to sing, another has ceased, so that, at whatever time of the year the traveller stops, he hears but few birds engaged in song.
In the temperate latitudes, on the contrary, as soon as the birds arrive, they commence building their nests, and become musical at the same time. If a stranger from a tropical climate should arrive in this country in the spring, and remain here during the months of May and June, he would hear more birds singing together than he ever heard at once in his own clime; but were he to arrive about the middle of July, when the greater number of our birds have discontinued their songs, he would probably, if he knew the reputation of the Northern birds, marvel a little at their silence. If there are as many birds singing at one time during the whole year, in the hot climates, as we hear in this country in the latter half of summer, the greater average would appear to be on the side of the former.
It may also be remarked, that the singing-birds of the tropics are not so well known as those of temperate latitudes which are inhabited by civilized men. The savages and barbarians, who are the principal inhabitants of hot countries, are seldom observant of the habits or the voices of the singing-birds. A musician of the feathered race, as well as a harpist or violinist, must have an appreciating audience, or his powers can never be made known to the world. But even with the same audience, the tropical singing-birds would probably be less esteemed than songsters of equal merit in the temperate latitudes; for, amid the stridulous and deafening sounds made by the insects in warm climates, the notes of birds would be scarcely audible.
We are still inclined to believe, however, that there is a larger proportion of musical birds in the temperate than in the torrid zone, because in the former region there are more of those species that build low and live among the grass and shrubbery, and it is well known that the singing-birds are mostly of the latter description. In warm climates the vegetation consists chiefly of trees and tall vines, forming together an umbrageous canopy overhead, with but a scanty undergrowth. In temperate latitudes the shrubbery predominates, especially in the most northerly parts. Moreover, the grasses that furnish by their seeds a great proportion of the food of the smaller birds are almost entirely wanting in the torrid zone.
The birds that live in trees are remarkable for their brilliant plumage; those that live upon the ground and in the shrubbery are plainly dressed. This is a provision of Nature for their protection, as the ground-birds must have a predominance of tints that resemble the general hues of the surface of the earth. I do not know a single brightly-plumed bird that nestles upon the ground, unless the bobolink may be considered an exception. They are almost invariably colored like sparrows. The birds that inhabit the trees, on the other hand, need less of this protection, though the females are commonly of an olive or greenish yellow, which harmonizes with the general hue of the foliage, and screens them from observation, while sitting upon the nest. The male, on the contrary, who seldom sits upon the nest, requires a plumage that will render him conspicuous to the female and to the young, after they have left their nest. It is remarkable, that Nature, in all cases in which she has created a difference in the plumage of the male and female, has used the hues of their plumage only for the protection of the mother and the young, for whose advantage she has dressed the male parent in colors that must somewhat endanger his own safety.
The color of the plumage of birds seems to bear less relation to their powers of song than to their habitats; and as the birds that live in trees are commonly less tuneful, they are more brilliantly arrayed. The bird employs his song in wooing his mate, as well as in entertaining her after she is wedded; and it is not unlikely that Nature may have compensated
