Hawaiian Duck
Anas wyvilliana
A medium-sized duck, similar to female Mallard in appearance, but smaller and darker. Males lack the green head and curled black tail feathers of male Mallards. Both sexes have spotted tail feathers. The bill is dark greenish, with an orange tip in some females. Pure Hawaiian Ducks occur only on Kauai and montane streams and ponds on Hawaii Island. Most or all individuals on other islands are Mallard-Hawaiian Duck hybrids. Occurs in ponds, marshes, taro fields, and streams.
分类信息
- 学名
- Anas wyvilliana
- 命名信息
- Sclater, PL, 1878
- 目
- Anseriformes
- 科
- Anatidae
- 属
- Anas
分布与栖息地
- 迁徙
- Resident species
行为
The Hawaiian duck is a very wary bird, often found in pairs instead of large groups. The koloa is most prominently found residing in the tall, wetland grasses and streams near the Kohala volcano on the main island of Hawaiʻi. They are very secretive birds and do not associate with other animals.
保护状况
Wildlife refuges including Hanalei National Wildlife Refuge on Kaua'i are essential breeding areas for Hawaiian ducks. The species was reintroduced to O’ahu between 1958 and 1982. In 1989, twelve of these captured birds were released on the island of Maui. The species was also reestablished on the island of Hawai'i between 1976 and 1982 (U.S. Fish and Wildlife Service 2005). Throughout the 1980s, the importation of mallards to Hawai'i was limited in an effort to reduce hybridization with Hawaiian ducks. Other conservation efforts for the Hawaiian duck include the development of "techniques for the identification of hybrids", which in turn will result in "simultaneous genetic testing and morphological characterisation".<p>Hybridization is arguably one of the most serious but overlooked threats to the Hawaiian duck, specifically interbreeding between Hawaiian ducks and feral mallards. Since hybridization has been happening for an extended period of time, it is unlikely there are any pure individuals of the species left. "Determination of the population status of Hawaiian ducks and whether there are any pure Hawaiian ducks left on O`ahu will require simultaneous genetic testing and morphological characterization to develop reliable morphological criteria for distinguishing Hawaiian ducks, female mallards, and hybrids. Once such criteria are available they can be used to identify birds for removal in order to reduce interbreeding and introgression."<p>It has been shown that offspring between mallards and the Hawaiian duck produce fertile offspring. It has also been shown on Kauai that breeding Hawaiian duck/mallard crosses with Hawaiian ducks over time reduces the expression of the mallard genes showing promise to restoring the natural population. Efforts are underway to remove mallards from the islands in order to preserve the genetic diversity of the Hawaiian duck.
- 种群趋势
- rising
照片
分布
鸟叫声
其他鸟类
Great Swallow-tailed Swift
Panyptila sanctihieronymi
Large, spectacular swift, seen singly or in small groups (up to 10 birds). Favors drier mountain and foothill areas, often near cliffs, but ranges widely. Rarely associates directly with other swifts. Flight is fast and graceful with long sweeping glides and deep wingbeats. Long, forked, swallow tail is usually held closed in a point. Note the size, shape, and contrasting white throat set off by a black body and cap.
Opal-rumped Tanager
Tangara velia
Common tanager, found in a variety of forest habitats. Usually seen from below, in which case it is best identified by uniform dark underparts with rufous lower belly and undertail coverts, and active behavior. The shining white rump can be seen from most angles on perched birds, even when high overhead. Found in tall rainforest, shorter-stature forests on sandy soils, and in disturbed areas. Groups move rapidly through treetops, usually with other species of small tanagers, feeding on fruit. Calls are indistinct chips, often given in rapid series in flight.
Stephanie's Astrapia
Astrapia stephaniae
A long-tailed bird of montane forest canopy. Male has much longer tail with an iridescent green head and bib with a black chest band bordered with a thin gold stripe. Female is blackish with barring on the belly. Feeds on fruit and searches for insects on mossy branches and epiphytes. Similar to Ribbon-tailed Astrapia (with which it can hybridize), but female Stephanie’s lacks the iridescence on the head and the male’s tail is black rather than white. Voice, a rising, nasal “week!”.
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