The Probert Encyclopaedia of Nature

DUCK

Duck is the name common to all the web-footed birds constituting the Linnaean genus Anas, now raised into a sub-family Anatinae, and by some naturalists divided into two sub-families Anatinae and Fuligulinas, or land-ducks and sea-ducks. The ducks are very numerous as species, and are met with all over the world. They are often migratory, going northward in summer to their breeding-places. Their food is partly vegetable, partly animal.

The common mallard or wild-duck (Anas Boschas) is the original of the domestic duck. In its wild state the male is characterized by the deep green of the plumage, of the head and neck, by a white collar separating the green from the dark chestnut of the lower part of the neck, and by having the four middle feathers of the tail recurved.
Research Duck