[order] ANSERIFORMES | [family] Anatidae | [latin] Oxyura jamaicensis | [authority] Gmelin, 1789 | [UK] Ruddy Duck | [FR] Erismature rousse | [DE] Schwarzkopf-Ruderente | [ES] Pato Malvasia de Cara Blanca | [NL] Rosse Sterkelstaart
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.
The Ruddy Duck known for holding their spiky tails up in the air. They have large, flat bills, small wings, and feet set far back on the body. The male Ruddy Duck is cinnamon in color overall with a black head, large, white cheek-patch, and bright blue bill. The male in non-breeding plumage has a mottled gray body and gray bill. The markings on the head are similar to those of breeding plumage. The female is mottled gray overall with black on the top of her head and a dark, horizontal line that bisects her white cheek. Her bill is gray. The juvenile is similar to the female, but the black on its face is less pronounced.
Ruddy Ducks are often found in tight flocks. They forage by diving under water and straining mud through their bills to find food. Like many small-winged ducks, Ruddy Ducks must get a running start across the water to become airborne.
Listen to the sound of Ruddy Duck
Copyright remark: Most sounds derived from xeno-canto
North America, Middle America : widespread
In winter, Ruddy Ducks inhabit shallow, protected, saltwater bays and estuaries along the coast or ice-free, inland lakes and ponds. Breeding habitat is freshwater marshes and ponds with marshy borders mixed with open water.
Pairs form after the birds have arrived on the breeding grounds. Nests are situated in dense marsh vegetation. The female builds a platform of grasses and cattails, lines it with down, and anchors it to emergent vegetation a few inches above the water. Many nests are concealed by vegetation pulled over the nest, which gives them a basket-shaped appearance. Sometimes the nest is built on top of an old muskrat house or bird’s nest. The female lays 5 to 10 eggs (usually 8), and commonly lays eggs in the nests of other Ruddy Ducks or another species. The female incubates the eggs for 22 to 26 days. Within a day after hatching, the young leave the nest and can swim and dive well. They are tended by the female, but feed themselves. They first fly at 42 to 49 days.
Seeds and tubers from aquatic vegetation are a main staple of the Ruddy Duck’s diet. Aquatic insect larvae are especially favored during the breeding season. Mollusks, crustaceans, and some small fish are also eaten.
This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). Despite the fact that the population trend appears to be decreasing, the decline is not believed to be sufficiently rapid to approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is very large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.
In Britain, escaped captive birds began breeding regularly Somerset 1960 and Stafford 1961; have now reached Scotland and Wales. As range has expanded, records in continental Europe have increased, with first observation 1965 in Sweden (now almost annual) and from 1970s-80s elsewhere. Recorded from Iceland (bred 1990, 1993, 1994), Ireland (breeding since 1973), France (bred Pas-de-Calais 1988), Belgium (first breeding record 1991), Netherlands (occasional breeding since 1977, uncertain whether population self-sustaining), Germany, Denmark, Norway, Finland, Switzerland, Spain females have bred with males White-headed Duck in Andalucia), Portugal (bred 1995), Italy, and since December 1992 in Morocco. Beyond west Palearctic, breeds from western North America south through West Indies and western South America to Tierra del Fuego.
British population mainly resident, but with regular, short, seasonal movements, deserting small breeding pools and meres to winter on some large reservoirs. Flocks develop September-December and disperse March-April. Increasing records in continental Europe (see Distribution) show that some birds wander further afield.
Migratory in North America, withdrawing from breeding range (except in California) to winter in Pacific, Atlantic and Gulf coastal states of USA and south into Mexico, Belize, and Guatemala.
Title Conservation of the globally threatened white-headed duck,
Oxyura leucocephala, in the face of hybridization with the North
American ruddy duck, Oxyura jamaicensis: results of a control trial
Author(s): Baz Hughes, Iain Henderson, Peter Robertson
Abstract: The North American ruddy duck, introduced into Eur..[more]..
Source: Acta Zoologica Sinica 52(Supplement): 576-578, 2006
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