Indian Spot-billed Duck

The Indian spot-billed duck, Anas poecilorhyncha, is a large dabbling duck that is a non-migratory breeding species across freshwater wetlands in the Indian subcontinent. It is roughly the size of a mallard and exhibits a scaly patterned body with a green speculum bordered by white. The male is distinguished by a red spot at the base of the bill, which is less conspicuous or absent in the female.

Identification Tips

When observing the Indian spot-billed duck, look for the characteristic green speculum with a white base and the white tertials that form a stripe on the side. The male's red spot at the base of the bill is a key identifier, while the female is similar but slightly smaller. In flight, the broad white band at the base of the green speculum is a distinctive feature.

Habitat

These ducks favor freshwater lakes and marshes in fairly open country. They tend to avoid vast expanses of open water, preferring medium-sized wetlands with some vegetation cover.

Distribution

The Indian spot-billed duck is a resident species throughout Pakistan and India. Some individuals may migrate, as evidenced by a ringed specimen from Rajasthan recovered near Novosibirsk. The species has expanded its range northwards by over 500 km since the early 20th century, potentially in response to climate change.

Behaviour

Indian spot-billed ducks are gregarious outside the breeding season, forming small flocks. They are dabbling ducks, feeding mainly in the evening or at night. They are capable of taking off almost vertically from the water when disturbed.

Song & Calls

Both males and females produce calls similar to those of the mallard. Their vocalizations are an important aspect of their social behavior.

Breeding

The breeding season varies with rainfall and water conditions but typically occurs from July to September in northern India and November to December in southern India. The species may raise multiple broods. Nests are constructed on the ground, hidden in vegetation near water, and contain 8-14 eggs. Incubation begins after the last egg is laid, and chicks hatch after about 24 days.

Similar Species

The eastern spot-billed duck is similar but darker and browner, with body plumage more akin to the Pacific black duck. It lacks the red bill spot and has a blue speculum.

Diet and Feeding

Indian spot-billed ducks feed on plants, including rice crops, and invertebrates such as snails. They can become infected by trematodes through snails, which then emerge as adult trematodes after about 21 days.

Conservation status

The Indian spot-billed duck is currently listed as Least Concern on the IUCN Red List, indicating that it is not at immediate risk of population decline.