| Aix | |
|---|---|
 | |
| Malemandarin duck (A. galericulata), left, and malewood duck (A. sponsa), right | |
Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Aves |
| Order: | Anseriformes |
| Family: | Anatidae |
| Subfamily: | Anatinae |
| Genus: | Aix F. Boie, 1828 |
| Type species | |
| Aix sponsa | |
| Species | |
Aix is a birdgenus that contains twospecies ofducks: thewood duck (Aix sponsa), and themandarin duck (Aix galericulata).Aix is anAncient Greek word used byAristotle to refer to an unknown diving bird.[1]
The genus belongs to thefamilyAnatidae in the waterfowlorderAnseriformes. They were formerly placed in the "perching ducks", aparaphyletic group somewhat intermediate betweenshelducks anddabbling ducks, and it is not quite clear whether they should be placed in theAnatinae (dabbling duck) orTadorninae (shelduck)subfamily.[2][3]
| Common name | Scientific name and subspecies | Range | Size and ecology | IUCN status and estimated population |
|---|---|---|---|---|
| Wood duck
| Aix sponsa (Linnaeus, 1758) | North American species,[4] eastern half of theUnited States, and from southernCanada to northernMexico | Size: The wood duck has a mass of 500–700 grams (18–25 oz). It is 41–49 centimeters (16–19 in) in length, and has a wingspan of 73–75 cm (29–30 in). Males have red eyes and iridescent plumage. Both sexes have crested heads. Habitat: Diet: | LC |
| Mandarin duck
| Aix galericulata (Linnaeus, 1758) | Asian species occurring mainly inJapan andChina; introduced populations can be found in theUnited Kingdom,Western Europe and isolated areas of North America | Size: The Mandarin duck is 41–49 cm (16–19 in) long with a 65–75 cm (26–30 in) wingspan. It has an even more flamboyant plumage than the wood duck. The female Mandarins are less brightly colored than the males. Habitat: Diet: | LC |
Both speciesmigrate from the northern parts of their respective ranges to winter in the south of the range. They inhabit quiet wooded streams and ponds.
The two species are generally considered to be very attractive, particularly the multi-coloured drakes. The genus shows markedsexual dimorphism (differences between the sexes), with the females being smaller and less colorful.
Wood ducks will consume smallcrustaceans,insects, and plant matter. Mandarin ducks are mainly vegetarian.
Wood ducks are reproductively capable around the age of one year. They are monogamous for the season. Mating occurs between February and April, depending on latitude. Theclutch size is between 6 and 15, and the incubation period is about 30 days. The young are precocial. They venture from the cavity nest at one day old and are cared for by the mother for about 60 days. The young have a very high mortality rate. Wood ducks normally live 3 to 4 years.
Mandarin ducks are also monogamous. The courtship ritual, like the plumage, is rather showy. The female lays between 9 and 12 eggs in a cavity nest, then incubates them for about 30 days. Parental care by the mother is a little shorter in this species, lasting about 40 days.
Both species are affected by loss of habitat. As human development continues to expand, the woodland areas preferred by these ducks continues to shrink. As of 2016, both species had been evaluated for theRed List of theInternational Union for Conservation of Nature (IUCN), and given a "least concern" rating.[5][6]
