Ferruginous Duck

The Ferruginous Duck is a small diving duck, smaller than the Mallard and Common Teal. Sexual dimorphism is less pronounced than with them. The adult male is typical. He is tricolored, black, chestnut and white. What is striking is the chestnut-mahogany color of the head, neck, chest and flanks. Also striking are the white undertails separated from the chestnut flanks by a vertical black bar. The upper parts are black-brown. The white belly is only visible in flight. The head is special. The forehead is flat and the crown rounded, but it has erect feathers that give it a distinctly rounded appearance. The iris is white. The rather long beak is gray-blue with a black tip and an indistinct whitish sub-terminal ring. In flight one can not miss the clear white wingbars on the primary and secondary remiges of the wings, dark otherwise. Viewed from below, one can clearly see the underside of the wings light edged with black and the contrast between the white abdomen and its chestnut context.
The adult female is duller, browner and could be mistaken for an adult female Common Teal. She is distinguished by the lack of a topknot and the brown eye. In addition, the white undertail is clearly delineated as in the male. The female Teal sometimes has white undertail, but never to this extent. She does, however, have a pale face at the base of the beak, which the nyroca never shows.
The male in eclipse looks very much like a female but retains the white iris. The juvenile also looks like an adult female but its plumage is less warm, especially on the head. His undertails are not pure white, his belly is stained with brown and his beak is gray. He too can be mistaken for a female-type Teal.
The Ferruginous Duck occasionally hybridizes with the Mallard and Common Teal, producing hybrids that can be identified as such as they are adult males (see the gallery).It's more difficult with Ferruginous Duck hybrids of female type.