Common Merganser

Common Merganser, male

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Common Merganser, female

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1. Description
2. Sound
3. Conservation Status
4. Other Names
5. Cool Facts
6. Full detailed species account

A large diving duck with a long thin bill, the Common Merganser is found along large lakes and rivers across the northern hemisphere. The long bill has toothy projections along its edges that help the duck hold onto its slippery fish prey.

Description

• Large, slender diving duck.
• Long, thin, orange bill.
• White patches in wing visible in flight.
• Male with bright white sides and iridescent green head.

• Size: 54-71 cm (21-28 in)
• Wingspan: 86 cm (34 in)
• Weight: 900-2160 g (31.77-76.25 ounces)

Sex Differences

Male boldly patterned with white sides, black back, and green head. Female dull gray with reddish head and white chin.

Sound

Silent except in courtship when male makes a hoarse croaking, a twanging sound, or a bell-like note. Female makes a harsh "gruk." Wings produce a rushing noise in flight.

Conservation Status

Populations appear stable.

Other Names

Grand Harle, Mergo mayor (French)
Goosander (English)

Cool Facts

• The Common Merganser usually nests in tree cavities, either those made by large woodpeckers or from where a limb broke off. It will also use a nest box. Infrequently a Common Merganser might make its nest in a rock crevice, a hole in the ground, a hollow log, in an old building, or in a chimney.
• Young Common Mergansers leave their nest hole within a day or so of hatching. The mother protects the chicks, but she does not feed them. They dive to catch all of their own food. They eat mostly aquatic insects at first, but switch over to fish when they are about 12 days old.

• Gulls of various species often follow flocks of foraging Common Mergansers. The gulls wait for the ducks to come to the surface with fish, and then they try to steal their prey. Occasionally even a Bald Eagle will try to steal a fish from a successful merganser.

Sources used to construct this page:

Mallory, M. and K. Metz. 1999. Common Merganser (Mergus merganser). In The Birds of North America, No. 442 (A. Poole and F. Gill, eds.). The Birds of North America, Inc., Philadelphia, PA.