Page:Natural History, Birds.djvu/215

202 at a representation of the skeleton in a climbing position: the low keel allowing the bird to place its body close to the tree, to bring its centre of gravity in a perpendicular line before the points of support, and thus materially to diminish the labour of, and the strain upon, the muscles of the legs and thighs."

The beak is hard and compact in its texture, in some species nearly resembling ivory, stout at the base, and tapering, with angled sides, to the point, which is sharpened to an edge, like a small chisel; or perhaps, the whole form may be likened to a short but stout iron nail with a flattened point. The value and efficiency of this organ will be apparent when the economy of the bird is known; it obtains its food, consisting of the larvæ of wood-boring insects, by chiselling away the bark and surrounding wood, until the subtle grub is exposed. The head, then, acts as a hammer, of which the beak is the face or point, and the curved neck the handle, and being moved by muscles of great energy, the sharp and wedge-like beak-tip is propelled against the tree in a succession of strokes given with extraordinary force and rapidity.

But as the labour required actually to chisel out every grub on which the Woodpecker subsists, would be immense, effective as its weapon is, and rapid as is its execution, there is yet another admirable contrivance which we must notice, by which the prey being once exposed, is dragged from his tortuous hiding-places, and inmost crevices. The tongue is tapered to a slender horny point, and its length is extraordinary: for it passes behind into two cartilaginous filaments, which passing under