The Common Merganser (Mergus merganser) is bigger than the mallard. The drake displays a dark green head and a discrete crest. Its beak is red, thin, and hooked, and its neck, chest, and body sides are black. Its wings are white except for the extremities that are black. Its tail and rump are grey. During the spring period of courtship, it displays more of a pink-tinted chest. The female and duckling common merganser have a brownish red head, white underparts, and greyish upperparts. The eclipsed drake is similar to the female except for the wing front feathers that are white.
This duck species is widespread in North America. It can be found in Canada, from east to west and from north to south, as well as in the United States. The common merganser migrates to the south: Northern Mexico, Southern California, Mexico Gulf or Florida.
The common merganser likes to nest close to soft water bodies: rivers, wide rivers, lakes, and large ponds. It builds its nest in hollow trees and in cliff holes. The female's nest is set up in a wide hollow tree, on an escarpment or on a bank and usually welcomes 8 to 12 cream white eggs between April and May. It sits on its eggs alone for 28 to 35 days. The ducklings are precocial and fly for the first time between their 60th and 70th day.