The 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. Without plumage this duck would die of hypothermia because of an inability to regulate its body temperature. 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, Argentine Blue-bill. A larger Middle Pleistocene fossil form from the southwestern USA was described as Oxyura bessomi; it was probably quite close to the Ruddy Duck.
Listen to the sound of White-headed Duck
Copyright remark: Most sounds derived from xeno-canto
|wingspan min.:||64||cm||wingspan max.:||68||cm|
|size min.:||43||cm||size max.:||48||cm|
|incubation min.:||25||days||incubation max.:||26||days|
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Females lay 4-9 eggs, more usually 5 or 6, at 1.5 day intervals, and may relay if the first clutch is removed. Relative to body mass, lays the largest egg of any waterfowl, and total clutch mass may approach 100% of a female’s non-breeding body weight. Incubation begins from April to June in southern Europe, and up to a month later further north. Eggs hatch after 22-24 days in the wild. Only one brood is reared per year. Little information on hatching or nesting success. Brood size at hatching 3-7 ducklings, usually 5-6. The fledging period is 8-10 weeks, somewhat longer than most ducks. Females can breed first at one year old although the proportion doing so is unknown. It is one of the few water birds that moult twice a year, during breeding season and winter, being unable to fly during these periods.
many other aquatic plants. The availability of chironomid larvae is a key feature in habitat selection. Wintering birds on Caspian Sea contained snails Hydrobia, red seaweed Polysiphonia, and stonewort Chara, and seeds of Ruppia maritima. Females from central Kazakhstan, in July, contained seeds of Potamogeton and Najas, and waterboatmen Corixa
and Micronecta. Young caught at same time had only insects.
Video White-headed Duck
The species is Palearctic, with a fragmented breeding distribution extending east from Spain and Morocco in western Europe to western China and western Mongolia, and north from Iran to southern Russia. Divisions between biogeographical populations are
poorly understood (Scott & Rose 1996), but four major populations are thought to remain: a migratory central Asian population
breeding mainly in northern Kazakhstan and southern Russia and wintering in western Asia, the Middle East and in eastern
Europe as far west as Greece; a small and declining migratory east Asian population, wintering in Pakistan and perhaps
originating from southern Russia and Mongolia; a population resident in Spain, the Spanish population has increased from 22 birds in 1977 to around 2,500 wintering birds today; and another resident in North Africa (Tunisia and north-east Algeria).
Most of the population is concentrated in only four countries (Mongolia, Kazakhstan, Russian Federation, and Spain). The most important wintering countries differ from year-to-year, presumably depending on weather conditions. In recent years, ten
countries have held over 1,000 birds (Azerbaijan, Bulgaria, Greece, Islamic Republic of Iran, Israel, Kazakhstan, Russian
Federation, Spain, Turkey, and Uzbekistan. Seven countries hold significant numbers of White-headed Ducks
throughout the year (Algeria, Islamic Republic of Iran, Russian Federation, Spain, Tunisia, Turkey, and Uzbekistan). Since a few years the Spanish population is threatened by hybridisation with the Ruddy Duck, Oxyura jamaicensis, an introduced species from America. The other main threats are over hunting and habitat destrution.
The western population is resident, numbering about 1,000 birds breeding mainly in Spain but also in Algeria and Tunisia. The eastern population is larger and migratory. White-headed Ducks breed mainly in Turkey, where the biggest eastern population is located (200-300 pairs), while fewer breed in Russia, Iran and occasionally in Romania.
Moult movements are poorly understood, but large flocks of moulting individuals gather on certain sites (e.g. the Sudochie wetlands in Uzbekistan, and Lake Tengiz in Kazakhstan). Departure from breeding localities begins in late August and is
completed by mid-October. In Central Kazakhstan, largest numbers occur in September, but birds leave the region completely by mid-October. In Uzbekistan, major passage through the Amu Darya delta in October. In Pakistan, birds first appear in October and leave by the end of March. It is currently unknown whether there is interchange between the Spanish and North African populations. However, the recent increase in the number of White-headed Ducks in Morocco suggests that interchange does occur. Emigration of birds from Algeria or Tunisia was suggested as a possible explanation for the peak count of 4,489
birds in Spain in September 2002. However, as over 1,000 ducklings were hatched at El Hondo that year, it seems equally likely that these numbers could be explained by a bumper breeding year.
Oxyura leucocephala, in the face of hybridization with the North
American ruddy duck, Oxyura jamaicensis: results of a control trial
for the Conservation of the