The great northern diver or common loon is a large member of the family, Gaviidae.

Great Northern Diver

The great northern diver or common loon is a large member of the family, Gaviidae.

The Great Northern Diver, known in North America as the Common Loon (Gavia immer), is a large member of the loon, or diver, family. Adults can range from 61-100 cm (24-40 inches) in length with a 122-152 cm (4-5-foot) wingspan, slightly smaller than the similar White-billed Diver or "Yellow-billed Loon". The weight can vary from 1.6 to 8 kg (3.6 to 17.6 lbs). On average a Common Loon is about 81 cm (32 inches) long, has a wingspan of 136 cm (54 inches), and weighs about 4.1 kg (9 lbs).

Great Northern Diver

The Great Northern Diver, known in North America as the Common Loon (Gavia immer), is a large member…

"Colymbus torquatus. Common Loon. Great Northern Diver. Adult: Bill black, the tip and cutting edges sometimes yellowish. Feet black. Iris red. Head and neck deep glossy greenish-black, with lustrous purplish reflections on the front and sides of the head. A patch of sharp white streaks on the throat, and another larger triangular patch of the same on each side of the neck lower down, the two last nearly or quite meeting behind, separate in front. Sides of breast striped with black and white. Entire upper parts, wing-coverts, inner secondaries, and sides under the wings, glossy black; all except the sides thickly marked with white spots; those of the scapulars, tertials, and middle back, large, square, and regular; those of other parts smaller, oval, smallest on rump, most numerous on wing-coverts. Upper tail-coverts greenish-black, immaculate. Wing-quills brownish-black, lighter on inner webs. Under surface of wings, axillars, and under parts generally from the neck, pure white; the lower belly with a dusky band. The white throat-patch consists usually of five or six streaks; in this, as in the lateral neck-stripes, the individual feathers are broadly black, with sharp white edges toward their ends." Elliot Coues, 1884

Common Loon

"Colymbus torquatus. Common Loon. Great Northern Diver. Adult: Bill black, the tip and cutting edges…

"Colymbus torquatus. Common Loon. Great Northern Diver. Adult: Bill black, the tip and cutting edges sometimes yellowish. Feet black. Iris red. Head and neck deep glossy greenish-black, with lustrous purplish reflections on the front and sides of the head. A patch of sharp white streaks on the throat, and another larger triangular patch of the same on each side of the neck lower down, the two last nearly or quite meeting behind, separate in front. Sides of breast striped with black and white. Entire upper parts, wing-coverts, inner secondaries, and sides under the wings, glossy black; all except the sides thickly marked with white spots; those of the scapulars, tertials, and middle back, large, square, and regular; those of other parts smaller, oval, smallest on rump, most numerous on wing-coverts. Upper tail-coverts greenish-black, immaculate. Wing-quills brownish-black, lighter on inner webs. Under surface of wings, axillars, and under parts generally from the neck, pure white; the lower belly with a dusky band. The white throat-patch consists usually of five or six streaks; in this, as in the lateral neck-stripes, the individual feathers are broadly black, with sharp white edges toward their ends." Elliot Coues, 1884

Loons

"Colymbus torquatus. Common Loon. Great Northern Diver. Adult: Bill black, the tip and cutting edges…