Stiff-tailed duck

Stiff-tailed duck Temporal range: Early Miocene to present
Male white-headed duck, Oxyura leucocephala
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Aves
Order:	Anseriformes
Family:	Anatidae
Tribe:	Oxyurini
Genus:	Oxyura Bonaparte, 1828
Species
Oxyura australis Oxyura jamaicensis Oxyura leucocephala Oxyura maccoa Oxyura vittata
Key:   Range of Oxyura vittata.   Range of Oxyura jamaicensis.   Range of Oxyura maccoa.   Range of Oxyura leucocephala.   Range of Oxyura australis.

The stiff-tailed ducks, Oxyura, are part of the Oxyurini tribe of ducks. The genus name is derived from Ancient Greek oxus, "sharp", and oura, "tail".

All have, as their name implies, long, stiff tail feathers, which are erected when the bird is resting. All have relatively large, swollen bills. These are freshwater diving ducks. Their legs are set far back, which makes them awkward on land, so they rarely leave the water.

Their unusual displays involve drumming noises from inflatable throat sacs, head throwing, and erecting short crests. Plumage sequences are complicated, and aging difficult. Plumage is vital for survival because of this animals tendency to spend time in the water.

The six extant members of this genus in summation are distributed widely throughout North America, South America, Australia, Asia, and much of Africa.

Species

Image	Scientific name	Common Name	Distribution
	O. australis	Blue-billed duck	Australia
	O. jamaicensis	Ruddy duck	North and South America
	O. ferruginea	Andean duck	Andes Mountains of South America
	O. leucocephala	White-headed duck	Spain, North Africa, and western and central Asia
	O. maccoa	Maccoa duck	eastern Africa from Sudan and Ethiopia to Tanzania and west to eastern Zaire, and southern Africa from Zimbabwe to Cape Province, South Africa
	O. vittata	Lake duck	central Chile, Argentina and southern Uruguay

• †New Zealand stiff-tailed duck, O. vantetsi

A fossil species from the Late Pliocene or Early Pleistocene of Jalisco (Mexico) was described as Oxyura zapatanima. It resembled a small ruddy duck or, even more, an Argentine blue-bill. A larger Middle Pleistocene fossil form from the southwestern United States was described as Oxyura bessomi; it was probably quite close to the ruddy duck.

"Oxyura" doksana from the Early Miocene of Dolnice (Czech Republic) cannot be assigned to any anatine subfamily with certainty.

Further reading

• Worthy, Trevor H.; Tennyson, A.J.D.; Jones, C.; McNamara, J.A. & Douglas, B.J. (2007): Miocene waterfowl and other birds from central Otago, New Zealand. J. Syst. Palaeontol. 5(1): 1-39. doi:10.1017/S1477201906001957 (HTML abstract)