The Great Cormorant (Phalacrocorax carbo), known as the Great Black Cormorant across the Northern Hemisphere, the Black Cormorant in Australia, the Large Cormorant in India and the Black Shag further south in New Zealand, is a widespread member of the cormorant family of seabirds. It breeds in much of the Old World and the Atlantic coast of North America.
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. In eastern North America, it is similarly larger and bulkier than Double-crested Cormorant, and the latter species has more yellow on the throat and bill. Great Cormorants are mostly silent, but they make various guttural noises at their breeding colonies.