Species: Aythya valisineria

H - >2,500,000 square km (greater than 1,000,000 square miles) - H - BREEDS: central Alaska, central Yukon, northern Northwest Territories (Mackenzie Delta), and southeastern Manitoba south to northern California, western Nevada, northern Utah, northern Colorado, Nebraska, and Minnesota. WINTERS: southern British Columbia, northwestern Montana, northern Colorado, northern Tennessee to eastern Great Lakes, Chesapeake Bay, eastern Massachusetts, and Quebec, south to central Mexico, Gulf states, northern Florida; rarely Hawaii. In the U.S., the highest winter densities occur in the Chesapeake Bay region and at the Bitter Lake NWR in eastern New Mexico (Root 1988). Over 25% of the continental population winters in Louisiana. Winter populations in the Atlantic flyway are more concentrated than those in Mississippi flyway (Serie et al. 1983). About 83% of the western North American population overwinters for 4-6 months in California, primarily in San Francisco Bay (Reinecker, 1985, Calif. Fish Game 71:141-149).