Most of these birds live in societies, which are often exceedingly numerous, inhabiting high northern and southern latitudes. The distinguishing characteristic of the family of the _anatidæ_ is the _bill_, which is usually of a flattened form, covered with a soft skin, and furnished at the edges with a series of _lamellæ_, which serve to sift or strain the mud in which they generally seek their food. The feet are furnished with four toes, three of which are directed forward, and united by a web; the fourth is directed backward, usually of small size, and quite free. They are admirable swimmers, and live and move on the water with the utmost security, ease, and grace. Such is their adaptation to this element that the young, immediately after being hatched, will run to it, and fearlessly launch themselves upon its bosom, rowing themselves along with their webbed feet, without a single lesson, and yet as dexterously as the most experienced boatman. They are generally inhabitants of the fresh waters, and for the most part, prefer ponds and shallow lakes, in which they can investigate the bottom with their peculiar bills, without actually diving beneath the surface; yet at some seasons they are found along the borders of the sea. Their food generally consists of worms, mollusca, and aquatic insects, which they separate from the mud by the agency of the lamellæ at the margin of the bill; but most of them also feed upon seeds, fruits, and other vegetable substances. THE WILD DUCK. This bird, known also by the name of _mallard_, is the original of all the domestic varieties. It is twenty-four inches long, and marked with green, chestnut and white. Wild ducks are gregarious in their habits, and generally migrate in large flocks. The males are larger than the females, and the latter are also usually of a more uniform and sober tint. It is an inhabitant of all the countries of Europe, especially toward the north, and is also abundant in North America, where it is migratory, passing to the North in Spring, and returning to the South in autumn. It frequents the lakes of the interior, as well as the sea-coasts. It is plentiful in Great Britain at all seasons, merely quitting the more exposed situations at the approach of winter, and taking shelter in the valleys; or, in case of a severe winter, visiting the estuaries. [Illustration: WILD DUCK.]