The Phalacrocoracidae family of birds is represented by over thirty species of cormorants and shags. All but three are in the genus Phalacrocorax, with the exceptions being the Galapagos Flightless Cormorant, the Kerguelen Shag and the Imperial Shag.
The names “cormorant” and “shag” were originally those of the two species of the family found in Great Britain, Phalacracorax carbo (the Great Cormorant) and P. aristotelis (the Common Shag). “Shag” refers to the bird’s crest.
As other species were discovered by English-speaking sailors and explorers, some were called cormorants and some shags depending on whether they had crests or not. Sometimes the same species is called a cormorant in one part of the world and a shag in another, e.g. the Great Cormorant is called the Black Shag in New Zealand (the birds found in Australasia have a crest that is absent in European members of the species).
Cormorants and shags are medium-to-large seabirds with mainly dark plumage and areas of colored skin on the face. This area can be bright blue, orange, red or yellow. The bill is long, thin, and sharply hooked. Their webbed feet are four-toed which is a distinguishing feature among the Pelecaniformes order.
They are coastal rather than oceanic birds and some have colonized inland waters. They range around the world except for the central Pacific islands.
All cormorants and shags are fish-eaters. They preferred diet consists of small eels, fish, and even water snakes. They dive from the surface, though many species make a characteristic half-jump as they dive, presumably to give themselves a more streamlined entry into the water. They propel themselves with their feet when under water.
After fishing cormorants go ashore to dry their wings because their feathers are not waterproofed, which is unusual for a water bird. This may help them dive quickly, since their feathers do not retain air bubbles.
Cormorants are colonial nesters, using trees, rocky islets, or cliffs. The eggs are a chalky-blue color. There is usually one brood a year. The young are fed through regurgitation.
Humans have historically exploited cormorants’ fishing skills, in China and Japan, where they have been trained by fishermen. Traditional cormorant fishing can be watched in the city of Inuyama, in Aichi Prefecture in Japan. In Guilin, China, cormorant birds are famous for fishing on the shallow Li River.