Eastern Spot-billed Duck

The Eastern spot-billed duck, or Chinese spot-billed duck (Anas zonorhyncha), presents itself as a species of dabbling duck, comparable in size to the familiar mallard. It boasts a scaly patterned body, complemented by a blue speculum, and is distinguished by a long neck and a bill tipped with a striking yellow spot. Adult ducks exhibit a mainly grey plumage with a paler head and neck, and a black bill that is brightly tipped with yellow. The wings, when viewed from below, are whitish with black flight feathers, and from above, they reveal a white-bordered green speculum. The male is devoid of an eclipse plumage, and juveniles appear browner and duller than their adult counterparts. Their legs and feet are a vivid orange, adding a splash of color to their otherwise muted tones.

Identification Tips

When identifying the Eastern spot-billed duck, look for the yellow-tipped bill and the long neck, which are particularly noticeable when the bird is at rest. The blue speculum is a key feature, along with the scaly patterned body. The duck measures 55–63 cm in length and 83–95 cm across the wings, with a body mass ranging from 790 to 1,500 grams. The species is darker and browner than the Indian spot-billed duck and resembles the Pacific black duck in body plumage. It lacks the red bill spot characteristic of its Indian counterpart.

Habitat

This species favors freshwater lakes and marshes situated in relatively open landscapes. It is a bird that thrives in environments where it can dabble for plant food, often foraging in the evening or at night.

Distribution

The Eastern spot-billed duck is a migratory bird, spending winters in Southeast Asia. It is known to be quite sociable outside of the breeding season, forming small flocks. Notably, the populations in Japan and the Russian Far East have extended their range northwards by over 500 km since the early 20th century, potentially as a response to global warming.

Behaviour

Outside of the breeding season, these ducks are gregarious and form small flocks. They are primarily nocturnal feeders, dabbling for plant food. During the breeding season, which varies with rainfall and water conditions but typically occurs between April and July, they nest on the ground in vegetation near water. The clutch usually consists of 7-9 eggs, and incubation commences after the last egg is laid to ensure simultaneous hatching. The ducklings, which hatch after about 24 days, are black with a yellow back and have a wider eyestripe compared to mallard chicks.

Song & Calls

Both male and female Eastern spot-billed ducks vocalize calls similar to those of the mallard. The female produces a loud quack, while the male emits a deeper, quieter sound.

Breeding

The Eastern spot-billed duck nests on the ground in dense vegetation near water bodies. The breeding season is influenced by local rainfall and water conditions, typically occurring between April and July. The clutch size is usually 7-9 eggs, and incubation begins after the last egg is laid, allowing for the synchronized hatching of chicks.

Similar Species

The Eastern spot-billed duck can be confused with the Indian spot-billed duck and the Pacific black duck. However, it can be distinguished by the absence of the red bill spot and its darker, browner body plumage.

Diet and Feeding

These ducks are dabblers, feeding on plant material. They are known to forage mainly in the evening or at night, taking advantage of the cover of darkness.

Conservation status

The IUCN Red List classifies the Eastern spot-billed duck as Least Concern, indicating that the species does not currently face a significant risk of extinction in the wild.