Common mergansers have a long, slender, serrated, red or orange bill with a wide base. Males have a green head, a mostly white body, and a black and gray back. Female has a gray body with a rusty head that is sharply defined against the white neck. Voice is a hoarse croaking car-r-r-r or rapid cackling notes. Mergansers are divers, and the legs are far back on the body; on land, the posture is upright.
Similar species both have larger crests: Red-breasted merganser males have gray sides, a dark chest and back, and a ragged crest; females have a pale rusty head with an indistinct border between rusty head and gray-white breast. Hooded merganser males have black and white head, crest, and back, with chestnut flanks; females are brown with rusty crest.
Habitat and Conservation
About 350 species of birds are likely to be seen in Missouri, though nearly 400 have been recorded within our borders. Most people know a bird when they see one — it has feathers, wings, and a bill. Birds are warm-blooded, and most species can fly. Many migrate hundreds or thousands of miles. Birds lay hard-shelled eggs (often in a nest), and the parents care for the young. Many communicate with songs and calls.