The Great Cormorant is a large black bird, but there is a wide variation in size in the species wide range. Weight is reported from 1.5 kg (3.3 lbs) to 5.3 kg (11.7 lbs), with a typical range from 2.6 to 3.7 kg (5.7-8.2 lbs). Length can vary from 70 to 102 cm (28–40 in) and wingspan from 121 to 160 cm (48–63 in). It has a longish tail and yellow throat-patch. Adults have white thigh patches in the breeding season. In European waters it can be distinguished from the Common Shag by its larger size, heavier build, thicker bill, lack of a crest and plumage without any green tinge.
This is a very common and widespread bird species. It feeds on the sea, in estuaries, and on freshwater lakes and rivers. Northern birds migrate south and winter along any coast that is well-supplied with fish.
The Great Cormorant breeds mainly on coasts, nesting on cliffs or in trees (which are eventually killed by the droppings), but also increasingly inland. 3-4 eggs are laid in a nest of seaweed or twigs.
The Great Cormorant can dive to considerable depths, but often feeds in shallow water. It frequently brings prey to the surface. A wide variety of fish are taken: cormorants are often noticed eating eels, but this may reflect the considerable time taken to subdue an eel and position it for swallowing, rather than any dominance of eels in the diet. In British waters, dive times of 20–30 seconds are common, with a recovery time on the surface around a third of the dive time.
Cormorant fishing is practiced in China, Japan, and elsewhere around the globe. In it, fishermen tie a line around the throats of cormorants, tight enough to prevent swallowing, and deploy them from small boats. The cormorants catch fish without being able to fully swallow them, and the fishermen are able to retrieve the fish simply by forcing open the cormorants’ mouths, apparently engaging the regurgitation reflex.
In North Norway, cormorants are traditionally seen as semi-sacred. It is regarded as good luck to have cormorants gather near your village or settlement.
(From Wikipedia, 12 May 2011)
Great cormorants are found in shallow, aquatic habitats, such as the coasts of oceans and large lakes and rivers. In North America, great cormorants are strongly associated with marine coastlines, in contrast to their smaller cousins,Phalacrocorax auritus. In Europe, great cormorants are also found in inland, freshwater areas and in coastal estuaries. Nesting habits may vary among subspecies. North American great cormorants (P. c. carbo) nest mainly along coasts. Eurasian subspecies (P. c. sinensis) nest in inland areas, but the two subspecies sometimes occur in nesting colonies together in areas of recent overlap (British Isles). (Hatch et al., 2000)
Habitat Regions: Temperate; Tropical; Saltwater or marine; Freshwater
Aquatic Biomes: Lakes and Ponds; Rivers and Streams; Coastal
Other Habitat Features: Estuarine
(From Animal Diversity Web via EOL, 12 May 2011)