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Phalacrocorax auritus - Double Crested Cormorant

Double Crested Cormorant image

Geographic range:

Southern Alaska to Sinaloa, Mexico

Key features:

It has a large, rounded throat pouch that is yellow-orange year-round. The breeding adult has a tuft curving back on either side of its head from behind the eyes that can be hard to see. The tufts are largely white in western birds, but black and less obvious is eastern birds.

Similar species:

Phalacrocorax penicillatus -- Brandt's Cormorant
Phalacrocorax pelagicus -- Pelagic Cormorant

Habitat(s):

bay (rocky shore), estuary, exposed rocky shore, kelp forest, protected rocky shore
 

Primary common name:

Double Crested Cormorant

General grouping:

Seabirds and shorebirds

ITIS code:

174717
 

Geographic Range

Range Description:

Phalacrocorax auritus is widely distributed across North America. They can be found as far north as southern Alaska and as far south as Sinaloa, Mexico as well as in Belize, the Bahamas and Cuba. This cormorant can be found on marine and inland waters throughout their range including along the Great Lakes and the St. Lawrence Seaway.

Habitats

bay (rocky shore), estuary, exposed rocky shore, kelp forest, protected rocky shore

Habitat notes:

Phalacrocorax auritus is found in a variety of marine and inland aquatic habitats, such as ponds, lakes, rivers, lagoons, estuaries, and open coastline. They can also be found perching on rocks, sandbars, pilings, trees or docks. Breeding territories are typically located on small rocky or sandy islands, trees, or ocean cliffs.

Abundance

Relative abundance:

Phalacrocorax auritus is common and widespread.

Species Description

General description:

Phalacrocorax auritus is the most numerous and widespread cormorant in North America and is growing in numbers throughout its range. It is the only cormorant that occurs in large numbers inland as well as on the coast. It is a member of the Cormorant Family Phalacrocoracidae in the Order Pelecaniformes in the Class Aves. There are several subspecies of double-crested cormorants that are differentiated by size and the color and shape of their crests. The subspecies include the Florida Cormorant, Phalacrocorax auritus floridanus, found around Florida, North Carolina, and the Gulf Coast; the White-Crested Cormorant, Phalacrocorax auritus cincinatus, found in Alaska; and the Farallon Cormorant, Phalacrocorax auritus albociliatus, found on the coasts and inland lakes of the Pacific slope.

Distinctive features:

Phalacrocorax auritus is a large cormorant with a long dark body and long neck. The plumage is green though it appears black and the back and wings are brownish. It also has a large, rounded throat pouch that is yellow-orange year-round. The breeding adult has a tuft curving back on either side of its head from behind the eyes that can be hard to see. The tufts are largely white in western birds, but black and less obvious is eastern birds. The breeding adult also has blue eyelids, a dusky bill and orange on the throat sac and lores. In all birds, the bill is narrow and hooked and the eyes are turquoise. The legs are short and dark and the feet are webbed and black. Immature birds are brown above and variably pale below with a white chest and foreneck. Another distinguishing feature of Phalacrocorax auritus is that it spreads its wings to dry while resting and swims with its bill angled upward. Flocks can also be seen flying in V formation with their necks kinked.

The Immature birds sometimes have a pouch that is edged with white which makes it resemble the Neotropic Cormorant, Phalacrocorax brasilianus. However, Phalacrocorax brasilianus is slimmer with a longer tail, and the facial skin is smaller and pointed at the rear. Phalacrocorax auritus can be differentiated from Brandt’s, Phalacrocorax penicillatus, and Pelagic Cormorants, Phalacrocorax pelagicus, by its distinctively kinked neck in flight and its longer and more pointed wings. Also, Phalacrocorax penicillatus has less conspicuous and dark facial skin that is bordered with pale feathers and Phalacrocorax pelagicus is smaller and slimmer with a much smaller bill and red facial skin. The Great Cormorant, Phalacrocorax carbo, can also be confused with Phalacrocorax auritus, but can be differentiated by Phalacrocorax carbo’s bigger size and yellow facial skin bordered by white feathers.

Size:

Phalacrocorax auritus can grow to a length of 90 cm with a wingspan of 132 cm and a weight of 2500 g.

