We are ready, then, to concede to the birds as natural rights what we long ago declared were the natural rights of mankind,—"Life, Liberty and the Pursuit of Happiness." We might properly discuss the question, What do we owe to the birds? but that is a separate topic for a later time.
STRUCTURE AND HABITS OF BIRDS.
From a lecture by Frank M. Chapman, April, 1900.
HOW HAVE the various types of bird life come into existence? To understand this we must study the wings of the creature to learn its evolution from the early reptile-like type of bird. The most primitive use of the wing is as a hand, by which the bird may climb about. In contrast the albatross has the finest developed wings of any species which are fourteen feet across. The man-o'-war, however, is even a better example, perhaps, for although having a body no larger than a hen, it has wings which spread apart to a distance of seven or eight feet, enabling it to soar in the air for several days without touching the earth.
By intertwining the outer feathers of the wings some birds can remain stationary in the air for hours at a time, not once moving a wing. The razor-billed hawk is the nearest living representative of the extinct great hawk, a bird which, having small wings, could not fly, and soon became extinct. The penguin, with its flippers, can fly only on the water, and has to waddle when on land. Certain grebes which find their food in lakes have also lost their power of flight. This is true of some pigeons, auks, parrots, grebes, ducks and other birds which have not found it necessary to obtain their food by flying.
Wings are also used to express emotion. Many young birds, of which the oriole furnishes an example, cause their wings to quaver in supplication. Certain birds also make use of their wings as a musical organ, as is evinced in the whistling sound produced by the woodcock. Our nighthawk makes a booming sound with its wings by extending its outer quills as it dives earthward. A weapon is also found by some birds in their wings, the pigeon, hen and other of our common birds using their wings to strike with.
The foot shares with the wing the duties of locomotion. Birds with highly developed wings have poor feet. The swallow, an aerial bird, is an example. The chimney-swift has a tiny foot, but enormously developed wings, and if placed on a flat surface is unable even to support itself. All aquatic and terrestrial birds have excellently developed feet. The loon is so thoroughly aquatic that it cannot walk on land without the support of its breast and wings. The sea snipe has a foot especially fitted for swimming, and can be found a few hundred miles off the Atlantic coast in flocks of hundreds of thousands, perfectly at home in the water.
The foot is generally related to the length of the neck. The flamingo wades out into the water, and is able to duck its head and secure its food with the aid of its particularly constructed neck. In securing prey the foot also plays an important part. The great horned owl and the duck hawk have enormous grasping power in their claws. In our grouse or partridge a horny, fringe-like growth appears on the toes late in the fall, serving as a sort of snowshoe during the winter, by which the bird is enabled to walk on the surface of the snow. This growth is shed in the spring.
The bill is the most important organ of the four we are discussing. It has the offices of the hand. There is an almost limitless variation in its shape, admirably adapted in each instance to its food requirements. The fish-eating duck grasps its prey with a saw bill. The pelican catches its fish by diving from the air, often from distances of forty feet, and catches its fish in a bill an inch and a half in width. As it throws its head out in diving, it widens the rim of its bill and catches the prey in its curious pouch. The flamingo catches, with its food, mud and sand, which it expels through a curious straining apparatus. The woodcock has the power of curving up the upper portion of its bill, giving it the grasping power of a finger, which greatly aids it in probing for worms. The woodpecker uses its bill as a chisel. In southern Arizona the Californian woodpeckers have used the poles of the Western Union Telegraph Company in which to store acorns, and in some instances have bored large holes entirely through the poles. In those woodpeckers which feed on bark we find the tongue brush-like to swab up the sap. Where woodpeckers chisel the tongue is horny. In prying off cones from trees the cross-bill finds its apparently malformed tongue most helpful. In humming birds there is a marked variation in the bill, enabling them to feed on different sorts of flowers.