Blue Duck
Hymenolaimus malacorhynchos
Endemic to New Zealand. Uniformly slate-blue duck with chestnut spotting on the breast. Bill is pale pink with a black tip. Males larger than females, with more breast spotting and more prominent green iridescence on the head, neck, and back. Found on clear, fast-flowing mountain streams. The Maori name, whio, is derived from the male’s high-pitched, wheezy whistle. Female’s call is a low rasping growl, often in response to disturbance. Readily distinguished from Pacific Black Duck or Mallard by uniform coloration and, if on the water, prominent tail tilted upward and head held erect.
识别特征
The blue duck is 53 cm (21 in) long and varies in weight by sex. Females are smaller than males, weighing 680–870 g (24–31 oz), whereas the males weigh 820–970 grams (29–34 oz). The plumage is a dark slate-grey with a greenish sheen on the head, a chestnut-flecked breast. The outer secondaries are tipped with white and the inner ones have black margins. The plumage of the two sexes are mostly the same, although the female has slightly less chestnut in the chest. The pinkish-white bill has fleshy flaps of skin hanging from the sides of its tip. The beak is green at hatching and develops its final colour eight hours later .<p>The male's call is a high-pitched whistle. The female's call is a rattling growl or low-pitched grating notes.
分类信息
Captain James Cook saw the blue duck in Dusky Sound, South Island, New Zealand, on his second voyage to the south Pacific. In 1777 both Cook and the naturalist Georg Forster mentioned the blue duck in their separate accounts of the voyage. A specimen was described in 1785 by the English ornithologist John Latham in his A General Synopsis of Birds. Latham used the English name, the "soft-billed duck". When in 1789 the German naturalist Johann Friedrich Gmelin revised and expanded Carl Linnaeus's Systema Naturae he included the blue duck and placed it with all the other ducks in the genus Anas. He coined the binomial name Anas malacorhynchos and cited the earlier works. The blue duck is now the only species placed in the genus Hymenolaimus that was introduced specifically for the species by George Robert Gray in 1843. The genus name combines the Ancient Greek humēn, humenos meaning "skin" or "membrane" with laimos meaning "throat". The specific epithet malacorhynchos is also from Ancient Greek and combines malakos meaning "soft" with rhunkhos meaning "bill".<p>The species has no close relatives. Its taxonomic relationships with other waterfowl species remains uncertain; DNA analysis has placed it as a sister to the South American dabbling ducks (Anatini), but with no close relative. As of 2013, it was commonly listed as incertae sedis but likely within the Anatinae and allied to the Anatini. It was formerly thought to be related to the shelduck tribe.<p>It is commonly known in New Zealand English by its Māori name Whio, pronounced /ˈfiɔː/ FEE-oh, which is an onomatopoeic rendition of the males' call. Other names may be known by are Mountain Duck or Blue Mountain Duck.<p>Two subspecies are recognised:<p>Prior to 2022, the North Island and South Island whio were considered distinct but were not distinguished as subspecies; they were, however, treated as separate management units. However, the populations were defined as distinct subspecies by the International Ornithological Congress in 2022, based on strong genetic divergence and some plumage differences.
- 学名
- Hymenolaimus malacorhynchos
- 命名信息
- (Gmelin, JF, 1789)
- 目
- Anseriformes
- 科
- Unknown
- 属
- Hymenolaimus
分布与栖息地
- 迁徙
- Resident species
行为
This species is an endemic resident breeder in New Zealand, nesting in hollow logs, small caves and other sheltered spots. It is a rare duck, holding territories on fast flowing mountain rivers. It is a powerful swimmer even in strong currents, but is reluctant to fly. It is difficult to find, but not particularly wary when located.<p>The blue duck feeds almost entirely on aquatic invertebrate larvae. A study of blue ducks on the Manganuiateao River in the central North Island found the most common prey items were Chironomidae (midge) and cased caddisfly larvae, although cased caddisfly were less preferred and were only consumed so much because of their abundance. Hydrobiosidae (free-living caddisfly) and Aphrophila neozelandica (crane fly) larvae were also frequently eaten. Other prey included mayfly, Aoteapysche (net-building caddis) and stonefly larvae. The blue duck on occasion take berries and the fruits of shrubs.<p>Blue ducks nest between August and October, laying 4–9 creamy white eggs. The female incubates the eggs for 31 to 32 days and chicks can fly when about 70 days old.<p>Nesting and egg incubation of four to seven eggs is undertaken by the female while the male stands guard. Nests are shallow, twig, grass and down-lined scrapes in caves, under river-side vegetation or in log-jams, and are therefore very prone to spring floods. For this, and other reasons, their breeding success is extremely variable from one year to the next.
保护状况
- 种群趋势
- declining
照片
分布
鸟叫声
其他鸟类
Rain Quail
Coturnix coromandelica
Streaky, small football-shaped bird, most often seen in flight as it flushes from almost underfoot. Male unmistakable, with natty black-and-white face pattern and triangular black splotch on the chest that resembles spilled paint. Female very similar to Common and Japanese Quails, distinguished by range and by proximity to a male. Inhabits grassy, open areas such as farmland, meadows, and grasslands. Disperses after breeding, occasionally to higher elevations. Male’s song is an odd, songbird-like pair of repeated high squeaks.
Cabanis's Greenbul
Phyllastrephus cabanisi
Typically dull mid-sized greenbul with a long bill and tail. There is geographical variation, with the western birds more yellowish below, and the eastern birds more whitish. Usually shows a distinctive pale eye-ring. Found in the thick undergrowth and mid-story of forest at middle and high elevations, usually in small groups. The call starts with slow and chatty notes, then accelerates into a grating, up-and-down series. Somewhat similar to Gray-olive Greenbul, but larger, with a darker bill and legs and usually some yellowish tones on the underparts. Similar to brownbuls, but more olive-green on the back and yellowish below.
Speckle-breasted Woodpecker
Dendropicos poecilolaemus
Small, rather pale greenish woodpecker. The underparts are mostly plain yellowish, with fine spotting on the breast. The crown is black and red in males and all black in females. Found in lush woodland and farmland and along forest edge. Fairly similar to other small, green-backed woodpeckers, but easily identified by the pattern of its underparts.
开始您的观鸟之旅
在户外识别鸟类，并在下一次观察时随手查阅鸟类图鉴。