The eggs of all birds are edible, but birds differ greatly in the number of eggs that they lay and in the disposition to lay them in places provided for the purpose. So, nearly all who keep birds for their eggs keep fowls, which are the most prolific and most docile, and hens' eggs are the staple eggs in the markets.
The feathers of birds are used for pillows and beds, for feather dusters, and in various ways for ornament. Except in the case of the ostrich, however, the value of the feathers of domesticated birds is so small that no one grows birds primarily for their feathers. On the other hand, those who keep birds for pleasure find their greatest enjoyment in breeding them with colors and markings difficult to produce. Choice specimens of fancy-bred birds bring prices many times greater than the value of their flesh and eggs for food and of their feathers for use or ornament. Fancy feathers have no more value than others except on the living birds.
While those who keep birds for pleasure nowadays give most attention to breeding fancy stock for exhibition, several kinds of pigeons are kept to entertain by their flying performances; and—outside of the limited class of those who breed them especially for exhibition—canaries are valued according to ability to sing. The brutal sport of cockfighting was a popular pastime with our ancestors until prohibited by law, and is still prevalent in many lands. In early times birds of prey were captured when very young and carefully trained to hunt for their masters. Under the feudal system there were regulations prescribing the kinds of birds which different classes of men might use in this way: the eagle and vulture were for emperors only; the gyrfalcon for kings; the lesser falcons for nobles; the harrier for esquires; the merlin for ladies; the goshawk for yeomen; the kestrel for servants; the sparrow hawk for priests.
Much of the value of various kinds of poultry comes from their ability to destroy insects which damage vegetation, and to maintain themselves on these and on foods not available for the larger domestic mammals. The services of poultry in this respect being limited to those insects that can be secured from the ground, and to areas on which the birds can live safely and do no damage to crops, we are dependent upon wild aërial birds to keep insect life in check on trees and high bushes and on land not occupied by poultry.
Place of wild birds in civilization. As no insect-eating aërial birds have been domesticated, the preservation of wild birds that destroy insects is of as much importance to man as the production of domestic birds. Indeed, the wild birds are much more valuable to us in the wild state than they would be if domesticated.
In nature species prey upon each other—the lowest forms of life upon inorganic and decayed matter, the higher forms upon the lower, the larger creatures upon the smaller, the savage upon the defenseless. Fertile lands not only produce luxuriant vegetation but teem with insect life, which, if not kept in check, would soon destroy that vegetation. In tropical and semitropical regions there are mammals, some of them quite large, which feed upon insects. In temperate regions where insects are not to be obtained during the winter, there would be no adequate check upon their increase and the consequent destruction of vegetation if it were not for the vast numbers of insect-eating migratory birds which come to these regions for the summer. Necessary as these birds are to vegetation on uncultivated lands, they are more necessary in cultivated fields, orchards, and gardens where the crops are more attractive to insects than the mixed vegetation on wild lands. As insect destroyers the domestic birds that are kept on cultivated lands only fill the place of the nonmigratory wild birds that have been driven away or exterminated. So it is to the interest of every one to protect insect-eating wild birds, for although these birds may do some damage to crops, their service usually more than pays for it.
Classes of domestic birds. There are three classes of domestic birds—poultry, pigeons, and cage birds. The poultry class comprises land and water birds and contains nine kinds—fowls, ducks, geese, turkeys, guineas, peafowls, pheasants, swans, and ostriches. The pigeon class has but one kind, the pigeon, which is the only aërial bird domesticated for economic purposes. The cage-bird class has as its most important representative the canary. The other birds of this class have never been popular in America.
The question of increasing the number of species of birds in domestication interests many people. There is a general impression among those not familiar with the commercial aspect of aviculture that many more species might be domesticated. While it is true that many birds capable of domestication have not been domesticated, there are few of these that would serve any purpose not better served by some species already domesticated. It will be shown as the different kinds and varieties of domestic birds are discussed that the most useful kinds are always the most popular, and that many others are kept principally as ornaments. The number of ornamental creatures that can be kept in domestication is limited, for as a rule animals, like people, must earn their living.