DIVER, a name applied to many birds, but properly re stricted to the family Colymbidae, containing the single genus Colymbus. They are sea-birds, strong swimmers, and feed mainly on fish. Their legs are set far back on the body, so that they cannot walk more than a few steps at a time ; sometimes they progress on land by a series of bounds. They fly well when once on the wing, and usually resort to fresh water for breeding pur poses. The red-throated diver (C. stellatus) has a patch of bay on the throat in summer dress. This is replaced by black in the beautifully striped black-throated diver (C. arcticus). The Pacific loon (Colymbus, or Gavia Pacifica) resembles the black-throated diver.
The largest form is the great northern diver (C. immer) which has a black back, marked with white spots, a black head and neck, and two semi-collars of black and white vertical stripes. These birds inhabit the Arctic seas of both New and Old Worlds. They breed in the Hebrides, Scandinavia, Canada, Iceland and other suitable places in the North. The American form is usually called loon (q.v.) . There is a remarkable mutual courtship, in which the birds may run erect over the surface of the water (see J. S. Huxley, Journ. Linn. Soc., 1923).