Gavia immer

Descriptioncommon loon are seen on a whale watching boat tour with Eagle Wing Tours in Victoria, British Columbia, Canada on Vancouver Island.

Measure 28–36 inches (71–91 cm). A large, heavy-bodied loon with a thick, pointed, usually black or dark gray bill held horizontally. In breeding plumage, head and neck black with white bands on neck; back black with white spots. In winter, crown, hind neck, and upper parts dark greyish; throat and underparts white.

Habitat

Nests on forested lakes and rivers; winters mainly on coastal bays and ocean.

Nesting

Two olive-brown or greenish, lightly spotted eggs in a bulky mass of vegetation near water’s edge, usually on an island.

Range

Breeds from Aleutian Islands, Alaska, and northern Canada south to California, Montana, and Massachusetts. Winters along Great Lakes, Gulf Coast, and Atlantic and Pacific coasts. Also breeds in Greenland and Iceland.

Voice

Best known call is a loud, wailing laugh, also a mournful yodelled oo-AH-ho with middle note higher, and a loud ringing kee-a-ree, kee-a-ree with middle note lower. Often calls at night and sometimes on migration.

Discussion

John Muir describes its call as “one of the wildest and most striking of all the wilderness sounds, a strange, sad, mournful, unearthly cry, half laughing, half wailing.” As expert divers, loons have eyes that can focus both in air and under water and nearly solid bones that make them heavier than many other birds; they are able to concentrate oxygen in their leg muscles to sustain them during the strenuous paddling that can take them as far as 200 feet (60 m) below the surface. Their principal food is fish, but they also eat shellfish, frogs, and aquatic insects. In recent decades, acid rain has sterilized many lakes where these birds formerly bred, and their numbers are declining. Few people are unmoved by the haunting calls of the loon, one of the best-known and most loved symbols of the northern woods. The common loon is found in every corner of British Columbia, and is synonymous with the wilderness and outdoor adventure.

The breeding distribution of the common loon is spread throughout the province, wherever there are freshwater lakes for nesting and feeding. Loons are well-known victims of acid rain poisoning in eastern lakes, but this has not been so serious a problem in this province. Pressures from human development, however, have pushed them out of some of their historical breeding areas in the south. The common loon is a big, heavy bird. It is adapted to a life in the water, with its webbed feet placed well back on its body, for efficient propulsion and streamlining. But this very adaptation makes the bird extremely vulnerable on land, because it cannot lift its body to walk normally. Not surprisingly, almost all loon nests are located within about one meter of the water’s edge. Most consist of mounds of aquatic vegetation. When the two young are hatched, they soon make for the water, where they are watched closely by the adults. Sometimes, they will seek cover on an adult’s back, or under a wing; a baby loon is a welcome meal for a large fish. The adults feed the young small fish and other aquatic prey. The young begin attempting to fish for themselves, too, but are sometimes stymied by the buoyancy of their downy bodies.

Loons feed by looking below the surface for prey, and then diving to pursue it. Their diet is mainly fish, most of which are smaller than 6 inches (15 cm). When autumn sets in, the loons move south to winter where there is open water; takeoff for loons is a laborious manoeuvre, and they cannot take off from land, or ice-covered lakes. Many loons spend the winter on the coast, where there are fewer breeding birds, abandoning the white-spangled summer plumage for dull winter plumage. On a heaving, grey November sea, they look very different, but still quite at home. Also different, though, is their silence. Through the long months of a West Coast winter, nary a call will be heard. But as the days lengthen, the plumage of the loons begins to brighten, and from within comes the first stirrings of those amazing calls. Before long, they will be gone and will head back to the lakes to raise another generation of loons.