The birds of prey, such as hawks, owls, and eagles, have large, strong, and sharply curved talons and powerful digits, and a sad use they make of them in clutching small birds and animals. The claws of the woodpeckers and other climbing birds are stout and extremely acute, just as they should be for clinging to the bark of trees. In short, the structure of a bird's foot, whatever may be the species of fowl, furnishes most conclusive evidence of adaptation in the world of Nature.