Even wildlife biologists have a tough time telling the difference between the endangered koloa maoli (Hawaiian duck) and the common mallard. Cross-breeding or hybridization between the two species is the primary reason the endemic koloa is endangered.
To address the koloa’s future, the state Department of Land and Natural Resources is collaborating with the U.S. Fish and Wildlife Service and the University of Hawaii Pacific Studies Cooperative Unit on The Koloa Project. The project attempts to provide steps that will ensure its ultimate survival as one of three remaining native waterfowl species in Hawaii (the others being the Hawaiian nene or goose, and Laysan duck).
The koloa is a small duck, similar in appearance to the mallard but more secretive and behaving differently. Present in the Hawaiian Islands for at least 100,000 years, the koloa is found from sea level to as high as 10,000 feet. Cross-breeding with mallards began sometime in the late 1800s when the more common mallard was imported to Hawaii for ornamental ponds, hunting and farming. The FWS has recommended removing feral mallard ducks as a critical step toward saving the Koloa from extinction.
“The problem becomes distinguishing between koloa, feral mallards and hybrids in the field,” said Stephen Turnbull, DLNR Division of Forestry and Wildlife koloa communications and outreach coordinator. “Though they look very similar to female mallards, with a trained eye you can detect some of their unique characteristics, and we’re working toward an identification key based upon genetic markers to further our conservation efforts.”
One component of DLNR’s program to save the koloa is research to better identify the extent of the duck’s range on individual islands and determine how many native ducks remain versus hybridized ones. It’s believed fewer than 3,000 true koloa remain in the wild.
“We do know, for example, that the degree of hybridization on Kauai is very low, and we suspect that there may be small remnant populations of koloa on the other main Hawaiian Islands,” said William Aila Jr., DLNR chairman. “The other component is to raise public awareness to a level similar or exceeding awareness of the Hawaiian nene. It is especially important to remind people who have ‘barnyard’ ducks not to release them into the wild. This is the biggest factor affecting the decline of the koloa.”
The mallard is on the state List of Restricted Animals for importation. It and all birds continue to be under a shipping embargo instituted in 2002 due to the threat of West Nile Virus. Despite these controls, mallards continue to reproduce and be sold in Hawaii.
However, FWS believes the combination of research and public education will give the koloa “a high potential of recovery.” Once feral mallards are removed, there is every chance the endemic Hawaiian duck will once again be a familiar sight throughout Hawaii.
Advertisements about the koloa will appear in newspapers statewide over the next year. In addition, DLNR is conducting an online survey to gauge public awareness of the koloa. Individuals may take the survey at surveymonkey.com/s/koloa or facebook.com/HawaiiDLNR. The first 200 people to complete the survey will receive a custom designed Koloa T-shirt.