trout for three youth fishing events held during the summer months.