Species: Aythya collaris

H - >2,500,000 square km (greater than 1,000,000 square miles) - H - BREEDS: southeastern and east-central Alaska, central British Columbia eastward through northern Saskatchewan to Newfoundland, south to northeastern California, southeastern Arizona, southern Colorado, Iowa, Illinois, Pennsylvania (formerly), northern New York, Massachusetts. WINTERS: southeastern Alaska, southwestern U.S., southern Illinois, and Massachusetts south through Mexico to Panama, Grenada, West Indies; rarely Hawaii. (AOU 1983). In the U.S., the highest winter densities occur in eastern New Mexico (Bitter Lake refuge), the Mississippi River in Mississippi, Lake Isom and Reelfoot refuges (Missouri-Tennessee), the Florida panhandle (St. Marks refuge), eastern Texas panhandle, and southern San Joaquin Valley in California (Root 1988).