Quantcast

Great Northern Loon, Gavia immer

A large member of the loon, or diver, family of birds, this species is well-known as the Common Loon in North America and the Great Northern Diver in Eurasia; its current name is a compromise proposed by the International Ornithological Committee.

There are 5 loon species that make up the genus Gavia, the only genus of the family Gavidae and order Gaviiformes. The Great Northern Loon is only one of those 5 species. The Yellow Billed Loon or the While Billed Diver is a large black headed species and is it’s only relative. The genus name Gavia was the Latin expression for smew. It is a small sea-duck and is quite dissimilar to loons and just so happens to be another black and white seabird which swims and dives for fish. It is unlikely that the Ancient Romans knew much about loons, as these are limited to more northern latitudes and since the end of the last glacial period seems to have occurred only as exceptional winter migrants in the Mediterranean area. The distinct name immer is derived from North Germanic names for the bird such as modern Icelandic “Himbrimi”. The name is interconnected to Swedish immer and emmer, meaning the grey or blackened ashes of a fire, indicating the dark color of its feathers; or to Latin immergo, to immerse, and immersus, submerged.

The name “diver” is a European name and it comes from the bird’s habit of catching fish by calmly swimming along the top of the water and then rapidly plunging into the water. The name “loon” is North American and is a reference to the bird’s clumsiness on land, and is derived from Scandinavian words for lame.

The mature adults can range from 24-40 inches in length with a 4-5 foot wingspan, which is a little smaller than the Yellow-Billed Loon. They weight can vary from 3.6 to 17.6 lbs. A Great Northern Loon, on average, is about 32 inches long, and has a wingspan of 54 inches and weighs about 9lbs. Breeding adults have white underparts, a checkered black and white mantle, and a black head. Non breeding colors of the plumage are usually brownish, with a white chin and foreneck. The bill is held horizontally and is usually black-blue. The color and the angle of the bill make a distinction between from the similar Yellow Billed Loon.

This bird breeds in North America, Greenland, Iceland, and Scotland. It winters on sea coasts or on the large lakes of south Europe or the United States and in south to northwestern areas of Africa. This species, like all divers, is a professional fish-eater, catching its prey underwater, even diving as deep as 200 ft. Freshwater diets can be composed of perch, pike, sunfish, trout, and bass; saltwater diets are made up of rock fish, flounder, seat trout, and herring. For take off, the bird needs a long distance, and is graceless on landing. Its clumsiness on landing is due to its legs being located at the back of its body; this is ideal for diving, but not so much for walking. When the birds land on water, they slide along their bellies to slow down, rather than on their feet because they are so far back. The loon swims gracefully on the surface of the water, it dives as well as any other flying bird, and flies competently for hundreds of kilometers during migration. It flies with the neck outstretched, normally calling a specific tremolo that can be used to identify a flying loon. Its call has been called “haunting”, “beautiful”, “thrilling’, “mystical”, and “enchanting”.

Their nests are generally placed on islands; where predators on the ground cannot normally get to them. However, nestlings and eggs have been taken by gulls, corvids, raccoons, skunks, minks, foxes, snapping turtles, and large fish. Adults aren’t usually preyed upon, but have been taken by sea otters when wintering and Bald Eagles. Ospreys have been recorded harassing divers, more likely out of kleptoparasitism than predation. When approached by a predator of either itself or its nest, divers will sometimes attack the predator by running at it and trying to impale it through its abdomen or the back of its head or neck.

The female loon lays 1 to 3 eggs on a hollowed-out mound of dirt and vegetation very close to the water. Both parents will build the nest, sit on the egg or eggs, and feed the young.

These birds have vanished from some lakes in eastern North America because of the effects of acid rain and pollution, as well as lead poisoning from fishing sinkers and contamination from mercury from industrial waste. Artificial floating nesting platforms have been provided for the loons in some lakes to lessen the impact of changing water levels due to dams and other human activities. The Great Northern Loon is one of the species to which the Agreement on the Conservation of African-Eurasian Migratory Waterbirds applies.

This diver is well known in Canada, existing on the “loonie” coin and the former series of $20 bill, and is the provincial bird of Ontario. It is also the state bird of Minnesota.

The voice and appearance of the Great Northern Loon has made it well-known in more than a couple Native American tales. This includes a story of a loon which created the world in a Chippewa story; a Micmac saga describes Kwee-Moo, the loon who was a special messenger of Glooscap (Glu-skap), the tribal hero; native tribes of British Columbia believed that a surplus of calls from this bird foresaw rain, and even brought it; and the tale of the loon’s necklace was handed down in many editions amongst the Pacific Coast peoples. The folk names include big loon, black billed loon, call-up-a-storm, ember-goose, greenhead, guinea duck, imber diver, ring-necked loon, and Walloon.

The loon is the central plot of the novel Great Northern written by Arthur Ransome. It is known as throughout as Great Northern Diver, with the outdated scientific name Colymbus immer. The story’s setting is in the Outer Hebrides, where the main characters-a group of children on holiday-notice a couple of loons obviously nesting there. When they checked their bird book, they found these birds to be the Great Northern Loon; however, this has not been seen beforehand to nest in Northern Scotland, so they asked for help from an ornithologist. He confirmed that these birds were in fact the Great Northern; unfortunately, it soon becomes apparent that he doesn’t not wish to merely watch, but wants to steal the eggs to add them to his collection; but to do this, he must first kill the birds. Published in 1947, this book was one where the conservationists are the eventual winners over the egg collector, at a time when egg collecting was not seen to be harmful.

Image Caption: A Great Northern Loon (also known as the Great Northern Diver and the Common Loon) in Minocqua, Wisconsin, USA. Credit: John Picken/Wikipedia  (CC BY 2.0)

Great Northern Loon Gavia immer


comments powered by Disqus