Anatidae is the duck, geese and swan family of birds of the order Natatores. They are characterized by a thick, broad beak, high at the base, covered with a thin membranous skin and ending in a nail-like horny tip; the edges of the mandibles are cut into thin parallel ridges, or toothed; the wings are moderate; the legs placed not very far behind; the feet are four-toed and palmated; the hind toe is free, placed high on the tarsus. They feed on grass and aquatic weeds, worms, insects, molluscs and small fish. Research Anatidae