Guide to North American Birds
Conservation status Still widespread and numerous. Wintering concentrations would be vulnerable to oil spills and other types of pollution.
Family Ducks and Geese
Habitat Salt bays, ocean; in summer, lakes. In breeding season around lakes, ponds, and slow-moving rivers, generally in open country. In winter mainly on coastal waters, especially shallow water over shellfish beds; some remain on Great Lakes and other large bodies of fresh water.
The largest scoter. Flocks usually fly low over the sea in long, wavering lines, but in migration they may fly much higher, and a flock may suddenly drop hundreds of feet with a loud rushing noise. On the water, generally silent.

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Feeding Behavior

Forages by diving and swimming underwater, propelled mainly by feet, with wings partly spread to aid in maneuvering and thrust. Small items are swallowed underwater, but large mollusks are brought to surface and swallowed whole there.


Eggs

Usually 9-10, sometimes 6-12. Pale buff or pinkish. Incubation is by female only, 25-30 days. Female covers eggs with down when leaving nest. Young: Leave nest shortly after hatching. Female tends young and broods them while small, but young feed themselves. Age at first flight not well known, may be 9-11 weeks or as little as 7-8 weeks.


Young

Leave nest shortly after hatching. Female tends young and broods them while small, but young feed themselves. Age at first flight not well known, may be 9-11 weeks or as little as 7-8 weeks.

Diet

Mostly mollusks. In addition to mollusks, also feeds on crustaceans and aquatic insects, plus small numbers of fish. Also eats some plant material, including sea lettuce, pondweeds, and others.


Nesting

In courtship, several males may surround one female. Male displays include lowering head, arching back, and rushing forward short distance on water. Several males may pursue female on short underwater chases. Nesting activity begins late, with clutches often not complete until late June or early July. Nest site is on ground, usually close to water in patch of dense brush. On islands in lakes, several nests may be close together. Nest is shallow depression, sometimes with plant material added, lined with down.

Illustration © David Allen Sibley.
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Text © Kenn Kaufman, adapted from
Lives of North American Birds

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Migration

Generally migrates in small flocks, although large numbers may congregate at stopover points. On overland passage to coastal wintering areas, may fly very high. Adult males tend to winter somewhat farther north, on average, than females or younger birds.

  • All Seasons - Common
  • All Seasons - Uncommon
  • Breeding - Common
  • Breeding - Uncommon
  • Winter - Common
  • Winter - Uncommon
  • Migration - Common
  • Migration - Uncommon

See a fully interactive migration map for this species on the Bird Migration Explorer.

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Songs and Calls

Soft whistles and guttural croaks.
Audio © Lang Elliott, Bob McGuire, Kevin Colver, Martyn Stewart and others.
Learn more about this sound collection.