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Aix (genus)
Encyclopedia
Aix is a genus
that contains two species
of duck
s: 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 duck
s", a paraphyletic group somewhat intermediate between shelduck
s and dabbling ducks, and it is not quite clear whether they should be placed in the Anatinae
(dabbling duck) or Tadorninae
(shelduck) subfamily.
The two species are generally considered to be very attractive, particularly the multi-coloured drakes. Wood Ducks are a North America
n species, occurring mainly in the eastern half of the United States
, and from southern Canada
to northern Mexico
. Mandarin Ducks are an Asia
n 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 g (17.6–24.7 ). It is 41 centimetre in length, and has a wingspan of 73 centimetre. Males have red eyes and iridescent plumage. Both sexes have crested heads.
The Mandarin Duck is 41 centimetre long with a 65 centimetre wingspan. It has an even more flamboyant plumage than the Wood Duck. The female Mandarins are less brightly colored than the males.
Wood Ducks will consume small crustacean
s, insect
s, 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.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
that contains two species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of duck
Duck
Duck is the common name for a large number of species in the Anatidae family of birds, which also includes swans and geese. The ducks are divided among several subfamilies in the Anatidae family; they do not represent a monophyletic group but a form taxon, since swans and geese are not considered...
s: the Wood Duck
Wood Duck
The Wood Duck or Carolina Duck is a species of duck found in North America. It is one of the most colourful of North American waterfowl.-Description:...
(Aix sponsa), and the Mandarin Duck
Mandarin Duck
The Mandarin Duck , or just Mandarin, is a medium-sized perching duck, closely related to the North American Wood Duck. It is 41–49 cm long with a 65–75 cm wingspan.-Description:...
(Aix galericulata).
The genus belongs to the family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Anatidae
Anatidae
Anatidae is the biological family of birds that includes ducks, geese and swans. The family has a cosmopolitan distribution, occurring on all the world's continents except Antarctica and on most of the world's islands and island groups...
in the waterfowl order
Order (biology)
In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...
Anseriformes
Anseriformes
The order Anseriformes contains about 150 living species of birds in three extant families: the Anhimidae , Anseranatidae , and the Anatidae, which includes over 140 species of waterfowl, among them the ducks, geese, and swans.All species in the order are highly adapted for an aquatic existence at...
. They were formerly placed in the "perching duck
Perching duck
The perching ducks were previously treated as a small group of ducks in the duck, goose and swan family Anatidae, grouped together on the basis of their readiness to perch high in trees...
s", a paraphyletic group somewhat intermediate between shelduck
Shelduck
The shelducks, genus Tadorna, are a group of large birds in the Tadorninae subfamily of the Anatidae, the biological family that includes the ducks and most duck-like waterfowl such as the geese and swans....
s and dabbling ducks, and it is not quite clear whether they should be placed in the Anatinae
Anatinae
The Anatinae is a subfamily of the family Anatidae . Its surviving members are the dabbling ducks, which feed mainly at the surface rather than by diving...
(dabbling duck) or Tadorninae
Tadorninae
The Tadorninae is the shelduck-sheldgoose subfamily of the Anatidae, the biological family that includes the ducks and most duck-like waterfowl such as the geese and swans....
(shelduck) subfamily.
The two species are generally considered to be very attractive, particularly the multi-coloured drakes. Wood Ducks are a North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
n species, occurring mainly in the eastern half of the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
, and from southern Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
to northern Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
. Mandarin Ducks are an Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...
n species mainly in Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
and China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
, but there is an important feral population in the United Kingdom
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
. Both species migrate
Bird migration
Bird migration is the regular seasonal journey undertaken by many species of birds. Bird movements include those made in response to changes in food availability, habitat or weather. Sometimes, journeys are not termed "true migration" because they are irregular or in only one direction...
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
Sexual dimorphism
Sexual dimorphism is a phenotypic difference between males and females of the same species. Examples of such differences include differences in morphology, ornamentation, and behavior.-Examples:-Ornamentation / coloration:...
(differences between the sexes), with the females being smaller and less colorful.
The Wood Duck has a mass of 500–700 g (17.6–24.7 ). It is 41 centimetre in length, and has a wingspan of 73 centimetre. Males have red eyes and iridescent plumage. Both sexes have crested heads.
The Mandarin Duck is 41 centimetre long with a 65 centimetre wingspan. It has an even more flamboyant plumage than the Wood Duck. The female Mandarins are less brightly colored than the males.
Crustacean
Crustaceans form a very large group of arthropods, usually treated as a subphylum, which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill and barnacles. The 50,000 described species range in size from Stygotantulus stocki at , to the Japanese spider crab with a leg span...
s, insect
Insect
Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...
s, 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.