This is a large duck. Both sexes have blue-grey bills and grey legs and feet. The drake is more striking, having a thin white stripe running from the back of its chocolate-colored head down its neck to its mostly white undercarriage. The drake also has attractive grey, brown, and black patterning on its back and sides. I took this picture at Mangalajodi, Odisha, India during my recent visit in the month of January 2020.