Natural History

General natural history:

Phalacrocorax auritus is a gregarious bird and can be found in small and large groups during breeding and in the winter. The often feed in large flocks, gather in nocturnal roosts and migrate in large groups. Their voice is usually silent, but they may croak at their nests. Phalacrocorax auritus may live until about 17 years of age, but on average lives to only 6 years of age.

While Phalacrocorax auritus populations have been increasing, in the past they have suffered dramatic declines both for being persecuted as predators of commercial fish in the wild and at hatcheries as well as due to the use of contaminants, such as DDT. El Nino events have also played a role in reducing the number of breeding pairs as well as the reproductive success of breeders. They have also been significantly killed or injured from oil spills, when caught in fishing gear and from disturbance to nesting sites. Since the 1970s, likely due to the ban of DDT and other contaminants, populations have increased dramatically. However, now that populations are so large, these birds are again being blamed for declines in sport fisheries and for devastating fish farms.

Predator(s):

Phalacrocorax auritus’s eggs and chicks are preyed on by Gulls, Larus sp., crows, jays, and grackles, Quiscalus sp.. Chicks are also preyed on by Coyotes, Canis latrans, foxes, Vulpes sp., and Raccoons, Procyon lotor. Adults and chicks are susceptible to predation by Bald Eagles, Haliaeetus leucocephalus.

Prey:

Phalacrocorax auritus feeds primarily on fish, but also eats insects, crustaceans and amphibians.

Feeding behavior

Carnivore

Feeding behavior notes:

Phalacrocorax auritus is an opportunistic feeder that may take a variety of prey depending on availability. They generally hunt in shallow water, less than 8 m deep, and within 5 km of the shore. They feed during the day and when pursuing schools of fish they may feed together in flocks. These birds dive for fish from the water’s surface pursuing prey underwater propelling themselves by their powerful, webbed feet and grabbing fish in their hooked bill.

October - March

Migration:

Phalacrocorax auritus is usually a permanent resident on the coasts. However in inland areas some migrants move to the coast. Most migrants depart in October and return in March.

April - August

Reproduction:

Phalacrocorax auritus breeds once a year between April and August with peak activity in May through July. These monogamous birds begin becoming sexually reproductive at two years of age and nest in colonies of up to three thousand pairs. The male chooses a nest site and then tries to win a female by performing elaborate courtship dances and wing waving displays that show off the brightly colored skin on his head and neck. As part of courtship, the male may even bring nest material to the female. They both get to work building a nest, though the female does most of the work building. The nesting site may be on a rocky cliff near water, on the ground, on an island or in a tree. The nest is constructed out of sticks, vegetation, and even debris found nearby, such as fishnet or rope. Upon forming a pair, Phalacrocorax auritus looses its crest.

After the nest is complete, the female lays one to seven, though usually four, pale bluish white eggs. The eggs are laid one to three days apart and both parents incubate the eggs. The eggs hatch after 25 to 28 days and the young are considered altricial, meaning that they are helpless and dependent on their parents for food. Both parents feed the young regurgitated food two to six times a day and on hot days will even fetch water and pour it into their chicks� mouths. The chicks begin to leave the nest after about 3 to 4 weeks, can fly and dive at about 6 weeks. During this time, the chicks may roam the colony, but return to the nest site to be fed and do not become independent until about 10 weeks of age. Second broods are rare in this species.
Click on an image below to view a larger version in the SIMoN Photo Library. You will also be able to view important information on each photo such as photographer, date, caption and more.
Alden, P., F. Heath, R. Keen, A. Leventer, and W. Zomlefer. 2002. National Audubon Society Field Guide to California. A.A. Knopf, New York, NY.
Dunn, J.L. 1999. Birds of North America. National Geographic, Washington, D.C. 464 p.
Kirschbaum, K. and R. Rodriguez. 2002. Gavia immer, Animal Diversity Web. World Wide Web electronic publication. http://animaldiversity.ummz.umich.edu, Accessed [08/05/06].
WWW
Cornell Lab of Ornithology
All About Birds
http://www.allaboutbirds.org/guide/search

WWW
Seattle Audubon Society.
http://www.seattleaudubon.org/birdweb/