The 10,000 or more different kinds of birds now living in the world are classified in fifteen orders, of which the lowest in rank is that of the ostriches, and allied ratite birds, mostly extinct, that stand in a place apart by reason of their archaic structure and inability to fly. The ostrich is still wild in the arid districts of Africa, Arabia, and Mesopotamia; the rhea is Patagonian; the emus and cassowaries belong to Australia and New Guinea; the apteryx, or kiwi, still survives in New Zealand; and several gigantic ratite birds have recently become extinct in New Zealand and in Madagascar, where egg shells, laid by the prehistoric æpyornis, that will hold two gallons are still found. Some species of these birds were seven feet in height.
[CHAPTER XXIII]
SOME NOTABLE WATER BIRDS
From these relics of geologic antiquity the remainder of the birds now living, and their fossil ancestors as well, differ fundamentally, and are united in a division whose badge is the keel on the sternum; hence they are termed "carinate" birds (Carinatæ). The list begins with the most archaic order, that of the loons, of which three or four species are named, but they are hardly separable. They are as big as geese, have black backs checkered with white spots, white undersurfaces and heads purplish black, variously marked; and these heads and necks have a very reptilian look, as they stretch forward their heads inquiringly, or utter the "wild laughter" that seems so consonant with the lonely waters they frequent. The reptilian suggestion is even stronger in their cousins the grebes, known to gunners as "die-dappers," "hell-divers," etc., on account of the quickness with which they will disappear when alarmed. The family badge is on the feet, where the toes are not connected by a full web, as in loons, but every toe is margined by a flange of firm skin with a scalloped margin. Grebes have a way of swimming with the whole body under water, when the exposed head and neck look very "snaky." The brown and white plumage of grebes is exceedingly close and dense, and their indifference to wet and cold is shown by the fact that their nests are mere rafts of sodden weeds often so loosely tied to the rushes that they go adrift. Grebes abound on all northern waters and are rarely shot since the taking of their silvery breasts for hat ornaments has been stopped.
The penguins constitute an order limited in range to the antarctic region. Their picture is in everybody's mind—a bird that stands as erect as a soldier on two almost invisible legs and a short stiff tail, and carries a small head, sometimes plumed, with a strong pointed bill. The picture usually represents the great flocks that resort in the brief summer to their rocky breeding places on icy shores, each female guarding and incubating her two eggs in the rudest of nests on the ground. These antarctic "rookeries" sometimes hold tens of thousands. During the rest of the year the penguins are at sea, or under it, behaving more like seals than birds, for their scalelike plumage is impervious to water, and their stubby wings are in effect flippers by which they swim under water, the strong-webbed feet acting only as rudders until they come to the surface and can paddle. Penguins feed on crustaceans and mollusks mostly, but also on fish and sea weed.
Next comes that group of wide sea wanderers, the albatrosses and petrels, united in the family Procellariidæ, whose special mark is found in the two bony tubes along the top of the beak that contain the nostrils. Of the albatrosses many species are known, nearly all inhabitants of the southern oceans, although two or three of the largest regularly visit the North Pacific coast, and more rarely one strays into the North Atlantic; certain small species frequent the western coast of South America. The one best known is the "wandering" albatross, whose wings spread nine or ten feet, yet are only nine inches wide. They spend their whole lives on the open ocean, and undoubtedly sleep there, regardless of storm or calm; but in summer land on some lone antarctic island or lofty shore, and construct a heap of mud and rubbish on top of which they deposit two chalky eggs.
Their relatives, the oceanic petrels, are much smaller as a rule, and some no bigger than sparrows. They are of many kinds, including fulmars, shearwaters, etc., and nearly all are black or sooty brown, usually with touches of white. Most of the group are denizens of the southern hemisphere, but some belong to the north and are migratory; and the eastern Atlantic and Mediterranean are the home of the original stormy petrels, which sailors call "Mother Carey's chickens" and regard with mingled superstition and affection; Leach's white-rumped petrel, of our New England coast, shares this name. Some of the far-southern species are almost as big as albatrosses. Petrels get their food from both the waves and the shore and follow ships on long voyages in hope of scraps of flesh thrown overboard. Most of them breed in holes dug in the topsoil of sea-fronting cliffs, and lay white eggs; many hide in these holes by day, and go out only at night, filling the air with wild cries while they hunt; but fulmars and shearwaters, which make rude nests on rough shores or on cliff ledges, often in vast colonies, go abroad in daylight, and throng on the Grand Banks and wherever else fishing is going on.
Next, in the classification based on structure rather than on superficial resemblances, comes a large assemblage of water birds, some exclusively marine, others of inland waters. Here are placed those long-winged, graceful, oceanic flyers, the tropic birds, and the many kinds of gannets, snowy white, that soar and plunge like falcons as they sweep over the waves and pick up incautious squids, fishes, etc. Most of them are tropical, but one gannet is well known on both shores of the North Atlantic where it nests in thousands on the cliff faces that bound such lofty islets as the Bass Rock near Edinburgh, the Hebrides, and Bird Rock in the Gulf of St. Lawrence. The flight is easy and powerful, and the food is caught by a hawklike plunge.