Anseriformes / Anatidae / Anas
Eastern Spot-billed Duck
Anas zonorhyncha · 斑嘴鸭
Introduction
A dabbling duck species breeding in East and Southeast Asia, formerly considered a subspecies of the Indian spot-billed duck. It inhabits freshwater lakes and marshes in open country, feeding mainly in the evening or at night.
Description
Measures 55–63 cm (22–25 in) in length with a wingspan of 83–95 cm (33–37 in) and body mass of 790–1,500 g (1.74–3.31 lb). Plumage is mainly grey with a scaly pattern, paler head and neck, and bright orange legs and feet. The bill is black with a bright yellow tip. Wings show a blue speculum bordered by white; flight feathers are black below. Males lack eclipse plumage. Juveniles are browner and duller than adults.
Identification
Distinctive at rest due to long neck and black bill with yellow tip. Darker and browner than the Indian spot-billed duck, lacking the red bill spot and possessing a blue speculum. Body plumage resembles the Pacific black duck. Vocalizations are similar to mallards: females produce a loud quack, while males make a deeper, quieter sound.
Distribution & Habitat
Breeds in East and Southeast Asia, wintering in southern China and possibly further south. Populations in Japan and the Russian Far East have expanded northwards by over 500 km since the early 20th century. Occasionally occurs as a rare vagrant in the Aleutian Islands, Alaska. Habitats include freshwater lakes and marshes.
Behavior & Ecology
Gregarious outside the breeding season, forming small flocks. Feeds by dabbling for plant food, primarily in the evening or at night. Breeding occurs between April and July, depending on rainfall and water conditions. Nests on the ground in vegetation near water. Clutch size is usually 7–9 eggs. Incubation lasts about 24 days, beginning after the last egg is laid. Chicks are black with a yellow back and a wider eyestripe than mallard chicks. Both sexes undergo a complete postnuptial moult, dropping all wing feathers simultaneously. Hybridization with mallards occurs in eastern Russia.
Source: Wikipedia · CC BY-SA 3.0
Taxonomy
- Order
- Anseriformes
- Family
- Anatidae
- Genus
- Anas
Distribution
breeds southeastern Russia and eastern Mongolia eastward to Sakhalin and eastern China, Korean Peninsula, and Japan; winters to southern China, Taiwan, and Philippines
Data Sources
Species description from Wikipedia, licensed under CC BY-SA 3.0.
Bird images and sounds sourced from GBIF, contributed by citizen scientists worldwide under Creative Commons licenses.
Taxonomy data from AviList 2025.
