Guide to North American Birds
Conservation status Has declined seriously in southern part of breeding range, mostly owing to loss of habitat. Still numerous as a breeder in parts of Canada. Vulnerable because of its reliance on large marshes. Acid rain may reduce food supplies in some areas.
Family Herons, Egrets, Bitterns
Habitat Marshes, reedy lakes. Breeds in freshwater marshes, mainly large, shallow wetlands with much tall marsh vegetation (cattails, grasses, sedges) and areas of open shallow water. Winters in similar areas, also in brackish coastal marshes. Sometimes feeds in dry grassy fields.
Extensive freshwater marshes are the favored haunts of this large, stout, solitary heron. It is seldom seen as it slips through the reeds, but its odd pumping or booming song, often heard at dusk or at night, carries for long distances across the marsh.

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Feeding Behavior

Forages mostly by standing still at edge of water, sometimes by walking slowly, capturing prey with sudden thrust of bill. May forage at any time of day or night, perhaps most actively at dawn and dusk.


Eggs

3-5, sometimes 2-7. Pale brown to olive-buff. Incubation is by female only, 24-28 days. Young: Evidently only female cares for young, feeding them by regurgitation of partly-digested items. Young may leave nest after 1-2 weeks, but remain nearby and are fed up to age of 4 weeks. Age at first flight unknown, possibly 7-8 weeks.


Young

Evidently only female cares for young, feeding them by regurgitation of partly-digested items. Young may leave nest after 1-2 weeks, but remain nearby and are fed up to age of 4 weeks. Age at first flight unknown, possibly 7-8 weeks.

Diet

Mostly fish and other aquatic life. Eats fish (including catfish, eels, killifish, perch), frogs, tadpoles, aquatic insects, crayfish, crabs, salamanders, garter snakes. Has been seen catching flying dragonflies. In drier habitats may eat rodents, especially voles.


Nesting

Male defends nesting territory by advertising presence with "booming" calls. Courtship displays not well known; male may hold head low and fluff out white feathers on sides. One male may mate with two or three females. Nest: Site is usually in dense marsh growth above shallow water, sometimes on dry ground among dense grasses. Nest (apparently built by female alone) is a platform of grasses, reeds, cattails, lined with fine grasses.

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

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Migration

May be permanent resident in a few areas at southern edge of breeding range but most are migrants. Some winter south to West Indies, Central America. May migrate mostly at night.

  • 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

On breeding grounds, a loud pumping sound, oong-KA-chunk! repeated a few times and often audible for half a mile. Flight call a low kok-kok-kok.
Audio © Lang Elliott, Bob McGuire, Kevin Colver, Martyn Stewart and others.
Learn more about this sound collection.

How Climate Change Will Reshape the Range of the American Bittern

Audubon’s scientists have used 140 million bird observations and sophisticated climate models to project how climate change will affect this bird’s range in the future.

Zoom in to see how this species’s current range will shift, expand, and contract under increased global temperatures.

Climate Threats Near You
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Climate threats facing the American Bittern

Choose a temperature scenario below to see which threats will affect this species as warming increases. The same climate change-driven threats that put birds at risk will affect other wildlife and people, too.