| White-backed duck | |
|---|---|
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Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Aves |
| Order: | Anseriformes |
| Family: | Anatidae |
| Subfamily: | Dendrocygninae Livezey, 1986 |
| Genus: | Thalassornis Eyton, 1838 |
| Species: | T. leuconotus |
| Binomial name | |
| Thalassornis leuconotus Eyton, 1838 | |
| Subspecies | |
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Thewhite-backed duck (Thalassornis leuconotus) is awaterbird of the familyAnatidae. It is distinct from all other ducks, but most closely related to thewhistling ducks in the subfamilyDendrocygninae, though also showing some similarities to thestiff-tailed ducks in the subfamilyOxyurinae. It is the only member of the genusThalassornis.
Thesebirds are well adapted for diving. On occasions they have been observed to stay under water for up to half a minute. They search especially for the bulbs ofwaterlilies, but also seeds and leaves of waterlilies and other water plants and the young feed onlake flies larvae as well.[1] From danger, they also escape preferentially by diving; hence, the namesake white back is hardly visible in life.
White-backed ducks live in Africa, especially betweenSenegal andChad in the west,Ethiopia in the east, andSouth Africa in the south. Their habitat consists of lakes, ponds, swamps and marshes where they are well camouflaged against predators.
There are two subspecies,Thalassornis leuconotus leuconotus andThalassornis leuconotus insularis. The latter lives entirely onMadagascar and is considered endangered as a result of hunting, habitat loss and the introduction of competing exotic species.
The white-backed duck is one of the species to which theAgreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA) applies.
Woolaver and Nichols conducted a nesting survey of the Madagascar race in 2001 at Lake Antsamaka in western Madagascar. They found a total of 37, indicating the significance of this single site for the conservation of this insular subspecies.[2] Young, et al. (2006) suggested that an earlier population estimate of 2,500–5,000 total birds in Madagascar by Delany and Scott[3] may be too optimistic.[4] Its African population may be in the range of 10,000 to 25,000 birds.[5][6]
