Historically, both Whistling and Trumpeter swans (Olor columbianus and O. buccinator) wintered in southwestern Washington and on the Columbia River. Lewis and Clark reported an abundant swan population and noted the difference in the abundance of the two species (Allen, P., History of the expedition under the command of Captains Lewis and Clark to the sources of the Missouri, thence across the Rocky Mountains down the River Columbia to the Pacific Ocean, performed during the years 1804-1805-1806. By order of the Gov. of U. S., Bradford and Inkeep, Phil. 2, 1814).