zarro-grande Aythya valisineria

Attractive duck with distinctive triangular head; forehead slopes seamlessly into the long bill. Males are white-bodied with black chest, reddish-brown head, and red eye. Females are dull grayish-brown with unique head profile and dark brown eye. Breeds in lakes and marshes. Winters in any large body of water with submerged aquatic vegetation on which to feed. Dives frequently, searching for vegetation and invertebrates. Often gathers in large flocks in nonbreeding season.