The Hawaiian Duck (Anas wyvilliana)


koloa.jpgSpecies: Duck
Family: Anatidae
Also known as the Koloa, the Hawaiian Duck is a small is generally mottled brown and has a green to blue speculumn with white borders. Males are grow to be between 19-20 inches and females grow to be between 16-17 inches. Both males and females have orange legs and feet. They consume snails, earthworms, dragonflies, algae and the leaf parts and seed of a variety of wetland plants. They are frequently seen feeding in taro fields. Some pairs nest year round, but the primary breeding season is from December to May. During the breeding season, pairs are often engaged in spectacular nuptial (courtship) flights. Two to ten eggs are laid in a well-concealed nest lined with down and breast feathers. Soon after hatching, the young can take to the water, but cannot fly for nine weeks.

Habitat & Species Threats
The former range of the Hawaiian Duck included all of the main Hawaiian islands except the island of Lānaʻi. Now the Hawaiian Duck only exists on the island of Kauaʻi.

Threats to the koloa maoli include feral cats, rats, and Small Asian Mongooses, which eat the eggs and young.
Interbreeding with feral mallards is also a major problem, as the hybrids seem to be less well-adapted to the local ecosystem but still rather common due to the high numbers of feral mallards. Several attempted reintroductions have already failed due to the hybrid ducks produced in captivity faring badly in the wild.

The Problem
The decline of the Hawaiian Duck is directly related to the destruction of key wetland habitats in the Hawaiian Islands, particularly Waikïkï, Ka‘elepulu, Köloa Swamp, and Kawai nui marshes on O‘ahu and the Mana wetlands on Kaua‘i. On Hawai‘i, Maui, and Moloka‘i, this species was never abundant in historic times, owing to limited habitat. In addition to habitat loss, predation from introduced mammals dealt a severe blow to the species. Sport hunting continued well into the first third of the twentieth century and has been mentioned as a factor in the species’ decline.

State and Federal efforts in protecting wetlands, enforcing strict hunting laws, educating, and working with private organizations and landowners play an important role in ensuring the livelihood of the koloa and many other waterbirds.

The koloa was listed as an endangered species in 1967 under the Federal Endangered Species Act. The Hawaiian Waterbirds Recovery Plan was completed in 1978, revised in 1985, and is currently being revised and updated again.

"Hawaiian Duck - Pacific Islands Fish and Wildlife Office." U.S. Fish and Wildlife Service Home. Web. 05 Jan. 2011.
"Hawaiian Duck Aka Koloa: Species Information and Photos." AvianWeb: Home Page. Web. 05 Jan. 2011.
"Hawaiian Duck." Wikipedia, the Free Encyclopedia. Web. 05 Jan. 2011.