The Kootenai River is a beautiful, large mountain river and an outstanding site for viewing bald eagles, nesting osprey, great blue herons, and waterfowl. On the east bank of David Thompson Bridge just below the powerhouse, watch bald eagles and osprey diving for fish and returning to nearby snags; there are more than 20 nests between Libby and the dam. In the fall, bald eagles swarm below the dam to catch kokanee salmon. Over 160 bald eagles have been sighted in a day. Eagle migration starts in October, peaks in the middle of November, and tapers off near the end of December. The river is regulated by Libby Dam, which supplies water from 90-mile-long Lake Koocanusa. Besides offering a prime trout fishery, the river area affords viewing opportunities for eagles, osprey, deer, and mountain sheep. Three islands are located 2.5 miles down river from Libby that are used by ducks and geese during migrations.