Designed by Paul Smith 2006. This website is copyrighted by law.
Material contained herewith may not be used without the prior written permission of FAUNA Paraguay.
Photographs on this web-site were taken by Paul Smith, Hemme Batjes, Regis Nossent,
Alberto Esquivel, Arne Lesterhuis, José Luis Cartes, Rebecca Zarza and Hugo del Castillo and are used with their permission.
PHALCROCORACIDAE - CORMORANTS
A single, medium-sized species with semi-aquatic habits. Though most cormorants are marine, the species inhabiting Paraguay is more often associated with freshwater habitats. The bill is laterally flattened, hooked at the tip and with the external nostrils completely enclosed - adapted for capturing fish underwater, the fish being gripped in the bill. The legs are short, set well back on the body and the feet are disproportionately large, being used for underwater propulsion. A bare gular pouch can be used for holding fish and in thermoregulation. The tarsi are thick and flattened and the feet are totipalmate - all toes are webbed, including the hallux. The wings are short, rounded and strong, the species flies in strings with steady wing beats and periods of gliding. The tail is short, stiff and wedge-shaped and is used for steering underwater. Cormorants possess two carotid arteries. Modified barbs on the contour feathers allow air to escape and water to enter reducing buoyancy - pebbles may also be ingested to further reduce buoyancy. Upon leaving the water cormorants are often seen "drying" their feathers with wings outstretched, though this behaviour may also have some thermoregulatory effect. Complex moult patterns include a complete moult after breeding and a pre-breeding moult affecting the head, neck and parts of the body. Cormorants are colonial breeders, often associating with other waterbirds.
REFERENCES
Campbell B & Lack E 1985 - A Dictionary of Birds - T & AD Poyser.
Johnsgard PA 1993 - Cormorants, Darters and Pelicans of the World - Smithsonian University Press.
Orta J 1992 - Phalacrocoracidae Handbook of the Birds of the World Volume 1 - Lynx Ediciones.
