Koloa Maoli or Hawaiian Duck

[Tom Phillips*]

Koloa Maoli or Hawaiian Duck
Anas wyvilliana

SPECIES INFORMATION: Koloa breed year round, with peak breading season between January and May. On Kaua‘i, pair bonds are formed between November and May, with pairs usually nesting in montane areas (though some have been found in lowland wetlands as well). Nests are usually on the ground near water. Few nests are found in areas disturbed by human
populations as well as those of cats, dogs, or mongoose. Clutch sizes range from 2-10 eggs.

Koloa are usually found alone or in pairs, though they may gather in larger numbers where rich food sources are available. They are opportunistic feeders and food can include snails, dragonfly larvae, earthworms, grass seeds, rice, green algae, and seeds/leaf parts of wetland plants. Feeding usually occurs in wetlands and streams 1-5 inches deep.

ABUNDANCE: Estimated population is 2,500.

LOCATION AND CONDITION OF KEY HABITAT: Historically, koloa used a wide variety of natural wetland habitats for nesting and feeding (e.g. freshwater marshes, flooded grasslands, coastal ponds, streams, montane pools, and forest swamplands from elevations ranging from sea level up to 9,900 feet). Montane systems are critical with artificial wetlands (such as taro, lotus, shrimp, and fish ponds) and man-made ponds supplementing existing
habitat and provide important feeding habitat. Additionally, stream systems are also utilized as well as irrigation ditches, flooded ephemeral fields, reservoirs, and mouths of larger streams.

Inter-island movement also occurs between the Kaua‘i and Ni‘ihau populations during winter. Koloa may also move seasonally from lowland wetlands to more secluded habitats in the summer. Some koloa habitats are located in National Wildlife Refuges as well as State sanctuaries (see distribution) and can be considered stable. Those areas outside of such protection and management, particularly those facing urban development or industry decline
(such as plantations and aquaculture industries), can be considered critical.

Examples include:
Playa Lakes on Niihau, Opaekaa Marsh, Mana and Lumahai Wetlands on Kaua‘i, Amorient prawn farms, Laie Wetlands, Uko, Punahoolapa, and Waihee Marshes, Waialua lotus fields, and Waipio Peninsula Ponds on O‘ahu, Paialoa and Ooia Playa fishponds on Moloka‘i, and Opaeula, Montane Stock, and Waiakea -Loko Waka Ponds on the island of Hawai‘i.

DISTRIBUTION:
Historically found in all the main Hawaiian Islands (except La-na‘i and Ka-ho‘olawe), Koloa were fairly common in natural and farmed wetland habitats. Currently, wild populations are found on Kaua‘i (Hanalei National Wildlife
Refuge, montane streams), Ni‘ihau, with restored populations on O‘ahu (Kawainui, Hamakua, Heeia Marshes, James Campbell National Wildlife Refuge, Punahoolapa, Haleiwa, Pearl Harbor, and Lualualei Valley), Maui (Kahului,
Kanaha and Kealia Ponds), and the island of Hawai‘i (Kohala Mountains, Pololu, Waimanu and Waipio Valleys, and Mauna Kea).

DRAFT: Hawaiian Duck, January 26, 2005
THREATS: Historically, predation of eggs and chicks by rats, mongoose, cats, introduced fish and birds, hunting, and habitat destruction through development and introduced ungulates led to steep declines in the early 1900s. In addition to facing shared threats from loss of wetland habitat, introduced predators, altered hydrology, invasion of habitats from alien plants, avian diseases, and environmental contaminants, currently the primary threat to koloa is hybridization with feral domestic-type mallards. Damage of watershed stream systems by pigs, goats, and other feral ungulates also pose direct threats. Additionally, predation by dogs poses
a particular threat to Koloa on O‘ahu.

CONSERVATION ACTIONS: The goals of conservation actions are to not only protect current populations, but to also establish further populations to reduce the risk of extinction. Past actions have included efforts to restore wetland habitats, establishment of refuges and sanctuaries, captive propagation and release of populations, institution of a hunting ban,
restrictions on the importation of mallards, population monitoring, and research projects. In addition to common state-wide and island conservation actions, specific actions include:

-- Continue restoration of vital habitat for populations;
-- Eliminate hybridization of domestic-type mallard with koloa populations;
-- Conduct education and awareness programs, particularly to address issues of predation by dogs and cats;
-- Increase adaptive management of seasonal and permanent wetlands.

MONITORING:
§ Continue surveys of population and distribution in known and likely habitats;
§ Continue to track hybridized populations with the goal of removing hybrids and possibilities for future hybridization;
§ Monitor duck response to issues of modified watershed, alien plants, and other invasives.

RESEARCH PRIORITIES:
§ Conduct research on how to control and eliminate hybridization of mallards and koloa;
§ Conduct research to better define limiting factors, determine recovery objectives, and improve management techniques;
§ Better understand ecology of life history, particularly breeding, dispersal , seasonal movements, foraging ecology and role of montane-stream habitats;
§ Better understand the role of disease in limiting populations, particularly on Kaua‘i.

