Guide to North American Birds

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Adult and nestlings. Photo: Shiv's fotografia/Wikimedia (CC-BY-SA-4.0)

Great Cormorant

Phalacrocorax carbo

Widespread in the Old World, the Great Cormorant was once an uncommon and local breeder in a limited area of eastern Canada. In recent decades its North American population has gone through a great increase and expansion, with the nesting range now extending south into New England.

Conservation status	In recent decades, North American population has increased dramatically, and breeding range has expanded southward along coast.
Family	Cormorants
Habitat	Sea cliffs (nesting); mainly coastal. In North America mostly over shallow waters close to shore, especially in sheltered bays, rarely well out to sea. Nests on rocky cliffs of coasts and islands. Southerly wintering birds often around rock jetties. In recent years, as population has increased, has been found in winter on large rivers inland. In Old World regularly far inland on lakes, rivers, swamps.

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Feeding Behavior

See family introduction. Most foraging is within 10' of surface, although can dive to 30'.

Eggs

3-5, rarely 1-6. Pale blue-green, becoming nest-stained. Incubation is by both sexes, 28-31 days. Young: Both parents feed young, by regurgitation. Age at first flight about 50 days; young may return to nest to be fed for another 40-50 days.

Young

Both parents feed young, by regurgitation. Age at first flight about 50 days; young may return to nest to be fed for another 40-50 days.

Diet

Fish. Feeds almost entirely on fish, with small numbers of crustaceans, marine worms. In Old World, where found also on fresh water, diet may be more varied.

Nesting

Usually first breeds at age of 4-5 years. Breeds in colonies. Male chooses nest site, and displays to attract female by waving wings up and down, flashing white rump patches. Pairs at nest display by writhing and intertwining necks. Nest: Site is usually on sheltered ledge of cliff, from just above water to 300' or higher. Rarely nests in trees in North America (but does so commonly in Old World). Nest is a pile of sticks, seaweed, debris, lined with finer materials. Female does most building, with material brought by male.

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

Migration

Migrates in flocks. Migration parallels the coastline, usually a short distance offshore. Rarely strays inland in fall and winter.

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Migration

Migrates in flocks. Migration parallels the coastline, usually a short distance offshore. Rarely strays inland in fall and winter.

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

Songs and Calls

Deep guttural grunts.

Audio © Lang Elliott, Bob McGuire, Kevin Colver, Martyn Stewart and others.
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How Climate Change Will Reshape the Range of the Great Cormorant

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 facing the Great Cormorant

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.