Black-bellied Whistling Duck (immature)

Black-bellied Whistling-Ducks are dark overall: a chestnut breast and black belly are set off by a bright-pink bill and legs, grayish face, and broad white wing stripe, also visible in flight. Immatures are duller than adults, with a dark bill, pale breast, and mottled black belly.

http://www.allaboutbirds.org/guide/black-bellied_whistling-duck/id