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 those which are deficient in song by
giving them a superior beauty of plumage. As the offices of courtship