dcco

Double-crested Cormorant

Phalacrocorax auritus heuretus and P. a. floridana

At a glance

Three subspecies occur in region; two are represented by resident breeding populations, one is endemic

Freshwater lakes and coastal marine habitats

Distribution limited to northern portion of the region

Not common; nesting population distribution sporadic and local (Bahamas, Cuba)

Nesting populations are a conservation priority

Identification:

Intermediate in size between the larger Great Cormorant and the smaller Neotropical Cormorant [74-91 cm (29-36 inches) total length]. Orange-yellow facial skin and throat pouch.

Adults

Sexes alike, males average larger. Head and body including neck, black. Orange facial skin and pouch. Crest absent in non-breeding birds and not particularly apparent in breeding adults. Mean adult life expectancy 6.1 years, known to survive to over 17 years.

Juveniles

Brownish. Neck and upper breast pale have white feathers scaled with brown.

Alternative Common Names

English: Trash goose

French: Cormoran a aigrettes

Spanish: Cormoran Orejudo, Cormoran Bicrestado, Corua de Mar.

Systematics

Five subspecies are recognized. P. a. auritus breeds over most of species range in the US and Canada; winters along Atlantic and Gulf coast and along Central American coast in Caribbean.

P. a. floridana breeds from Southeastern North Carolina and throughout Florida panhandle and northern Bahamas.

P. a. heuretus is an endemic dwarf race that uses the freshwater lakes on San Salvador and probably Cuba. Small numbers of migrants of the two continental subspecies likely occur in northern West Indies during the winter.

Likely locations

Inland freshwater lakes and ponds. Often seen in small groups, and occasionally in small flocks around inlets and marine areas where fish concentrate.

Distribution

This species is the most common and widespread cormorant the western North America. The heart of the breeding range is in central states and provinces, but also with nesting populations on portions of both coasts. Like the other cormorants it also resides in marine habitats in coastal areas, feeding in bays and sounds and near inlets. Only rarely is it seen at sea out of sight of land. Occurs throughout much of North America, with northern freshwater and coastal populations migrating to ice-free coastal marine and estuarine habitats outside the breeding season. Also occurs in the Bahamas and Cuba. Three subspecies in occur our region, two breed here.

P. a. heuretus breeds in an inland lake on San Salvador, but it is also suspected of nesting on Eleuthera and Rum Cay. The Florida subspecies has bred in the Central Bahamas (Long Island), the taxonomic identity of cormorants nesting in Cuba not clear (could be either or both of these races). In Cuba, it breeds in scattered colonies in small cays off northern coast (from Bahia de Cadiz to Cayo Santa Maria), in southern Havana province, and Golfo de Guacanayabo. Bahamian and Cuban breeding populations are year-round residents.

double-crested cormorants

Biology

At sea

Primarily a freshwater species with birds migrating to coastal ice-free habitats in winter. Females may be more migratory than males. Migrant populations begin to leave southern most wintering areas as early as February. Extent of use of coastal habitats by resident cormorants breeding in Bahamas and Cuba unclear. Coastal birds need feeding, loafing, and roosting sites. Feeds by diving from surface. The diet is mostly fish but prey items of cormorants in marine environments and in the West Indies region unstudied.

At the nest

Nest in colonies, nest of large sticks mostly in trees. Most individuals breeding by 4th year. One to seven pale blue eggs. Incubation 25-28 days, fledging period 6-8 weeks. Young independent of parents by 10 weeks (information from various studies of North American populations). No regional published studies.

Current Population

Area	Breeding Pairs	Source
Coastal Canada	27000	Brown and Nettleship 1984
Maine to Virginia	15333-17000	Buckley and Buckley 1984
Southeastern United States	11840	Clapp and Buckley 1984
San Salvador, Eleuthera, Rum Cay	<1000	White and Lee 2001
Cuba	<1000?
Total for Western Atlantic	55000	Kushlan et al. 2002
Total for North America	740000 and increasing	Kushlan et al. 2002

Conservation Status

This is an abundant species in North America and is of no conservation concern. Populations there are expanding. In the Bahamas the endemic dwarf race (P. a. heuretus) is very rare and probably should be considered as threatened. The more widespread Florida race (P. a. floridanus) breeds from the Carolinas south into the Northern Bahamas and Cuba but is not considered to be of conservation concern.

Conservation Needs

Taxonomic identity of populations (breeding and wintering) in Bahamas (other than San Salvador) and Cuba need to be confirmed. Surveys of nesting colonies needed as there is little information regarding sizes of breeding populations. No information available on the biology of migratory or resident cormorants in the region.

Introduced rats on San Salvador threaten endemic cormorant population and other local species of nesting seabirds.

San Salvador is under the threat of expanding tourist development. There is no specific protection for these birds in the region.

Cormorants typically fall off the radar of both seabird biologists and conservationists concerned with protecting endemic species of land birds and their habitats.

Photos

Selected References:

Brown, R. G. B and D. N. Nettleship 1984. The seabirds of northeastern North America: their present status and conservation requirements. Pages 85-100 in J. P. Croxall, P. G. Evans and R. W. Schreiber (eds). Status and Conservation of the World’s Seabirds. ICBP Tech. Publ., No. 2. 778 p.

Buckley, P. A. and F. G. Buckley. 1984. Seabirds of the North and Middle Atlantic coast of the United States: their status and conservation. Pages 101-133 in J. P. Croxall, P. G. Evans and R. W. Schreiber (eds.). Status and Conservation of the World's Seabirds. ICBP Tech. Publ., No. 2. 778 p.

Clapp, R. B. and P. A. Buckley. 1984. Status and conservation of seabirds in the southeastern United States. Pages 135-155 in J. P. Croxall, P. G. Evans and R. W. Schreiber (eds). Status and Conservation of the World's Seabirds. ICBP Tech. Publ., No. 2. 778 p.

Hatch, J. J. and D. V. Weseloh. 1999. Double-crested Cormorant (Phalacrocorax auritus). In The Birds of North America, No. 441 (A. Pool and F. Gill. Ed.). The Birds of North America, Inc., Philadelphia, PA.

Kushlan, J.A. et al. 2002. Waterbird Conservation for the Americas: The North American Waterbird Conservation Plan, Version I. Waterbird Conservation for the Americas, Washington, DC. 78 p.

White, A and D. S. Lee. 2001. Bahamian Seabirds: an international resource. Pages 59-65 in E. Carey, S. D. Buckner, A. C. Alberts, R.D. Hudson, and D. S. Lee. Protected Areas Management Strategy for Bahamian Terrestrial Vertebrates: Iguanas and Seabirds. IUCN/SSC Conservation Breeding Specialists Group, Apple Valley, MN 55124. 74p.

West Indian Breeding Seabird Atlas by Will Mackin and David Lee is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 United States License. Based on work at www.wicbirds.net. Permissions beyond the scope of this license may be available at www.wicbirds.net.

Suggested Citation: Lee, D. S., W. A. Mackin. 2009. Double-crested Cormorant. West Indian Breeding Seabird Atlas <http://www.wicbirds.net/dcco.html>. Last Updated: _____. Date accessed:_________.

Last updated:
May 24, 2009

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