A medium-sized duck, similar to female Mallard in appearance, but smaller and darker. Males lack the green head and curled black tail feathers of male Mallards. Both sexes have spotted tail feathers. The bill is dark greenish, with an orange tip in some females. Pure Hawaiian Ducks occur only on Kauai and montane streams and ponds on Hawaii Island. Most or all individuals on other islands are Mallard-Hawaiian Duck hybrids. Occurs in ponds, marshes, taro fields, and streams.