Occiput and nape cinereous brown; front of the neck violet-black: bill upwards of three inches in length; the upper- mandible slightly curved.
C. arcticus, Temm. Man. d'Orn. torn. 11. p. 913. Black-throated Diver, Mont. Orn. Diet. Bew. Brit. Birds, vol. 11. p. 181. Selb. Illust. vol. 11. p. 411. pl. 77.
Entire length from twenty-four to twenty-six inches. Temm.
(Adult plumage). Head and nape cinereous brown, passing into black on the forehead; throat and fore part of the neck black, with purple and green reflections; immediately beneath the throat a narrow transverse white band longitudinally streaked with black; on the sides of the neck a broader band extending downwards from the ears, streaked longitudinally with black and white; lower part of the neck, and sides of the breast, streaked in a similar manner: back, rump, and flanks, deep black, without spots; scapulars with twelve or thirteen transverse bars of pure white; wing-coverts black, speckled with white: breast and under parts of the body pure white: quills dusky: tail grayish black; under tail-coverts barred with black: bill dusky; the upper mandible more curved than in the last species; the lower mandible not thickened in the middle, and without the groove: irides brown: feet externally brown; internally whitish; membranes whitish. (Young of the year). Only to be distinguished from those of the last species by their inferior size, and characters of the bill as above pointed out: plumage almost entirely similar: there is generally, however, a dusky band running longitudinally down the sides of the neck, which is not present in the young of C. glacialis. At the age of one year, a few black feathers begin to appear on the throat, as well as on the back, rump, and flanks; there is also a slight indication of the broad band of black and white streaks on the sides of the neck. At the end of the second year, the colour of the forehead begins to deepen; the violet-black extends itself over the throat and fore part of the neck, still however mixed with a few white feathers; the band of longitudinal streaks appears more distinct; and the black and white on the upper parts becomes tolerably well-defined. At the age of three years, the plumage is generally matured. (Egg). Dark olive-brown, thinly spotted with umber-brown: long. diam. two inches nine lines; trans, diam. one inch ten lines.
Inhabits the Arctic Regions, but appears occasionally as a winter visitant on different parts of the British coast, as well as on lakes and rivers inland. Feeds on fish, frogs, insects, and aquatic vegetables. Nest placed amongst reeds and rushes in marshy situations, or on the banks of rivers. Eggs two in number. Obs. The Lesser Imber of Bewick is probably the young of this species.