Black-bellied Whistling Duck

The Black-bellied Whistling-Duck is a boisterous duck with a brilliant pink bill and an unusual, long-legged silhouette. In places like Texas and Louisiana, watch for noisy flocks of these gaudy ducks dropping into fields to forage on seeds, or loafing on golf course ponds. Listen for them, too—these ducks really do have a whistle for their call. Common south of the U.S., Black-bellied Whistling-Ducks occur in several southern states and are expanding northward.
http://www.allaboutbirds.org/guide/Black-bellied_Whistling-Duck/id