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.
Taxonomy
- Scientific name
- Anas wyvilliana
- Authority
- Sclater, PL, 1878
- Order
- Anseriformes
- Family
- Anatidae
- Genus
- Anas
Range and habitat
- Migration
- Resident species
Behavior
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.
Conservation
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.
- Population trend
- rising
Photos
Distribution
Bird Calls
Other Birds
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Jamaican Tody
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Small bird with thin pointed bill found in middle- to high-elevation rainforests in far northern Queensland. Greenish gray above, pale below, with faint streaks on chest, pale eye, and faint pale speckling on gray forecrown. Forages among leaves of forest canopy. Compare Brown Gerygone, which has darker eye and white tail tips.
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