Great Northern Diver and White Billed Diver

Gavia immer, the great northern diver (Europe), also known as common loon (North America), Tuullik (Greenlandic), Himbrimi (Icelandic), Islom (Norwegian), and Gavia adamsii, the white-billed diver (Europe), also known as yellow-billed loon (North America), are both large birds (3—6 kg in weight) and have heavy stout bills; that of the great northern is straight and black, and that of the white-billed diver is cream colored and appears up-tilted. Both have glossy black hoods interrupted by windows of white stripes on the chin and nape. The back is black, heavily striped with striking black and white patterning. Inuit legend has it that the raven made such fun of these patterns on the back that the loons always face their aggressors when performing the "penguin dance" threat display, in order to hide the foolish patterning on their backs. In winter, both species lose

Black-throated Arctic loon (Gavia arctica). Copyright Curtis Carley, courtesy US Fish and Wildlife Service

their spectacular garb and become grayish-brown above, with dark crown and nape, and pale, almost white below. The great northern diver breeds mainly in North America between 40° N and 78° N, but extends to Greenland, Iceland, and Bear Island. Nesting is usually associated with very large deep freshwater lakes, in areas of coniferous forest but also into open tundra; the nests are invariably on islets, less commonly along shores. Great northern divers winter along coasts of the North Atlantic and northeastern Pacific, frequently associated with exposed, hard rock shores and sheltered bays. The white-billed diver replaces the smaller species in the Russian Arctic, breeding along Arctic Ocean coasts as far north as 78° N, generally well north of the treeline, and extends into Alaska and the western Canadian Arctic. This species winters in coastal waters of the northwest and northeastern Pacific and off Norway in the Old World. Both species tend to nest as soon as habitats are freed from the spring thaw, creating a modest nest from vegetation adjacent to the water's edge. Little is known about the breeding biology of white-billed divers, but great northern sivers tend to lay two eggs, which after 3-4 weeks of incubation hatch dark brown chicks that fledge at 70-77 days. Birds are thought to reach sexual maturity at 2 years of age, but there are few records from ringing recoveries to support the idea that these birds probably live for 20 or more years. Both species are masters of the underwater pursuit of fish, most usually in 4-10 m of water where they can be submerged for up to a minute, often resurfacing far from the diving point. Because of their mournful song, great northern and white-billed divers were thought to act as a guide into the netherworld; hence, early Inuit cultures buried Loon skulls in graves. Animal dances among the western Inuit of North America featured many ceremonial bird masks, and the striking yellow dagger bill of Gavia adamsii figured prominently in the "Dance of the Loon." The drum dance clothing of the Copper Inuit of Coronation Gulf, Northwest Territories also featured the head and bill in ceremonies that welcomed the arrival of travelers and friends or celebrated a successful hunt. More functionally, the large diver skins were used in the coats of Western Alaskan Inuit, and their use as storage bags by the Bering Strait Inuit continues today in Gjoa Haven, Nunavit, where, "loonie bags" are still used to hold and keep dry the precious dried moss, bog cotton, and flints required to start fires.

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