Latin Synonyms.—Colymbus arcticus: Linn., Latham, Temminck, Jenyns, Yarrell, Bonaparte.
French Synonyms.—Plongeon Lumme: Temminck. Plongeon Arctique: Cuvier.
Smaller and more slender than the Great Northern Diver, this species retains many of its characteristic habits. It floats deep in the water, and when alarmed swims at surprising speed, with outstretched neck and rapid beat of the wings, and little more than its head above the surface. It flies high and in a direct course with great rapidity. Mr. Selby describes an ineffectual pursuit of a pair on Loch Shin, in Sutherlandshire, which was long persevered in. In this case submersion frequently took place, which continued for nearly two minutes at a time, and they generally reappeared at nearly a quarter of a mile distant from the spot at which they went down. In no instance did he ever see them attempt to escape by taking wing. "I may observe," says this acute ornithologist, "that a visible track from the water to the nest was made by the female, whose progress on land is effected by shuffling along upon her belly, propelled from behind by her legs." When swimming, they are in the constant habit of dipping their bill in the water with a graceful motion of the head and neck.
The eggs, of which there are two, sometimes three in the same nest, are of a very elongated oval form, three inches in length, two inches in their greatest girth, and of a brownish olive sprinkled with black or dark-brown spots, and are larger at one end than at the other.
The Red-throated Diver (Colymbus septentrionalis).
English Synonyms.—Red-throated Loon, Red-throated Diver: Montagu, Selby, Yarrell. Speckled Diver: Montagu.
Latin Synonyms.—C. septentrionalis: Linn., Latham, Jenyns, Bonaparte, Temminck. C. borealis, Siviatus, and stellatus: Latham.
French Synonyms.—Plongeon Col Marin, ou à Gorge Rouge: Temminck.
The Red-throated Diver is smaller than either of the preceding, the plumage is dense and firm, the wings of moderate length, the tail rounded and firm.
From the beginning of October to the middle of May these birds are constantly found on our northern coasts, and on the rivers and estuaries with which they abound. When on a long journey, they keep at a great height, moving rapidly in a direct course with outstretched wings. On these occasions they exceed the speed of most of their congeners. With their long outstretched necks and snow-white breasts, from their comparatively short wings, they present a curious and novel sight. When swimming they are extremely vigilant, and permit nothing to approach them. On the appearance of a boat they glide as it were out of sight under the water, without noise or flutter, and thence pursue their way with great rapidity, using wings as well as feet to propel themselves.