The males are noted for their fancy crests and the females for their demure dress and hole-nesting habits. They are not as numerous as the larger mergansers but are not really rare, and are usually found in sheltered bays, rivers and ponds rather than in the open waters of the Great Lakes favoured by the larger mergansers.
The long, low profile marks them as mergansers. The males with their large fan-shaped white crests, bordered with black, and their reddish sides and white breasts crossed by the black vertical stripes, are easily identified. At a distance the chunky males of the Buffleheads might be mistaken, but the different shape of both bird and crest should separate them easily. The females are very demurely dressed, with tan-coloured crests on a dark body, the crests usually depressed: notably inconspicuous birds.