林鸳鸯种

保护

19世纪末，由于栖息地丧失和人类滥捕滥杀（食用或使用其羽毛制造帽饰）的缘故，其数量大幅下降。《1918年候鸟保护法》实施之后种群数量才开始恢复。

The wood duck or Carolina duck (Aix sponsa) is a partially migratory species of perching duck found in North America. The male is one of the most colorful North American waterfowls.

Taxonomy

The wood duck was formally described in 1758 by the Swedish naturalist Carl Linnaeus in the tenth edition of his Systema Naturae under the binomial name Anas sponsa. Linnaeus based his account on the "summer duck" from Carolina that had been described and illustrated by the English naturalist Mark Catesby in the first volume of his The Natural History of Carolina, Florida and the Bahama Islands that was published between 1729 and 1731. Linnaeus specified the type locality as North America but this has been restricted to Carolina following Catesby. The wood duck is now placed together with the mandarin duck in the genus Aix that was introduced in 1828 by the German naturalist Friedrich Boie. The species is monotypic: no subspecies are recognised.

Description

The wood duck is a medium-sized perching duck. A typical adult is from 47 to 54 cm (19 to 21 in) in length with a wingspan of between 66 and 73 cm (26 and 29 in). The wood duck's weight ranges from 454–862 grams (16.0–30.4 oz). This is about three-quarters the length of an adult mallard. It shares its genus with the Asian mandarin duck (Aix galericulata).

The adult male has stunning multicolored iridescent plumage and red eyes, with a distinctive white flare down the neck. The female, less colorful, has a white eye-ring and a whitish throat. Both adults have crested heads. The speculum is iridescent blue-green with a white border on the trailing edge.

Distribution

The birds are year-round residents in parts of its southern range, but the northern populations migrate south for the winter. They overwinter in the southern United States near the Atlantic Coast. 75% of the wood ducks in the Pacific Flyway are non-migratory.

Due to their attractive plumage, they are also popular in waterfowl collections and as such are frequently recorded in Great Britain as escapees—populations have become temporarily established in Surrey in the past, but are not considered to be self-sustaining in the fashion of the closely related mandarin duck. Along with the mandarin duck, the wood duck is considered an invasive species in England and Wales, and it is illegal to release them into the wild.

Behavior

Reproduction

Their breeding habitat is wooded swamps, shallow lakes, marshes, ponds and creeks in the eastern United States, the west coast of the United States, some adjacent parts of southern Canada, and the west coast of Mexico. They get their name from being one of the only species of ducks who perch and nest in trees. In recent decades, the breeding range has expanded towards the Great Plains. Currently most breeding occurs in the Mississippi alluvial valley. They usually nest in cavities in trees close to water, although they will take advantage of nesting boxes in wetland locations. Other species may compete with them for nesting cavities, such as birds of prey, as well as mammals such as grey squirrels, and these animals may also occupy nest boxes meant for wood ducks.

Predation

Wood ducks are commonly eaten by great horned owls, American mink, raccoons, red foxes, gray foxes, American alligators, and black rat snakes.

Conservation

The population of the wood duck was in serious decline in the late 19th century as a result of severe habitat loss and market hunting for both meat and plumage for the ladies' hat market in Europe. By the beginning of the 20th century, wood ducks had become rare, almost disappearing in many areas. In response to the Migratory Bird Treaty, established in 1916, and enactment of the U.S. Migratory Bird Treaty Act of 1918, wood ducks finally began to repopulate. By enforcing existing hunting regulations and protecting woodland and marsh habitat, wood duck populations began to rebound starting in the 1920s. The erection of nesting boxes starting in the 1930s further assisted wood duck conservation. A synopsis of evidence from multiple studies performed by Williams et al.

In popular culture

In 2013, the Royal Canadian Mint created two coins to commemorate the wood duck. The two coins are each part of a three coin set to help promote Ducks Unlimited Canada as well as celebrate its 75th anniversary.