Domestic Mallard (Anas platyrhynchos var. domesticus, 家鸭).
Most likely the mallard was first domesticated in southern China. Where there are lakes with healthy vegetation, infrequent disruptions and little interference from people or other animals (I suspect local moorhens keep them out of their own favoured territories) there are often a few individuals ducks. How long since their ancestors have escaped domesticity one invariably wonders.