Anas obscura; Print; The American black duck (Anas rubripes) is a large dabbling duck in the family Anatidae. It was described by William Brewster in 1902. It is the heaviest species in the genus Anas; weighing 720-1; 640 g (1.59-3.62 lb) on average and measuring 54-59 cm (21-23 in) in length with a 88-95 cm (35-37 in) wingspan. It somewhat resembles the female mallard in coloration; but has a darker plumage. The male and female are generally similar in appearance; but the male's bill is yellow while the female's is dull green with dark marks on the upper mandible. It is native to eastern North America. During the breeding season; it is usually found in coastal and freshwater wetlands from Saskatchewan to the Atlantic in Canada and the Great Lakes and the Adirondacks in the United States. It is a partially migratory species; mostly wintering in the east-central United States; especially in coastal areas.; 1700-1880