References:
DRAFT: Hawaiian Duck, January 26, 2005
U.S. Fish and Wildlife Service. 1999. Draft Revised Recovery Plan for Hawaiian Waterbirds, Second Revision. U.S. Fish and Wildlife Service, Portland, OR. 107 pp.

IUCN Red List of Threatened Species. http://www.redlist.org/search/details.php?species=1236
Engilis, Andrew Jr., Kimberly J. Uyehara, and Jon G. Giffin. 2002. Hawaiian Duck (Anas wyvilliana). In the Birds of North America, No. 694 (A. Poole and F. Gill, eds). The Academy of Natural Sciences, Philadelphia, PA and The American Ornithologists’ Union, Washington, D.C.

[AvianQuest]

Interesting duck...



They are considered to be an "island" subspecies of the Mallard.

This is similar to other species like the Black Duck and the Mottled Duck which probably were originally Mallards that were isolated from the main population by glacier movements. Because they were separated from other duck species, the drakes lost their breeding colors in favor of better camo.

[Tom Phillips*]

I would like to do all I can to help the koloa recover and since:

"... currently the primary threat to koloa is hybridization with feral domestic-type mallards."

I am willing to volunteer to go to Hawaii and shoot those feral mallards. AQ, want to join me? Anyone else?

It will be a Scientific Expedition.

Tom*

[AvianQuest]

Just got my Mar-Apr DU Magazine today, and in the Greenwings Section on pages 62-63 there's photo's of the seven Mallard cousins...

1. American black duck
2. Pacific black duck
3. Spot-billed duck
4. Philippine duck
5. Mottled duck
6. Hawaiian duck
7. Laysan duck

[AvianQuest]

Originally Posted by Tom Phillips*

I am willing to volunteer to go to Hawaii and shoot those feral mallards. AQ, want to join me? Anyone else?

It will be a Scientific Expedition.

Tom*

I'd like to shoot a few rounds into the Brown-breasted Beach Thrashers as well...

[Tom Phillips*]

http://pubs.usgs.gov/fs/2007/3047/

U.S. Geological Survey
Fact Sheet 2007-3047
Version 1.0
Hawaiian Duck’s Future Threatened by Feral Mallards
By Kimberly J. Uyehara, Andrew Engilis, Jr., and Michelle Reynolds
2007

The greatest threat to the future of the Koloa maoli as a unique species is cross-breeding with the introduced Mallard duck (A. platyrhynchos). This photograph shows feral Mallards, including “barnyard ducks,” at Wailoa River State Park on Hawai‘i. (Photograph by K. Uyehara.)

Nearly 70 percent of Hawai‘i’s native bird species are found nowhere else on Earth, and many of these species are declining or in danger of extinction. Although the Hawaiian Islands were once home to a remarkable diversity of waterfowl, only three species remain—the Hawaiian Goose (Nēnē), Laysan Duck, and Hawaiian Duck (Koloa maoli)—all Federally endangered. The Koloa maoli is the only Hawaiian bird threatened by “genetic extinction” from hybridization with an invasive species—feral Mallard ducks. U.S. Geological Survey (USGS) biologists in Hawai‘i are working to find the causes of bird endangerment and ways to prevent extinction of the Koloa maoli and other threatened birds.

[Tom Phillips*]

Originally Posted by Tom Phillips*

http://pubs.usgs.gov/fs/2007/3047/

U.S. Geological Survey
Fact Sheet 2007-3047
Version 1.0
Hawaiian Duck’s Future Threatened by Feral Mallards
By Kimberly J. Uyehara, Andrew Engilis, Jr., and Michelle Reynolds
2007

The greatest threat to the future of the Koloa maoli as a unique species is cross-breeding with the introduced Mallard duck (A. platyrhynchos). This photograph shows feral Mallards, including “barnyard ducks,” at Wailoa River State Park on Hawai‘i. (Photograph by K. Uyehara.)

Nearly 70 percent of Hawai‘i’s native bird species are found nowhere else on Earth, and many of these species are declining or in danger of extinction. Although the Hawaiian Islands were once home to a remarkable diversity of waterfowl, only three species remain—the Hawaiian Goose (Nēnē), Laysan Duck, and Hawaiian Duck (Koloa maoli)—all Federally endangered. The Koloa maoli is the only Hawaiian bird threatened by “genetic extinction” from hybridization with an invasive species—feral Mallard ducks. U.S. Geological Survey (USGS) biologists in Hawai‘i are working to find the causes of bird endangerment and ways to prevent extinction of the Koloa maoli and other threatened birds.

Kimberly, Andrew, Michelle, and the USGS;

I've got much of the solution. Let me shoot the mallards, and we'll enhance the rest of the habitat for the Koloa. They breed year-round. It's a quick recovery.

Tom Phillips*