cormorants
The bird family Phalacrocoracidae is represented by some 40 species of cormorants and shags. Several different classifications of the family have been proposed recently, and the number of genera is disputed.
About the name of cormorant: There is no consistent distinction between cormorants and shags. The names "cormorant" and "shag" were originally the common names of the two species of the family found in Great Britain, Phalacrocorax carbo (now referred to by ornithologists as the Great Cormorant) and P. aristotelis (the Common Shag). "Shag" refers to the bird's crest, which the British forms of the Great Cormorant lack. As other species were discovered by English-speaking sailors and explorers elsewhere in the world, 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). Van Tets (1976) proposed to divide the family into two genera and attach the name "Cormorant" to one and "Shag" to the other, but this flies in the face of common usage and has not been widely adopted.
The scientific genus name for cormorant is latinized Ancient Greek, from φαλακρός (phalakros, "bald") and κόραξ (korax, "raven"). This is often thought to refer to the creamy white patch on the cheeks of adult Great Cormorants, or the ornamental white head plumes prominent in Mediterranean birds of this species, but is certainly not a unifying characteristic of cormorants. "Cormorant" is a contraction derived from Latin corvus marinus, "sea raven". Indeed, "sea raven" or analogous terms were the usual terms for cormorants in Germanic languages until after the Middle Ages, and the erroneous belief that these birds were related to ravens lasted at least to the 16th century:
The African Darter (Anhinga rufa), sometimes called the Snakebird, is a water bird of tropical sub-Saharan Africa.
This species builds a stick nest in a tree and lays 3-6 eggs. It often nests with herons, egrets and cormorants.
It is an 80 cm long cormorant-like fish-eating species with a very long neck which occurs in both saline and fresh water, especially near mangroves. It often swims with only the neck above water.
The male is mainly glossy black with white streaking, but females and immature birds are browner. The African Darter differs in appearance from the American Darter most recognisably by its thin white lateral neck stripe against a rufous background colour.
Cormorants and shags are medium-to-large seabirds. They range in size from the Pygmy Cormorant (Phalacrocorax pygmaeus), at as little as 45 cm (18 in) and 340 g (12 oz), to the Flightless Cormorant (Phalacrocorax harrisi), at a maximum size 100 cm (40 in) and 5 kg (11 lb). The recently-extinct Spectacled Cormorant (Phalacrocorax perspicillatus) was rather larger, at an average size of 6.3 kg (14 lb). The majority, including nearly all Northern Hemisphere species, have mainly dark plumage, but some Southern Hemisphere species are black and white, and a few (e.g. the Spotted Shag of New Zealand) are quite colourful. Many species have areas of coloured skin on the face (the lores and the gular skin) which can be bright blue, orange, red or yellow, typically becoming more brightly coloured in the breeding season. The bill is long, thin, and sharply hooked. Their feet have webbing between all four toes, as in their relatives.
The cormorants are coastal rather than oceanic birds, and some have colonised inland waters - indeed, the original ancestor of cormorants seems to have been a fresh-water bird, judging from the habitat of the most ancient lineage. They range around the world, except for the central Pacific islands.
Cormorants are colonial nesters, using trees, rocky islets, or cliffs. The eggs are a chalky-blue colour. There is usually one brood a year. The young are fed through regurgitation. They typically have deep, ungainly bills, showing a greater resemblance to those of the pelicans', to which they are related, than is obvious in the adults.
The cormorants are a group traditionally placed within the Pelecaniformes or, in the Sibley-Ahlquist taxonomy, the expanded Ciconiiformes. This latter group is certainly not a natural one, and even after the tropicbirds have been recognized as quite distinct, the remaining Pelecaniformes seem not to be entirely monophyletic. Their relationships and delimitation - apart from being part of a "higher waterfowl" clade which is similar but not identical to Sibley and Ahlquist's "pan-Ciconiiformes" - remain mostly unresolved.
Cormorants seem to be a very ancient group, with similar ancestors reaching all the way back to the time of the dinosaurs. In fact, the very earliest known modern bird, Gansus yumenensis, had essentially the same structure, although it was not a cormorant per se. The details of the evolution of the cormorant are mostly unknown, today. Even the technique of using the distribution and relationships of a species to figure out where it came from, biogeography, usually very informative, does not give very specific data for this probably rather ancient and widespread group. However, the closest living relatives of the cormorants and shags are the other families of the suborder Sulae - darters and gannets and boobies -, which have a primarily Gondwanan distribution. Hence, at least the modern diveristy of Sulae probably originated on the southern hemisphere.
After fishing, cormorants go ashore, and are frequently seen holding their wings out in the sun; it is assumed that this is to dry them. Unusually for a water bird, their feathers are not waterproofed. This may help them dive quickly, since their feathers do not retain air bubbles.
Humans have historically exploited cormorants' fishing skills, in China, Japan, and Macedonia, where they have been trained by fishermen. A snare is tied near the base of the bird's throat, which allows the bird only to swallow small fish. When the bird captures and tries to swallow a large fish, the fish is caught in the bird's throat. When the bird returns to the fisherman's raft, the fisherman helps the bird to remove the fish from its throat. The method is not as common today, since more efficient methods of catching fish have been developed.