North American naturalists have traditionally grouped the Wood Duck with the Mallard and other common pond ducks as "dabblers," or "dabbling ducks." They recognize these as distinct from "divers" or "diving ducks" such as the Canvasback, based on both physical and behavioural differences. The male Wood Duck has two vocalizations: a loud distressed whoo-eek and a finchlike jeee, with rising inflection. Evidently the Wood Duck originated in North America, as fossil remains have been found only in widely scattered locations in the eastern part of the continent. Its only close relative is the Mandarin Duck of eastern Asia. The Wood Duck is a distinctively North American species. By studying the wings of ducks taken by hunters, biologists can determine the ratio of young to adult ducks in the population and thereby measure waterfowl production. The white tips on the feathers along the trailing edge of the wing are usually teardrop-shaped in the female, but either straight or V-shaped in the male. Females show a few small feathers on the upper surface of the wing that are purplish and have the same lustre as oil on water.
In the Wood Duck, as in other ducks, the feathers of that year’s young are finer, more pointed and worn, and less colourful than those of adults.
In most cases it is possible to distinguish immature from mature ducks and to tell males from females by their wings alone. The Wood Duck is the only North American duck so marked. The outer vanes of these feathers look as if they have been sprayed with aluminum paint. The primary wing feathers, which are the 10 outermost flight feathers attached to the wing beyond the wrist, are dark in colour. The wings of Wood Ducks are highly characteristic. Both sexes usually show a downward pointing crest at the back of the head, and their long broad square tails are distinctive features in flight. A white eye-ring, light-coloured throat, and fine crest distinguish the female from both the male Wood Duck and females of other species. At close range, its iridescent plumage, red eyes, and black, red, and white bill are conspicuous. From a distance, the male Wood Duck on the water appears as a dark-bodied, dark-breasted, light-flanked duck with a striped crested head and a light-coloured throat. Wood Ducks are intermediate in size, between the Mallard and Blue-winged Teal on average, males weigh 680 g and females weigh 460 g. The female is less showy, although still beautiful and more colourful than other female ducks.
The male in its multi-coloured breeding plumage, worn from October through June, is unexcelled among ducks. Many naturalists and hunters consider the Wood Duck Aix sponsa to be the most beautiful duck in North America, if not the world.
0 kommentar(er)
