Morten Thrane Brunnich, who lived from 1737 to 1827, was the first to describe the Great Northern Loon, Gavia immer.
In North America, the bird is commonly called the Common Loon, and in Eurasia it is called Great Northern Diver.
Other names given to it are Loon, Big Loon, Imber Diver, Hell Diver, Ember Goose, Walloon, Ring-necked loon, Black-billed Loon, Guinea Duck, and Greenhead.
The Great Northern Loon breeds across North America, Iceland, Greenland, and Scotland.
It winters on seacoasts or on large lakes which are in the southern parts of Europe and the United States, and as far south as the northwestern areas of Africa.
Great Northern Loons have an unmistakable call, sounding somewhat like a howling wolf or a cooing dove.
They can live in freshwater or saltwater, and they are excellent divers.
They eat bass, trout, sunfish, perch, pike, herring, sea trout, flounder, and rock fish.
It can be seen calmly swimming along the surface, and then abruptly dive for a fish.
On land, it is rather clumsy.
The birds are colored differently in summer and winter.
In summer, the head and neck are a glossy purplish black with greenish reflections.
A patch of white streaks the lower throat.
There is another white patch on both sides of the neck, and a greenish band towards the base of the neck.
Their upper parts are glossy black with white spots.
The underparts are white and streaked with black.
They iris is red, and its feet are black.
It is a common site to see babies perched atop the back of the Great Northern Loon, as for the first few days they are unable to swim.