Introduction
The White-winged Duck, also known as the White-winged Wood Duck, is a large forest-dwelling waterfowl species found in parts of South and Southeast Asia. Its accepted scientific name is Asarcornis scutulata. Once more widespread, it now survives in small, fragmented populations associated with mature wetland and swamp-forest habitats. The species is listed as Critically Endangered on the IUCN Red List.
Physical Description
The White-winged Duck is a large, robust duck measuring approximately 66–81 cm in length. Adults have a dark body with a greenish metallic sheen, a pale head and upper neck marked with variable black spotting, and chestnut-brown lower parts. The white upper-wing coverts create a conspicuous pale patch in flight, contrasting with the darker flight feathers.
The bill is orange to yellowish and mottled with black, while the legs are orange-yellow. Adult males are generally larger than females and develop a swelling or knob at the base of the bill during the breeding season. Females are slightly smaller and usually have more densely mottled heads and upper necks.
Juveniles are duller and browner than adults, with less extensive white on the head and neck. They nevertheless retain the characteristic white wing patches, which helps distinguish them from some superficially similar dark ducks. Plumage can vary geographically. Birds from Sumatra may show unusually extensive white plumage, and the degree of white varies considerably between individuals.
Range and Habitat
The White-winged Duck is resident rather than a regular long-distance migrant. Its historical range extended from north-eastern India through mainland Southeast Asia to Indonesia, including Sumatra. The species has disappeared from, or become extremely scarce in, much of its former range. Remaining wild populations are concentrated in parts of north-eastern India, northern Myanmar, western Thailand and Sumatra, although the precise distribution continues to be refined through field surveys.
It is strongly associated with mature, humid forest and wetland systems, including swamp forest, shaded ponds, oxbow lakes, slow-flowing streams and other quiet freshwater bodies with dense vegetation. It may travel between forest roosts and more open feeding areas such as swamps, ponds and rice fields, sometimes flying several kilometres between them.
The species is a specialist of relatively undisturbed habitats. Deforestation, drainage, wetland conversion, forest fragmentation, disturbance and the degradation of slow-moving freshwater systems have greatly reduced suitable habitat. Local populations may persist only where forest cover, secluded water and protection from hunting remain available.
Behaviour and Diet
White-winged Ducks are generally secretive and are often encountered singly, in pairs or in small groups. They are most active around dawn and dusk, with feeding activity also taking place at night. During the day, they commonly rest in forest cover or on shaded water. Birds may become more strictly nocturnal in areas subject to hunting or other disturbance.
The species is omnivorous. Its diet includes aquatic plants, seeds, grains, insects, worms, snails, crustaceans, other aquatic invertebrates and small fish. Feeding takes place in shallow or sheltered water, on wet ground and in nearby vegetation. The balance between plant and animal food varies with season, age and local availability.
White-winged Ducks are associated with forest nesting sites and are considered cavity nesters, although nesting may also occur in concealed locations where suitable cavities are unavailable. Breeding timing varies geographically, but in parts of India, Thailand and Myanmar it is linked to the beginning of the wet season. Females incubate the eggs, while the male commonly remains near the nest and accompanies the female during feeding movements. Pairs can be territorial, particularly during the breeding season.
Research, field surveys and monitoring are important because the species is difficult to observe and its remaining populations are widely separated. Conservation breeding programmes also contribute to research, although captive populations face challenges including avian tuberculosis and limited genetic diversity.
Identification Tips
Look for the following combination of features:
- A large, heavy-bodied duck associated with forested freshwater wetlands.
- A pale, black-speckled head and upper neck contrasting with a dark, glossy body.
- Chestnut-brown lower parts in many mainland adults, although plumage varies.
- Strong white wing patches that are especially obvious in flight.
- Orange-yellow legs and an orange to yellowish bill marked with black.
- A secretive, crepuscular or nocturnal habit, often revealed by calls or flight between forest and feeding wetlands.
The White-winged Duck should not be confused with the Muscovy Duck merely because both are large and dark-bodied. The White-winged Duck has a more distinctive pale, mottled head and prominent white wing patches, and it is currently placed in the separate genus Asarcornis. Juveniles also retain white wing patches, whereas young Muscovy Ducks do not show the same combination of features.
Conservation Status
The White-winged Duck is listed as Critically Endangered on the IUCN Red List, following the 2024 assessment. Recent assessments indicate that only a few hundred mature individuals may remain in the wild, with estimates of approximately 150–450 mature individuals cited in current conservation literature. The population is small, severely fragmented and continuing to decline.
