Insects and their larvae form their nourishment, which they seek in the trunks and clefts of trees. Their tongue is wonderfully suited for this purpose. It is very long, and, by a peculiar mechanism, can be projected out far enough to reach objects three or four inches away. The beak is terminated by a horny point bristling with small hooks. In many species it is overlaid with a sticky substance secreted by two glands, the effect of which is to catch the insects which it touches. Whenever the Bird darts this tongue into the crevices, it draws it out more or less laden with insects. If it perceives an insect that it cannot reach by means of this organ, it uses its strong beak; striking the tree with redoubled blows, it cuts the bark, breaks an opening, and seizes the coveted prey. It often also taps with its beak to sound a tree, and assure itself that there is no recess in the interior which would serve as a refuge for its prey. If the trunk is hollow, it examines all parts to find an entrance to the cavity. When it has discovered it, it introduces its tongue; and if the canal is not large enough to permit it to explore the hiding place with success, it increases the size of the aperture. It is not only to seek for food that Woodpeckers make holes in trees, but also to form secure hiding places for their nests. Some species, it is true, select the openings which they find, but others hollow out their nesting places according to their tastes. When such is the case, they select soft-wood trees, such as willow, aspen, etc. The cavity which they bore to where the nest is placed is generally so oblique and so deep that perfect darkness surrounds them. This is doubtless a measure of security against small Mammals, especially the rodents, the natural enemies of their family. The mother deposits her eggs upon a bed of moss or the dust of worm-eaten wood. The young Birds grow slowly, and receive for a long time the care of their parents. Woodpeckers are generally considered noxious Birds, because they are supposed to injure the trees of forests and orchards, and for this reason a relentless war is made against them. They should, on the contrary, be protected; for they destroy innumerable insects, the real enemies of timber, and never touch a sound limb, for in it their food is not to be found. There are a great number of species of Woodpeckers known, which are spread over the two continents. The principal are the Ivory-billed Woodpecker, a native of America; the great Spotted Woodpecker and the Downy Woodpecker.