The length of a bird's life very much depends on the care which is taken of it. There are some parrots which have lived more than a century; and nightingales, chaffinches, and goldfinches have been known to live more than twenty-four years in a cage. The age of house birds is so much the more interesting, as it is only by observing it that we can know with any degree of certainty the length of birds' lives in general. Thus house birds are of importance to the naturalist, as giving him information which he could not otherwise acquire. It is worthy of remark, that the quick growth of birds does not prevent their living much longer than quadrupeds. The length of life with these is estimated to be six or seven times longer than the time which they take to grow: while birds live fifteen, twenty, and even thirty times longer. This length of life is sometimes attributed to the substance of which the bones are composed being much more loose and light, and consequently remaining porous longer than those of quadrupeds. Some swans have lived three hundred years. BIRD CATCHING. We are furnished with house birds by the bird catchers and bird sellers; the latter procure foreign birds, and teach them, the former the indigenous ones. A good bird catcher ought to know not only the different modes of taking birds, but also all the calls for attracting the different species and sexes: the call notes vary very much among house birds, according to their passions and wants; thus the common chaffinch, when calling its companions, often repeats _iack_, _iack_; when expressing joy, _fink_, _fink_, which it also does when angry, though louder and more quickly; whilst its cry of sorrow is _treef_, _treef_. The science of bird catching consists in studying these different languages well, and it will ensure success. As each species of bird requires a different mode, I shall mention the various methods in the course of the work, and shall here only speak of bird catching in general. The first thing to know is the proper time to take birds. For birds of passage, impelled by cold and want of food to change their climate, nets should be spread in spring and autumn; erratic birds, which change their place merely in search of food, may be taken, some in winter, some in spring, and others in autumn; those birds which never quit their native place may be taken at any season, but more easily in winter, when they assemble in small flocks.