The drake of this large, fish-eating bird has a long, thin, pointed, bright red bill, a dark green head, a black back and white chest, flanks and belly. The hen has a brown head with a crest, white chin and breast patches and a gray body. The drakes show no white on the head. Common Mergansers, Mergus merganser, have a long slender appearance in flight.
This species is larger than the red-breasted merganser, and is one of the largest of our ducks. It is one of the last to migrate south, and is more common than the red-breasted merganser on inland waters. Flocks move in "follow the leader" style, low over the water.
Length: 25 1/2"
Weight: 2 1/2 lbs.
The only call seems to be a startled croak.