Despite their name, Brazilian Teals are native not only to Brazil but to most of eastern South America from Colombia/eastern Peru to northern Argentina

The male Brazilian Teal has a red beak, white cheeks and an extended metallic teal-blue-green wing speculum

Beak of male turning to red

White cheek with black beak indicates young male?

The female Brazilian Teal has no white cheek and a black beak

The female has a white spot at base of bill, white eyebrow and chin

Size comparison with female Ringed Teal

The male has a red bill and the female a black bill with white spot at base and white eyebrow. Above are the Greater Brazilian Teal (A. b. ipecutiri ) which lives in southern Brazil, northern Argentina and Paraguay,

 south of the range of the nominate/Lesser sub-species.