Great Cormorant
Great Cormorant
Phalacrocorax carbo
At a Glance
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.
All bird guide text and rangemaps adapted from by Kenn Kaufman漏 1996, used by permission of Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Category
Cormorants, Upright-perching Water Birds
IUCN Status
Least Concern
Habitat
Coasts and Shorelines, Open Ocean, Saltwater Wetlands
Region
Eastern Canada, Florida, Mid Atlantic, New England, Southeast
Behavior
Direct Flight, Formation, Soaring, Swimming
Population
1.400.000
Range & Identification
Migration & Range Maps
Migrates in flocks. Migration parallels the coastline, usually a short distance offshore. Rarely strays inland in fall and winter.
Description
35-40" (89-102 cm). Large and bulky, with relatively short tail, big head, thick bill. Adult has broad white band across throat behind bare yellow face skin; in breeding season, shows white patches on flanks. Immature brownish at first; resembles Double-crested but usually has neck and chest brown, contrasting with white belly. Throat pouch dull yellow, not orange.
Size
About the size of a Heron
Color
Black, Brown, Tan, White
Wing Shape
Broad, Rounded
Tail Shape
Long, Rounded, Wedge-shaped
Songs and Calls
Deep guttural grunts.
Call Pattern
Flat, Simple
Call Type
Raucous
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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Behavior
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.
Feeding Behavior
See family introduction. Most foraging is within 10' of surface, although can dive to 30'.
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.
Conservation
Conservation Status
In recent decades, North American population has increased dramatically, and breeding range has expanded southward along coast.
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.