Page:Natural History, Birds.djvu/306

Rh have probably a connection with the loudness or intonation of the voice. The gizzard is large and muscular, and especially in those species which are more terrestrial, living largely on grain. They mostly nestle on the ground, but some on trees, and lay numerous spotless eggs; the young are at first covered with down, and are able to run and to swim as soon as they are hatched.

The remarkable laminated structure at the edges of the mandibles in the birds of this Family, and its connection with their habit of feeding, are thus commented on by Mr. Swainson. "The inconceivable multitudes of minute animals, which swarm in the northern seas, and the equally numerous profusion inhabiting the sides of rivers and fresh waters, would be without any effectual check upon their increase, but for the Family of the Ducks. By means of their broad beak, as they feed upon very small and soft substances, they capture, at one effort, considerable numbers. Strength of substance in this member is unnecessary; the beak is therefore comparatively feeble, but great breadth is obviously essential to the nature of their food. As these small insects, also, which constitute the chief food of the Anatidæ, live principally beneath the surface of the mud, it is clear that the beak should be so formed as that the bird should have the power of separating its nourishment from that which would be detrimental to the stomach. The use of the laminæ thus becomes apparent; the offensive matter is ejected between their interstices, which, however, are not sufficiently wide to admit the passage of the insect-food at the same time. The mouthful of stuff brought from the bottom is, as