Chiloe wigeon (Anas sibilatrix)
|Also known as:||Black and white wigeon, Chilean wigeon, Chiloé wigeon, South American wigeon, Southern wigeon|
|Size||Length: 43 - 54 cm (2) (3)|
Wingspan: 75 - 86 cm (3)
|Weight||828 - 939 g (2)|
Classified as Least Concern (LC) on the IUCN Red List (1).
Named after the island of Chiloé, off the coast of Chile (4), the Chiloe wigeon is a relatively compact duck with an attractively patterned black and white body, chestnut flanks, and a broad, iridescent green band extending from the eye to the back of the neck (3) (4) (5). The cheeks and front of the face are white to yellowish-white, while the lower belly and rump are whitish and the tail is brown to black. The beak is bluish-grey with a black tip, black nostrils and a black lower mandible, and the legs and feet are grey (3) (4) (5). Prominent white shoulders are visible in flight (4) (5). A paler, duller variant also sometimes occurs and appears much less patterned (3). The male and female Chiloe wigeon are similar in appearance, but the male has a slightly rounder, chunkier head shape and the female is duller overall, particularly on the head, which has a less bright green band and a less pure white face (2) (3) (4) (5). Juveniles resemble the adults, but are much duller, with brown mottling on the forewings, barring on the sides and much less iridescence on the head (2) (3) (4).
The Chiloe wigeon is described as a highly vocal bird, and its species name, sibilatrix, means ‘whistling’, in reference to the male’s loud, whistling call. The female, in contrast, gives loud honks or a low growl (3) (4).
The Chiloe wigeon is found in South America, from northern Argentina, Chile, Paraguay, Uruguay and the extreme southeast of Brazil, south to Tierra del Fuego. The southernmost populations migrate northwards in winter (2) (3) (4) (5). The Chiloe wigeon also occurs on the Falkland Islands (2) (3) (4) (6) and has sometimes been recorded on the sub-Antarctic islands of South Georgia and South Orkney (2) (4) (6).
Inhabits freshwater lakes, marshes, lagoons and slow-flowing rivers, typically surrounded by scattered trees as well as more open grassland and meadows (2) (3) (4) (5).
The Chiloe wigeon feeds primarily on plant material, including grasses, sedges, aquatic vegetation, seeds and the green parts of plants (2) (4). It has also been recorded feeding on worms, larvae and fish during the summer months (4). It often feeds by grazing on the shore (2) (4), but will also dabble, head-dip and upend in water to find food (2). The breeding season usually begins in August or September, and nesting typically occurs in single pairs or small, loose groups. The nest is built on the ground, hidden amongst grass or vegetation. The female alone incubates the 5 to 9 eggs, which hatch after around 24 to 26 days (2) (4). The ducklings, which are dark brown above and buffy below (2) (4), are cared for by both the male and female (4). In captivity, the Chiloe wigeon first breeds at a year old, and, unlike other wigeon, this species is believed to form long-term pair bonds (4).
The Chiloe wigeon has a large range and is fairly common in many areas (2) (4) (6), and as such is not currently considered at risk of extinction (6). The species does face some pressure from hunting and habitat loss (2) (3) (4), and has also been impacted by the introduction of the American mink (Neovison vison) (4) (7), but its population is not yet thought to have undergone a significant decline (2) (6).
There are currently no known specific conservation measures targeted at the Chiloe wigeon. However, it is listed on Appendix II of the Convention on Migratory Species (CMS), which aims to conserve migratory species throughout their range (8), and in the Falkland Islands this species has been protected from shooting since 1999 (4).
For more information on the conservation of waterfowl see:
Threatened Waterfowl Specialist Group:
To find out more about conservation in the Falkland Islands and other UK Overseas Territories, see:
UK Overseas Territories Conservation Forum:
RSPB: The UK Overseas Territories - The UK’s hidden natural treasures:
For more information on this and other bird species please see:
- BirdLife International:
This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:
- Incubate: to keep eggs warm so that development is possible.
- Larvae: stage in an animal’s lifecycle after it hatches from the egg. Larvae are typically very different in appearance to adults; they are able to feed and move around but usually are unable to reproduce.
- Mandible: in birds, the lower jaw and beak, but the term is also used to denote the two parts of the beak.
IUCN Red List (September, 2010)
- del Hoyo, J., Elliott, A. and Sargatal, J. (1992) Handbook of the Birds of the World. Volume 1: Ostrich to Ducks. Lynx Edicions, Barcelona.
- Ogilvie, M.A. and Young, S. (2002) Photographic Handbook: Wildfowl of the World. New Holland Publishers, London.
- Kear, J. (2005) Ducks, Geese and Swans. Volume 2: Species Accounts (Cairina to Mergus). Oxford University Press, Oxford.
- Blake, E.R. (1977) Manual of Neotropical Birds. Volume 1: Spheniscidae (Penguins) to Laridae (Gulls and Allies). University of Chicago Press, Chicago and London.
BirdLife International (September, 2010)
- Peris, S.J., Sanguinetti, J. and Pescador, M. (2009) Have Patagonian waterfowl been affected by the introduction of the American mink Mustela vison? Oryx, 43(4): 648-654.
Convention on the Conservation of Migratory Species of Wild Animals (September, 2010)