Over 200 species of animals inhabit the river and its tributaries. Birds such as loons, grebes, ducks, kingfishers, and bald eagles are known to live around streams and other regions of the watershed. Auks, gulls, and terns have been spotted around the river's mouth, and black-legged kittiwakes nest in the area during the winter. The wildlife in the Kalmiopsis region of the Chetco watershed is more diverse than that of any other region in Oregon. Mammals such as American black bears, black-tailed deer, bobcats, ring-tailed cats, and gray foxes are common inhabitants of this region. The rare Siskiyou chipmunk is endemic to the Klamath Mountains. Steelhead and chinook and coho salmon are the most common anadromous fish that inhabit the Chetco River. Steelhead are abundant and have been spotted in most major and minor streams. Chinook salmon usually travel as far as Boulder Creek, about halfway between the Chetco's headwaters and its mouth. Coho also generally stay in this area, but some have been found in the Granite and Carter Creek area, about above Boulder Creek. Coastal cutthroat trout can be found all around the watershed; some migrate to the ocean, while others live in the river and its tributaries year round. Pacific lamprey, three-spined stickleback, and various sculpins have also been observed.