Torrent duck

Torrent duck
	Female (left) and male Colombian torrent duck, Cañón del Río Anaime, Colombia
Conservation status
	; Least Concern(IUCN 3.1)
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Aves
Order:	Anseriformes
Family:	Anatidae
Genus:	Merganetta; Gould, 1842
Species:	M. armata
Binomial name
	Merganetta armata; Gould,1842
Subspecies
	M. a. colombiana(Des Murs,1845); Colombian torrent duck; M. a. leucogenis(Tschudi,1843); Peruvian torrent duck; M. a. armata(Gould, 1842); Chilean torrent duck; M. a. berlepschi(Hartert,1909) (disputed); M. a. garleppi(Berlepsch,1894) (disputed); M. a. turneri(Sclater&Salvin,1869) (disputed);

Thetorrent duck(Merganetta armata) is a member of theduck,gooseandswan family Anatidae.It is the only member of thegenusMerganetta.It is placed in the shelducksubfamily Tadorninaeafter the "perching duck"assemblage to which it was formerly assigned was dissolved because it turned out to beparaphyletic.^[2]

This 43–46-centimetre (17–18 in) longspeciesis a resident breeder in theAndesofSouth America,nesting in small waterside caves and other sheltered spots. Like theblue duck,it holds territories on fast flowing mountain rivers, usually above 1,500 metres (4,900 ft). It is a powerful swimmer and diver even in white water, but is reluctant to fly more than short distances. It is not particularly wary when located.

Male torrent ducks have a striking black and white head and neck pattern and a red bill. In flight they show dark wings with a greenspeculum.Females of all subspecies are somewhat smaller than the drakes; they have orange underparts and throat, with the head and upperparts grey and a yellower bill. Juveniles are pale grey above and whitish below.

The male's call is a shrill whistle, while the female's is a throatier whistle.

This is a declining species due to competition for itsinvertebratefood from introducedtrout,pollution, forest destruction, and damming of mountain rivers for hydroelectric schemes. TheChileanpopulation seems to be relatively stable, while the more northern ones are more seriously affected. However, the overall population is still large enough to warrant classification as a Species of Least Concern in theIUCN Redlist.

Subspecies

Thesubspeciestaxonomy can be confusing. Males of the southernnominate subspeciesM. a. armata,the Chilean torrent duck, have grey back and blackish underparts, with a chestnut belly. Males of the slightly smaller northern subspecies, the Colombian torrent duck,M. a. colombiana,are paler underneath, with streaked grey-brown underparts. Males of a third subspecies, the Peruvian torrent duck,M. a. leucogenis,are intermediate but very variable in plumage; some have entirely black underparts (turnerimorph). Only males of the Chilean torrent duck have a black 'teardrop' mark beneath the eye. The Peruvian torrent duck is sometimes split into 4 subspecies (leucogenis,turneri,garleppiandberlepschi), but these are more likely simply color variations, as they are not limited to distinct areas.