Aix

Superregnum: Eukaryota
Regnum: Animalia
Subregnum: Eumetazoa
Cladus: Bilateria
Cladus: Nephrozoa
Superphylum: Deuterostomia
Phylum: Chordata
Subphylum: Vertebrata
Infraphylum: Gnathostomata
Megaclassis: Osteichthyes
Superclassis: Sarcopterygii
Superclassis: Tetrapoda
Cladus: Reptiliomorpha
Cladus: Amniota
Classis: Reptilia
Cladus: Eureptilia
Cladus: Romeriida
Subclassis: Diapsida
Cladus: Sauria
Infraclassis: Archosauromorpha
Cladus: Crurotarsi
Divisio: Archosauria
Cladus: Avemetatarsalia
Cladus: Ornithodira
Subtaxon: Dinosauromorpha
Cladus: Dinosauriformes
Cladus: Dracohors
Cladus: Dinosauria
Ordo: Saurischia
Cladus: Eusaurischia
Cladus: Theropoda
Cladus: Neotheropoda
Cladus: Averostra
Cladus: Tetanurae
Cladus: Avetheropoda
Cladus: Coelurosauria
Cladus: Tyrannoraptora
Cladus: Maniraptoromorpha
Cladus: Maniraptoriformes
Cladus: Maniraptora
Cladus: Pennaraptora
Cladus: Paraves
Cladus: Eumaniraptora
Cladus: Avialae
Infraclassis: Aves
Cladus: Euavialae
Cladus: Avebrevicauda
Cladus: Pygostylia
Cladus: Ornithothoraces
Cladus: Euornithes
Cladus: Ornithuromorpha
Cladus: Ornithurae
Cladus: Carinatae
Parvclassis: Neornithes
Cohors: Neognathae
Cladus: Pangalloanserae
Cladus: Galloanseres
Ordo: Anseriformes

Familia: Anatidae
Subfamilia: Anatinae
Genus: Aix
Species: A. galericulata – A. sponsa – †A. praeclara
Name

Aix Boie, 1828: 329

Type species: Anas sponsa Linnaeus, 1758 [=Aix sponsa]
References
Primary references

Boie, F. 1828. Bemerkungen über mehrere neue Vogelgattungen. Isis, oder Encyclopädische Zeitung von Oken 21 col. 312–329. BHL Reference page. col. 329

Vernacular names
български: Горски патици
suomi: Mandariinisorsat
日本語: オシドリ属
한국어: 원앙속
русский: Мандаринки
中文: 鸳鸯属

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Aix is a genus that contains two species of ducks: the Wood Duck (Aix sponsa), and the Mandarin Duck (Aix galericulata).

The genus belongs to the family Anatidae in the waterfowl order Anseriformes. They were formerly placed in the "perching ducks", a paraphyletic group somewhat intermediate between shelducks and dabbling ducks, and it is not quite clear whether they should be placed in the Anatinae (dabbling duck) or Tadorninae (shelduck) subfamily.[1][2]

The two species are generally considered to be very attractive, particularly the multi-coloured drakes. Wood Ducks are a North American species,[3] occurring mainly in the eastern half of the United States, and from southern Canada to northern Mexico. Mandarin Ducks are an Asian species mainly in Japan and China, but there is an important feral population in the United Kingdom. Both species migrate from the northern parts of their respective ranges to winter in the south of the range. They inhabit quiet wooded streams and ponds.

The genus shows marked sexual dimorphism (differences between the sexes), with the females being smaller and less colorful.

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.

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.
Mandarin Duck (Aix galericulata)

Wood Ducks will consume small crustaceans, 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. The clutch 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 threatened by loss of habitat. As human development continues to expand, the woodland areas preferred by these ducks continues to shrink. The Mandarin Ducks may number less than 20,000.

References

1. ^ Johnson, Kevin P. & Sorenson, Michael D. (1999). "Phylogeny and biogeography of dabbling ducks (genus Anas): a comparison of molecular and morphological evidence" (PDF). Auk 116 (3): 792–805. http://elibrary.unm.edu/sora/Auk/v116n03/p0792-p0805.pdf. Retrieved September 2, 2008.
2. ^ Madge, Steve & Burn, Hilary (1987). Wildfowl : an identification guide to the ducks, geese and swans of the world. London: Christopher Helm. ISBN 0-7470-2201-1.
3. ^ "Wood Duck (Aix sponsa)". Northern Prairie Wildlife Research Center. United States Geological Survey. August 3, 2006. http://www.npwrc.usgs.gov/resource/1999/woodduck/wdrange.htm. Retrieved June 29, 2010.

* Harris, M. (1999): Animal Diversity Web: Aix galericulata . Accessed April 27, 2006.

* Pope, A. (2004): Animal Diversity Web: Aix sponsa. Accessed April 27, 2006.