7. Gavia immer. 31 to 35 inches.
In form, loons resemble large grebes, but their feet are full webbed like those of a duck; they have short, stiff tails and long, heavy, pointed bills. They have no tufts or ruffs in breeding season, but their plumage changes greatly. The common loon is very beautifully and strikingly marked with black and white above, and white below; the head is black, with a crescent across the throat and a ring around the neck. In winter, they are plain gray above and white below.
Loons are fully as expert in diving and swimming as are the grebes. They are usually found in larger, more open bodies of water.
Notes.—A loud, quavering, drawn-out “wah-hoo-o-o.”
Nest.—Sometimes built of sticks, and sometimes simply a hollow in the sand or bank under overhanging bushes, usually on an island. The 2 eggs are brownish with a few black specks (3.50 × 2.25).
Range.—N. A., breeding from northern U. S. northwards; winters from northern U. S. southwards.
BLACK-THROATED LOON
9. Gavia arctica. 28 inches.
This loon lives in the Arctic regions and only rarely is found, in winter, in Northern United States. In summer, it can readily be distinguished from the common loon by the gray crown and hind-neck, as well as by different arrangement of the black and white markings. In winter, they are quite similar to the last species but can be recognized by their smaller size, and can be distinguished from the winter plumaged [Red-throated Loon] by the absence of any white markings on the back. Like the grebes, loons have to run over the surface of the water in order to take flight, and they are practically helpless when on land. Their flight is very rapid, in a straight line, and their neck is carried at full length in front. This species has red eyes, as do all the other loons.