Fig. 136.—Young ostriches just from egg; on ostrich farm at Pasadena, California. (Photograph from life.)

The loons, grebes, auks, etc. (Pygopodes).—The loons, grebes, and auks are aquatic birds, living in both ocean and fresh waters. Their feet are webbed or lobed, and their legs set so far back that walking is very difficult and awkward. But all the birds of this order are excellent swimmers and divers. They are distinctively the diving birds. They have short wings and almost no tail. The dab-chick or pied-billed grebe (Podilymbus podiceps) is common in ponds over all the country. Its eggs are laid in a floating nest of pond vegetation and are often covered with decaying plants. The horned grebe (Colymbus auritus) is common west of the Mississippi in lakes and ponds. The loon or great northern diver (Gavia imber), found all over the United States in winter, is the largest of this group, reaching a length (from bill to tip of tail) of three feet. It is black above with many small white spots, and with a patch of white streaks on each side of the neck and on the throat; it is white on breast and belly. The female is duller, being brownish instead of black.

Fig. 137.—Murres, Uria troile californica, on Walrus Island, (Pribilof Group) Behring's Sea. Note the eggs scattered about over the bare rocks. (Photograph from life by the Fur Seal Commission.)

The auks, guillemots, puffins, and murres (fig. [137]) are ocean birds which gather, in the breeding season, in countless numbers on the bleak rocks and inaccessible cliffs of the northern oceans. Each female lays a single egg (in some cases two or at most three) on the bare rock or in a crevice or sort of burrow. These birds mostly fly well, but are especially at home in the water, feeding exclusively on animal substances found there. A famous species is the great auk (Alca impennis), which has become extinct in historical times. The last living specimen was seen in 1844.

The gulls, terns, petrels, and albatrosses (Longipennes).—The Longipennes are water-birds, mostly maritime, with webbed feet and very long and pointed wings. They are all strong flyers, and most of them are beautiful birds. Their prevailing colors are white, slaty or lead-blue, black, and, in the young, mottled brownish. They subsist chiefly on fish, but any animal substance will be eagerly picked up from the water; some of the gulls forage inland. Occasionally great flocks may be seen following a plow near the shore and feeding on the grubs and worms exposed in the freshly-turned soil. Some of the gulls, like the great black-backed gull (Larus marinus), attain a length of two and one-half feet. The terns (Sterna) are mostly smaller than the gulls, have a bill not so heavy and not hooked, and have the tail forked.

The fulmars, shearwaters, petrels, and albatrosses are strictly maritime. The albatrosses are very large, the largest being three feet long with a spread of wing of seven feet. They are often found flying easily over the open ocean at great distances from land. Like the auks and puffins, the fulmars and shearwaters gather in extraordinary numbers on rocky ocean islets or cliffs of the coast to breed.