The common merganser (North American) or goosander (Eurasian) (Mergus merganser) is a large duck of rivers and lakes in forested areas of Europe, northern and central Asia, and North America. It eats fish and nests in holes in trees. John James Audubon also used the name "Buff-breasted Merganser" (in addition to "goosander") in his book The Birds of America.