The principal threats are the destruction and degradation of swamp forest and freshwater wetlands, forest fragmentation, disturbance, hunting, trapping and the collection of eggs or young in some areas. Pollution, changes in water flow, drying wetlands and climate-related habitat changes may add further pressure. Local extinction has already occurred in parts of the former range.
Important conservation measures include:
- Protecting remaining forested wetlands and safeguarding known breeding sites.
- Preventing hunting, trapping and the collection of eggs or ducklings.
- Maintaining shaded streams, ponds, swamps and other slow-moving freshwater habitats.
- Monitoring small and isolated populations through coordinated field surveys.
- Working with local communities to reduce disturbance and support wetland protection.
- Maintaining carefully managed conservation-breeding populations while addressing avian tuberculosis and genetic diversity.
- Using research, education and habitat restoration to improve long-term recovery prospects.
Frequently Asked Questions
Where does the White-winged Duck live?
It inhabits mature swamp forest, shaded streams, quiet ponds, oxbow lakes and other freshwater wetlands in parts of north-eastern India, Myanmar, Thailand and Indonesia. Much of its former range has been lost or severely fragmented.
Is the White-winged Duck endangered?
Yes. The species is currently listed as Critically Endangered on the IUCN Red List. Its remaining populations are small, fragmented and threatened by habitat loss, hunting and disturbance.
What does the White-winged Duck eat?
It is omnivorous and eats aquatic plants, seeds, grains, insects, worms, snails, crustaceans, other aquatic invertebrates and small fish. The importance of each food type varies between sites and seasons.
Is the White-winged Duck migratory?
It is generally regarded as resident rather than a regular long-distance migrant. Individuals may make local movements between forest roosts, breeding areas and feeding wetlands.
How can the White-winged Duck be identified?
It is a large, secretive duck with a pale black-speckled head, a dark glossy body, orange-yellow legs and conspicuous white wing patches. The wing patches are particularly easy to see when the bird flies.
Why is the White-winged Duck important to conservation?
Protecting this species also protects mature swamp forests, shaded freshwater systems and other wetlands that support many plants and animals. Its decline is an indicator of the wider loss and degradation of South and Southeast Asian wetland habitats.
References
- BirdLife International. 2024. Asarcornis scutulata. The IUCN Red List of Threatened Species 2024: e.T22680064A244637841. IUCN Red List of Threatened Species. https://doi.org/10.2305/IUCN.UK.2024-2.RLTS.T22680064A244637841.en. Accessed 8 September 2026.
- BirdLife International. 2026. White-winged Duck Asarcornis scutulata species factsheet. BirdLife DataZone. https://datazone.birdlife.org/species/factsheet/white-winged-duck-asarcornis-scutulata. Accessed 8 September 2026.
- Petry, A., & Davoigneau, L. 2025. EAZA Best Practice Guidelines: White-winged Duck (Asarcornis scutulata). Edition 1.1. European Association of Zoos and Aquaria, Waterfowl TAG. https://doi.org/10.61024/BPGWhitewingedduckEN.
- Foote, D. J., et al. 2026. Tuberculosis susceptibility and inbreeding depression hinder ex situ conservation in a critically endangered rainforest bird. Molecular Ecology Resources. https://pmc.ncbi.nlm.nih.gov/articles/PMC13291423/. Accessed 8 September 2026.
- Gill, F., Donsker, D., & Rasmussen, P. (eds). 2026. IOC World Bird List, version 15.2. International Ornithologists’ Union. https://www.worldbirdnames.org/. Accessed 8 September 2026.
- Green, A. J. 1993. The biology of the White-winged Duck Cairina scutulata. Forktail, 8, 65–82.
- Green, A. J., Carroll, J. P., & Maddock, M. 2005. White-winged Wood Duck Asarcornis scutulata: food and feeding behaviour. In J. Kear (ed.), Ducks, Geese and Swans, Volume 2, pp. 532–533. Oxford University Press.
- Green, A. J., Hughes, B., & Callaghan, D. 2005. White-winged Duck Cairina scutulata. In J. Kear (ed.), Ducks, Geese and Swans, Volume 2, pp. 455–459. Oxford University Press.
- Wildlife Trust of India. 2026. White-winged Duck recovery project in Assam and Arunachal Pradesh. https://www.wti.org.in/projects/recovering-white-winged-wood-duck-in-assam-arunachal-pradesh/. Accessed 8 September 2026.
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