The white-backed duck (Thalassornis leuconotus) is a waterbird of the family Anatidae. It is distinct from all other ducks, but most closely related to the whistling ducks in the subfamily Dendrocygninae, though also showing some similarities to the stiff-tailed ducks in the subfamily Oxyurinae. It is the only member of the genus Thalassornis.
These birds are well adapted for diving. On occasions they have been observed to stay under water for up to half a minute. They search especially for the bulbs of waterlilies, but also seeds and leaves of waterlilies and other water plants and the young feed on lake flies larvae as well. From danger, they also escape preferentially by diving; hence, the namesake white back is hardly visible in life. Their habitat consists of lakes, ponds, swamps and marshes where they are well camouflaged against predators.
Source : Wikipedia