Olivaceous Cormorant

From Wikipedia, the free encyclopedia

iOlivaceous Cormorant

Scientific classification

Kingdom:	Animalia
Phylum:	Chordata
Class:	Aves
Order:	Pelecaniformes
Family:	Phalacrocoracidae
Genus:	Phalacrocorax
Species:	P. olivaceus

Binomial name

Phalacrocorax olivaceus
(Humboldt, 1905)

The Olivaceous Cormorant or Mexican Cormorant, Phalacrocorax olivaceus is a medium-sized member of the cormorant family found in tropical and near tropical regions of North and Central America, from the south-central United States (chiefly Texas and Louisiana) south to Nicaragua. It can be found both at coasts and inland. It is also found in Cuba and the Bahamas. From Costa Rica southwards it is replaced by the Neotropic Cormorant Phalacrocorax brasilianus, and some authors treat it as a subspecies of that form, classifying it as P. b. mexicanus.

The Olivaceous Cormorant is an all black bird except for a tuft of white feathers above the ear and scattered white filoplumes on the side of the head and the neck, only seen in the breeding season. The lores and gular skin become orange or dark yellow in breeding birds. The upper wings are somewhat greyer than the rest of the body. Adults males weigh from 1.1 to 1.5 Kg, adult females 50 to 100 grams less. Information about their prey is sparse, but inland birds seem to feed on small, abundant fish in ponds and sheltered inlets, less than 10 cm in length, with an individual weight of a gram or two, such as Poecilia spp. especially the sailfin molly Poecilia latipinna. The birds' dives are correspondingly brief, between 5 and 15 seconds.

Olivaceous cormorants nest in small colonies, building stick nests a few metres above ground (or water) in bushes or trees. Most pairs lay 3 eggs, but the mean number hatched is less than 2.