This is a white-faced whistling duck. It has a wide-spread range in both the Old World and New World. In the Old World it is found in Africa and Madagascar, and in the New World it is found in the Caribbean islands and Central and South America. It is called a whistling duck because its call sounds like it is whistling. Its scientific name is Dendrocygna viduata.
We saw the duck in these pictures at the National Zoo in Washington, D.C. We went there this summer.