Sea ravens dive with all four toes webbed together
Roughly forty species of cormorants and shags fill family Phalacrocoracidae, weighing from about a third of a kilogram up to five kilograms with wings often spanning sixty to one hundred centimeters. Hooked bills, mostly dark feathers, and fully webbed feet mark surface-diving fish hunters absent only from central Pacific islands.
About 40 species make up the family Phalacrocoracidae, and in 2021 ornithologists settled on a seven-genus scheme based on a 2014 genetic study. Cormorant probably shortens the Latin for sea raven, and Germanic languages called them sea ravens until after the Middle Ages. Shag first named the crested European shag in Britain, as opposed to the great cormorant, but elsewhere the labels were handed out haphazardly: in New Zealand every species is a shag, including four called cormorants elsewhere.
They range from the pygmy cormorant, as small as 45 cm and 340 g, to the flightless cormorant of the Galápagos at up to a metre and 5 kg; the recently extinct spectacled cormorant averaged 6.3 kg. Northern species are mostly dark, but many southern ones are black and white, and breeding birds flush bright blue, orange, red, or yellow on bare facial skin. All four toes are webbed, and the bill is thin and hooked.
Every species eats fish, diving from the surface, often with a little hop for a cleaner entry, and swimming with the feet. Imperial shags carrying tiny cameras have been filmed at 80 metres. Short wings help underwater but give them some of the highest flight costs of any bird. Afterwards they famously stand with wings spread; a study of great cormorants concluded the pose dries the feathers.
They nest in colonies on cliffs, islets, or trees, lay chalky-blue eggs, usually raise one brood a year, and feed chicks by regurgitation. Found everywhere except the central Pacific islands, they are birds of coasts rather than open ocean.
Source: Cormorant
