[AS.] The largest and most graceful of all swimming birds. When full-grown its feathers are white, but when young they are bluish-gray. Its feathers are thick and oily, and cast off water. Its feet are webbed, and it swims rapidly. Its legs are placed far back, and this gives it a waddling walk. Its neck is longer than its legs, and so it can reach its food. It feeds on roots and seeds of water-plants, and is fond of worms, small fishes, and snails. Its nest is built of grass and reeds on the banks of rivers or lakes. The swan is found all over the world, and being beautiful on the water, is when tame kept on ponds and ornamental waters. The black swan of Australia has a red bill crossed with a white band. The South American black-necked swan has a bright rose-colored double knob on its bill.