Adults can range from 61 to 100 cm (24 to 39 in) in length with a 122-152 cm (48-60 in) wingspan, slightly smaller than the similar Yellow-billed Loon (or `White-billed Diver`). The weight can vary from 1.6 to 8 kg. On average, a Great Northern Diver is about 81 cm (32 in) long, has a wingspan of 136 cm (54 in), and weighs about 4.1 kg. Breeding adults have a black head, white underparts, and a checkered black-and-white mantle. Non-breeding plumage is brownish, with the chin and foreneck white. The bill is black-blue and held horizontally. The bill colour and angle distinguish this species from the similar Yellow-billed Loon.
Habitat and Distribution
The Great northern divers breed in North America, Greenland, Iceland, and Great Britain. This species winters on sea coasts or on large lakes of south Europe and the United States, and south to northwestern areas of Africa.
This species, like all divers, is a specialist fish-eater, catching its prey underwater, diving as deep as 60 m. Freshwater diets consist of pike, perch, sunfish, trout, and bass; salt-water diets consist of rock fish, flounder, sea trout, and herring.
The female lays 1 to 3 eggs on a hollowed-out mound of dirt and vegetation very close to water. Both parents build the nest, sit on the egg or eggs, and feed the young.
Calls and Songs
Its call has been alternately called `haunting,` `beautiful,` `thrilling,` `mystical`, and `enchanting.`