The Swimming Birds are very numerous both in species and individuals, and inhabit all countries. According to some Naturalists these Birds which frequent the sea constitute one-fourteenth part of all the Birds on the globe, and the number of species is said to be nearly ten thousand. They feed on vegetables, insects and Fishes, and build their nests on the sand, in nooks and crannies of the rocks, or on the margin of lakes and rivers. THE BLACK-THROATED DIVER. The Black-throated Diver is small and slender. 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. When swimming, they are in the constant habit of dipping their bill in the water with a graceful motion of the head and neck. “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.” The Black-throated Diver has the beak and throat black; summit of the head ashy grey; the breast and the sides of the neck white, with black spots; the back and rump black; the coverts of the wings with white spots, and all the lower parts pure white. The Bird, though rare in England and France, is very common in the north of Europe. It is found on the lakes of Siberia, of Iceland, in Greenland and Hudson’s Bay, and sometimes in the Orkney Islands. The women of Lapland make bonnets with its skin dressed without removing the feathers; but in Norway it is considered an act of impiety to destroy it, as the different cries which it utters are said to prognosticate fine weather or rain. 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 the greatest girth and of a brownish olive sprinkled with black or dark-brown spots, and are larger at one end than at the other. In the spring the Sea-birds assemble in large flocks. In fact certain localities are chosen year after year, and these are occupied by innumerable flocks at certain seasons, all of which seem to live together in perfect harmony.