The Yellow-billed Teal (Anas flavirostris) is a South America

South America

South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...

n species 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...

. Like other teal

Teal

Teal may mean:* Teal , a medium greenish-blue color* Various ducks:** Baikal Teal, Anas formosa** Black Teal, Aythya novaeseelandiae** Blue-winged Teal, Anas discors** Brown Teal, Anas aucklandica** Campbell Teal Anas nesiotis...

s, it belongs to the diverse genus Anas

Anas

Anas is a genus of dabbling ducks. It includes mallards, wigeons, teals, pintails and shovelers in a number of subgenera. Some authorities prefer to elevate the subgenera to genus rank...

; more precisely it is one of the "true" teals of subgenus

Subgenus

In biology, a subgenus is a taxonomic rank directly below genus.In zoology, a subgeneric name can be used independently or included in a species name, in parentheses, placed between the generic name and the specific epithet: e.g. the Tiger Cowry of the Indo-Pacific, Cypraea tigris Linnaeus, which...

 Nettion. It occurs in Argentina

Argentina

Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...

, the Falkland Islands

Falkland Islands

The Falkland Islands are an archipelago in the South Atlantic Ocean, located about from the coast of mainland South America. The archipelago consists of East Falkland, West Falkland and 776 lesser islands. The capital, Stanley, is on East Falkland...

, Chile

Chile

Chile ,officially the Republic of Chile , is a country in South America occupying a long, narrow coastal strip between the Andes mountains to the east and the Pacific Ocean to the west. It borders Peru to the north, Bolivia to the northeast, Argentina to the east, and the Drake Passage in the far...

, Peru

Peru

Peru , officially the Republic of Peru , is a country in western South America. It is bordered on the north by Ecuador and Colombia, on the east by Brazil, on the southeast by Bolivia, on the south by Chile, and on the west by the Pacific Ocean....

, Bolivia

Bolivia

Bolivia officially known as Plurinational State of Bolivia , is a landlocked country in central South America. It is the poorest country in South America...

, Uruguay

Uruguay

Uruguay ,officially the Oriental Republic of Uruguay,sometimes the Eastern Republic of Uruguay; ) is a country in the southeastern part of South America. It is home to some 3.5 million people, of whom 1.8 million live in the capital Montevideo and its metropolitan area...

, and Brazil

Brazil

Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...

. It has also established itself in South Georgia, where it was first recorded breeding in 1971. It inhabits freshwater

Freshwater

Fresh water is naturally occurring water on the Earth's surface in ice sheets, ice caps, glaciers, bogs, ponds, lakes, rivers and streams, and underground as groundwater in aquifers and underground streams. Fresh water is generally characterized by having low concentrations of dissolved salts and...

 wetland

Wetland

A wetland is an area of land whose soil is saturated with water either permanently or seasonally. Wetlands are categorised by their characteristic vegetation, which is adapted to these unique soil conditions....

s, preferring palustrine

Palustrine

Palustrine comes from the Latin word palus or marsh. Wetlands within this category include inland marshes and swamps as well as bogs, fens, tundra and floodplains...

 habitat

Habitat

* Habitat , a place where a species lives and grows*Human habitat, a place where humans live, work or play** Space habitat, a space station intended as a permanent settlement...

 to river

River

A river is a natural watercourse, usually freshwater, flowing towards an ocean, a lake, a sea, or another river. In a few cases, a river simply flows into the ground or dries up completely before reaching another body of water. Small rivers may also be called by several other names, including...

s. Considering its wide range and local abundance, it is not considered threatened by the IUCN.

Taxonomy

Mitochondrial DNA sequence

DNA sequence

The sequence or primary structure of a nucleic acid is the composition of atoms that make up the nucleic acid and the chemical bonds that bond those atoms. Because nucleic acids, such as DNA and RNA, are unbranched polymers, this specification is equivalent to specifying the sequence of...

 data is most similar to that of the very different-looking Green-winged Teal

Green-winged Teal

The Green-winged Teal is a common and widespread duck that breeds in the northern areas of North America except on the Aleutian Islands. It was considered conspecific with the Common Teal The Green-winged Teal (Anas carolinensis) is a common and widespread duck that breeds in the northern areas of...

. Apart from the mystifying relationship with the red-and-green-headed teals, it altogether most resembles the Indian Ocean

Indian Ocean

The Indian Ocean is the third largest of the world's oceanic divisions, covering approximately 20% of the water on the Earth's surface. It is bounded on the north by the Indian Subcontinent and Arabian Peninsula ; on the west by eastern Africa; on the east by Indochina, the Sunda Islands, and...

 radiation of teals. But the Yellow-billed Teal's unicolored underside and namesake bill are unique, as is to be expected from a species that evolved half a world apart from Bernier's

Bernier's Teal

Bernier's Teal Anas bernieri is a duck species of the genus Anas. It is endemic to Madagascar, where it is found only along the west coast....

 or the Grey Teal

Grey Teal

The Grey Teal, Anas gracilis is a dabbling duck found in open wetlands in New Guinea, Australia, New Zealand, Vanuatu and Solomon Islands....

.

This species is also unique among its relatives in some aspects of its post-copulation behavior: After dismounting, the drakes stretch themselves up high and swim around and alongside the females.

Traditionally, there are 2 subspecies

Subspecies

Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...

:

• Sharp-winged Teal, Anas flavirostris oxyptera (Meyen
  Franz Meyen
  Franz Julius Ferdinand Meyen was a German physician and botanist.Meyen was born in Tilsit. In 1830 he wrote Phytotomie, the first review of plant anatomy...
  
  , 1834) – highlands of central Peru to northern Chile and Argentina.
• Chilean Teal, Anas flavirostris flavirostris (Vieillot, 1816) – southern South America as far north as southern Brazil and northern Argentina. Also in the Falkland Islands
  Falkland Islands
  The Falkland Islands are an archipelago in the South Atlantic Ocean, located about from the coast of mainland South America. The archipelago consists of East Falkland, West Falkland and 776 lesser islands. The capital, Stanley, is on East Falkland...
  
  .

Previously, this species and the Andean Teal

Andean Teal

The Andean Teal is a South American species of duck. Like other teals, it belongs to the diverse genus Anas; more precisely it is one of the "true" teals of subgenus Nettion. It restricted to the Andean highlands of Colombia, Venezuela, and Ecuador. It inhabits freshwater wetlands, preferring...

formed the superspecies Speckled Teal, but increasingly taxonomists consider the two species distinct.