White-tailed ptarmigan cover. The white-tailed ptarmigan was introduced into the Sierra Nevada of California, Wallowa Mountains in Oregon, and Uinta Mountains of Utah in the 1970s. It may have been native here during the early Pleistocene but became locally extinct due to climate changes with greater snow-cover in spring impacting on its breeding season. Alternatively, it may have been unable to colonize the Sierra Nevada because of the barriers provided by the Columbia River and the Great Basin, and the low altitudes of the intervening South Cascades. This herbivorous bird's diet varies seasonally. Nitrogen-rich snow buttercup leaves are favored in the spring
Arctic ground squirrel Arctic ground squirrel The Arctic ground squirrel ("Urocitellus parryii") is a species of ground squirrel native to the Arctic. People in Alaska, particularly around the Aleutians, refer to them as "parka" (pronounced "par'kee") squirrels, most likely because their pelt is good for the ruff on parkas and for clothing. Subspecies listed alphabetically. The Arctic ground squirrel has a beige and tan coat with a white-spotted back. This squirrel has a short face, small ears, a dark tail and white markings around its eyes. Arctic ground squirrels undergo a coat change from summer to winter. Summer coats include red/yellow colorations along