Bird Facts

Birds, warm-blooded animals, easily distinguished from other vertebrates by their shape, by the feathers that cover their bodies and by their wings. Birds usually live in pairs, rearing their young in homes which they make themselves, though there are some remarkable exceptions to this rule. All birds lay eggs from which young are hatched. In the higher orders the young are naked when they break from the shell and must be cared for and fed by the parents, but in some of the lower species the little ones are covered with tiny hairs and in others covered with a complete suit of feathers before they hatch. In the latter case the young are able to take partial care of themselves very soon after they appear. The eggs vary in number from two to several dozen, seeming to be proportioned to the dangers the young are to meet, but being practically the same number at every sitting of each species. The eggs which are hatched by heat are sometimes buried in rotting vegetation, or in the sand under the hot sun, but more frequently they are laid in artificial nests or in some natural receptacle, and are there brooded and kept warm by the body of the female until the chick matures and emerges. This is usually a period of from two to three weeks.

Nothing is more wonderful than the flight of birds. Their wing power is extraordinary, but the speed with which they fly has doubtless been exaggerated. Their endurance is much more surprising. Some of the smallest and apparently feeblest of birds, that usually confine their flight to short dashes from bush to bush, may during their migrations cover in a single flight distances ranging from five hundred to two thousand miles. In order that the body, relatively so heavy, may be carried through the air, the muscles which move the wings must be very strong and have a strong frame for their attachment. The frame is furnished by the wide breast bone. But strong muscles alone would be insufficient were there not in the body air cavities, which sometimes extend even into the bones and feathers. The wings, which are the chief organs of flight, are modified fore limbs, corresponding to the arms of a human being. From the body of the wings grow strong feathers with heavy quills, making a broad surface with which the bird can beat the air. The heavy quills are covered both above and below with short feathers, which prevent the air from passing through and make it slide readily off. The tail does not help much in flight, but it is rather a rudder by which the bird steers itself and holds its body level. The feathers which cover the entire body are small and overlap, but they do not grow uniformly everywhere, being distributed in certain definite patches or areas.

The food of birds varies widely according to the species. No living bird has teeth, but the beak of each species is fitted to handle the food which it eats. No arrangement provides for the chewing of the food, so the bird's organs of digestion are peculiar. After the food is swallowed it finds lodgment first in the crop, a large sack at the bottom of the gullet. Here the food is soaked and softened for some time and then paused on to the gizzard, a kind of stomach, with exceedingly strong muscular walls and tough, hard, wrinkled lining. Here the food is ground fine by vigorous rubbing, sometimes aided by small pebbles and gravel eaten by the bird. Naturally the meat-eating birds have smaller gizzards, with thinner muscular coats, and in some species there is no gizzard at all. The quantity of food required by birds is enormous and in this necessity lies their chief value to the horticulturist.

Their sense of sight is keen, and in some species it is little less than marvelous. The eye is very much like that of a human being, but it has a third lid, which can be drawn at will so as partially to shut out the light. The nostrils open through the upper part of the beak, and in some birds the sense of smell is exceedingly keen. Although birds have no external ears, yet most of them are extremely sensitive to sound. The senses of taste and touch are dull, yet both are possessed by the bird. While not a large number of birds can be said to sing, yet songs are among the most pleasing and attractive of their characteristics. Some are able to utter only discordant, disagreeable notes, but others, like the crow, seem to have developed a language of their own, and not a few can be taught to speak words. Ordinarily, only the male birds can sing, and those which are most brilliant in plumage are the poorest singers. In general, the singing birds are small and lively, living principally upon grains and fruits.

A remarkable trait of birds is their instinct for returning directly to their homes after having been away, as may be seen in the return of the homing pigeon and the return of many species from the winter migration to old homes in the north. The toes of a bird are fitted for clinging to twigs and branches, for scratching in the ground, for clasping and holding prey and, when bordered by a broad margin or connected by webs, for swimming. The muscles in the legs of perching birds are so arranged that when the bird sits, its toes are bent and cannot be opened until the bird rises again. This arrangement prevents it from falling from the twigs while asleep. Most young birds are fed upon insect food, and as they appear when insect pests are at the very worst, man is usually much benefited by their hearty appetites. The incredible number of insects eaten in a single day show how great a difference a few birds make. But the benefits conferred upon man by the birds are not confined solely to the extermination of insects. Many are excellent and even delicious food, and from the wild birds have come various domestic fowls which, because of their eggs and flesh, are among man's most valuable living possessions. The pleasure given by the beautiful colors, charming habits and sweet songs of the birds deserves more than a passing mention.