Stiff-tailed duck

Stiff-tailed ducks Temporal range: Early Miocene to present
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Male white-headed duck, Oxyura leucocephala
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Aves
Subclass:	Neornithes
Infraclass:	Galloanserae
Order:	Anseriformes
Family:	Anatidae
Subfamily:	Oxyurinae
Genus:	Oxyura Bonaparte, 1828
Species
Oxyura australis Oxyura jamaicensis Oxyura leucocephala Oxyura maccoa Oxyura vittata
File:Oxyura distribution.svg
Key:   Range of Oxyura vittata.   Range of Oxyura jamaicensis.   Range of Oxyura maccoa.   Range of Oxyura leucocephala.   Range of Oxyura australis.

Stiff-tailed ducks are part of the Oxyurinae subfamily of ducks. All have, as their name implies, long, stiff tail feathers, which are erected when the bird is at rest. All have relatively large, swollen bills. These are freshwater diving ducks. Their legs are set far back, making 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

• Blue-billed duck, O. australis
• New Zealand stiff-tailed duck, O. vantetsi (prehistoric)
• Ruddy duck, O. jamaicensis
• White-headed duck, O. leucocephala
• Maccoa duck, O. maccoa
• Lake duck, O. vittata

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.

"Oxura" 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)