The Ferruginous Duck (Aythya nyroca) is a small, warmly chestnut-brown diving duck whose male shows a bright white eye and a white undertail. It measures roughly 38-42 cm in length with a wingspan of about 60-67 cm. The male is warm chestnut-brown on the head, neck and breast, with a striking white eye, a dark back and a contrasting white undertail; the female is duller brown with a dark eye but shows the same white undertail, which is often the surest field mark at a distance. In flight a broad white wing band is visible.
The species is mostly silent, though the displaying male can give a low, hissing call and the female a hard, grating "gärr". It breeds in shallow, vegetation-rich freshwater in southern and eastern Europe and Central Asia, and the world population has declined through drainage and the loss of wetlands, leaving it globally red-listed as Near Threatened. In Sweden it appears only as a rare visitor, usually as single individuals among flocks of other diving ducks on nutrient-rich lakes and ponds, with scattered records through the year concentrated in spring and autumn, each sighting drawing attention from birdwatchers. It does not breed regularly in Sweden; in its core range it builds a well-hidden nest in dense shoreline vegetation near water, and the female lays usually 7-11 eggs. Strongly tied to shallow, vegetation-rich wetlands, it is correspondingly sensitive to drainage. It forages by diving, feeding on a mix of aquatic plants, seeds and aquatic invertebrates such as insect larvae, snails and crustaceans, favouring shallow, vegetated water.
Read about this species in Swedish →