Double-crested Cormorant
Double-crested Cormorant
Nannopterum auritum
At a Glance
This dark, long-bodied diving bird floats low in the water with its thin neck and bill raised; perches upright near water with wings half-spread to dry. The Double-crested (which rarely looks noticeably crested in the field) is the most generally distributed cormorant in North America, and the only one likely to be seen inland in most areas.
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, Freshwater Wetlands, Lakes, Ponds, and Rivers, Open Ocean, Saltwater Wetlands
Region
Alaska and The North, California, Eastern Canada, Florida, Great Lakes, Mid Atlantic, New England, Northwest, Plains, Rocky Mountains, Southeast, Southwest, Texas, Western Canada
Behavior
Direct Flight, Formation, Soaring, Swimming
Population
630.000
Range & Identification
Migration & Range Maps
Some in Florida and on Pacific Coast may be permanent resident; most are migratory. Migrates in flocks, often following coastlines or rivers. Most travel probably by day.
Description
30-35 (76-89 cm). Adults are blackish all over with orange bare skin on the face and throat, extending up to lores (in front of eye). (Compare the shape of this throat pouch to that of other 颅cormorants.) In breeding plumage, western birds have white head tufts, lacking on eastern birds. Immatures are brownish, paler on foreneck and chest, often fading to whitish there. In flight, the neck is held with a slight crook or bend just behind the head (most cormorants look straight-necked in flight).
Size
About the size of a Mallard or Herring Gull, About the size of a Heron
Color
Black, Brown, Orange, White
Wing Shape
Broad, Rounded
Tail Shape
Long, Rounded, Wedge-shaped
Songs and Calls
Deep guttural grunts.
Call Pattern
Flat, Simple
Call Type
Croak/Quack, Raucous
Habitat
Coasts, bays, lakes, rivers. Very adaptable, may be found in almost any aquatic habitat, from rocky northern coasts to mangrove swamps to large reservoirs to small inland ponds. Nests in trees near or over water, on sea cliffs, or on ground on islands.
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Behavior
Eggs
3-4, sometimes 1-7. Bluish white, becoming nest-stained. Incubation is by both sexes, 25-33 days, typically 28-30.
Young
both parents feed the nestlings. After 3-4 weeks, young may leave ground nests and wander through colony, but return to nest to be fed. Usually first fly at about 5-6 weeks, probably independent at 9-10 weeks.
Feeding Behavior
Forages mostly by diving from surface and swimming underwater, propelled by feet (may sometimes use wings as well). May forage singly or in groups. May forage in clear or muddy water, at mid to upper levels of water more often than near bottom.
Diet
Fish and other aquatic life. Diet varies with season and place, includes very wide variety of fish, also crabs, shrimp, crayfish, frogs, salamanders, eels; sometimes snakes, mollusks, plant material.
Nesting
Usually first breeds at age of 3 years. Nests in colonies, sometimes mixed with wading birds and others. Male displays to female on water by splashing with wings, swimming in zigzags, diving and bringing up pieces of weeds. At nest site, male displays by crouching and vibrating wings while calling. Nest: Site is near water on cliff ledge, on ground on island, or at any height in tree. Nest (built mostly by female, with materials brought by male) platform of sticks and debris, lined with finer materials.
Conservation
Conservation Status
Population has had ups and downs. Probably long-term decline (because of persecution at nesting colonies) until about 1920s, then gradual increase until 1950s. Numbers dropped again through 1960s, probably owing to effects of persistent pesticides. After DDT was banned in 1972, populations began increasing again, still increasing and expanding range through the present day. In some regions, wildlife management agencies have culled some nesting populations because of concerns that they birds would crowd out other colonial waterbirds.
Climate Threats Facing the Double-crested 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.