Ferruginous Duck

The Ferruginous Duck, known scientifically as Aythya nyroca, is a medium-sized diving duck hailing from the vast expanses of Eurosiberia. The males are adorned with a rich, dark chestnut plumage on their heads, breasts, and flanks, which is set off by the stark white of their undertail coverts. When in flight, their white bellies and underwing patches become conspicuous. Females present a more subdued palette, being duller and browner. A notable feature of the male is its yellow eye, while the female's eye is dark.

Identification Tips

To identify the Ferruginous Duck, look for the male's distinctive yellow eye and rich chestnut coloring. In contrast, the female will have a dark eye and a browner hue. When the bird takes to the air, observe the white belly and underwing patch that become visible, aiding in its identification.

Habitat

The Ferruginous Duck shows a preference for shallow freshwater bodies teeming with rich submerged and floating vegetation. The margins of these waters are often densely populated with emergent vegetation. While it may occasionally inhabit saline or brackish pools or wetlands, during migration and wintering, it is also known to frequent coastal waters, inland seas, and large open lagoons.

Distribution

This duck's breeding range stretches from Iberia and the Maghreb eastward to western Mongolia, and southward to Arabia. However, in the western part of its range, it has become scarce and localized, with some countries reporting local extirpation. In winter, the species disperses throughout the Mediterranean Basin and the Black Sea, with some migrating into sub-Saharan Africa via the Nile Valley. Eastern populations winter in South and Southeast Asia.

Behaviour

Ferruginous Ducks are sociable, yet they are less so than other species within the Aythya genus. In regions where they are common, they may form large flocks in the winter, often mingling with other diving ducks like tufted ducks and common pochards. They begin pairing from January, and during courtship, males may exhibit a tail-curling behavior that dips the tail into the water, highlighting the white undertail coverts. They may form colonies in protected areas, such as islands, sometimes alongside gulls, or nest singly in more concealed locations when less common.

Breeding

The nesting period commences at the end of April or the start of May. Nests are constructed on the ground near water or occasionally as floating structures amidst emergent vegetation. The incubation of eggs spans 25–27 days, and the young take 55–60 days to fledge.

Diet and Feeding

These ducks primarily feed by diving or dabbling. Their diet consists mainly of aquatic plants, supplemented with molluscs, aquatic insects, and small fish. They are known to feed nocturnally and exhibit both upending (dabbling) and diving behaviors in their quest for sustenance.

Conservation status

The Ferruginous Duck faces threats from habitat degradation and destruction due to a variety of human activities, including impoundment, drainage, pollution, and mismanagement. The introduction of non-native species, such as grass carp, has also contributed to habitat degradation by reducing plant and animal biomass. Climate change-induced droughts pose additional threats, particularly in the drier parts of their range. Disturbance from fishing boats and anglers can lead to breeding site abandonment or disrupted breeding timing, especially in populated areas like Western Europe. Despite protection in most European countries, illegal and accidental hunting continues to threaten this species. The Ferruginous Duck is covered by the Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA). Local conservation efforts include the protection of breeding habitats in Armenia as part of the network of Emerald Sites under the Bern Convention.