A draft plan that outlines steps needed to recover four species of endangered Hawaiian waterbirds was released today by the U.S. Fish and Wildlife Service for public review and comment. This plan, which updates earlier recovery plans issued in 1978 and 1985, provides detailed guidance for numerous public and private entities engaged in conservation of the Hawaiian duck or koloa maoli, Hawaiian coot or alae keokeo, Hawaiian common moorhen or alae ula, and Hawaiian stilt or aeo.
These four species, found only in Hawaii New, were once found in a variety of wetland habitats on all the main Hawaiian Islands except Lnai and Kahoolawe," said Patrick Leonard, field supervisor for the Fish and Wildlife Services Pacific Islands Fish and Wildlife Office. "Loss of wetland habitat is the primary cause for the species decline, but predation by introduced animals may now be the greatest threat to the coot, moorhen, and stilt."
Five broad recovery objectives are outlined in the draft plan:
- increase population numbers to suitable statewide numbers;
- establish multiple, self-sustaining breeding populations throughout each species historical range;
- establish and protect a network of both core and supporting wetlands that are managed as habitat suitable for waterbirds;
- eliminate or control the threats posed by introduced predators, avian diseases, and contaminants; and
- for the Hawaiian duck, remove the threat of hybridization with feral mallards.
Specific criteria necessary for either downlisting (changing from endangered to threatened) or delisting (removing from the list of threatened and endangered species) each of the four waterbird species are identified under these objectives.
Throughout the years, many factors have contributed to the decline of these waterbirds, such as predation by introduced animals, loss of wetlands, alteration of habitat by invasive nonnative plants, disease, and possibly environmental contaminants. Hunting in the late 1800s and early 1900s also took a heavy toll on Hawaiian duck populations and to a lesser extent on populations of the other three endemic waterbirds.
Based on data from the States biannual waterbird count, none of these species consistently number more than 2,000 individuals, with the exception of the Hawaiian coot. Population estimates tend to fluctuate depending upon factors such as rainfall amount, and using waterbird counts to estimate populations has proven reliable only for the coot and stilt. Scientists have found it difficult to determine the status of the duck and moorhen due to the difficulty of distinguishing between Hawaiian ducks, feral mallards, and hybrids, and the secretive nature of the moorhen and its use of densely vegetated wetland areas. Trend data collected over the past three decades show that the Hawaiian coot, moorhen, and stilt populations are either stable or increasing.
The small, brown Hawaiian duck is closely related to the mallard, but both sexes are similar in appearance to a female mallard. Currently, Hawaiian ducks are found on the islands of Niihau, Kauai, Oahu, Maui, and Hawaii. The most serious threat to the Hawaiian duck is cross breeding or hybridization with feral mallards.
The slate-gray Hawaiian coot has a large bulbous frontal shield above its usually all white bill. The sexes are similar in color and have large feet with lobed toes (unlike ducks, which have webbed feet). A small percentage of Hawaiian coots have a red shield and black bill similar to their mainland relative, the American coot. Hawaiian coots currently inhabit all of the main Hawaiian Islands except Kahoolawe.
The Hawaiian common moorhen is similar to a coot, but has a red shield over its red and yellow bill and very long, slender toes that allow it to walk on floating wetland plants. The sexes are similar in appearance. Hawaiian common moorhens are currently found on the islands of Kauai and Oahu.
The black and white Hawaiian stilt is a slender wading bird with distinctive long, pink legs, and is considered a separate subspecies of the black-necked stilt found in North America. It differs from the black-necked stilt in appearance in that it has black extending lower on the forehead as well as around to the sides of the neck, and by having a longer bill and longer legs. Sexes are distinguished by the color of the back feathers (brownish in females, black in males) as well as by voice (females have a lower voice). Hawaiian stilts are currently found on all of the main Hawaiian Islands except Kahoolawe.
The availability of the draft recovery plan for a 60-day public comment period was announced in the Federal Register on August 24, 2005. Copies of the draft recovery plan are available through the Fish and Wildlife Service website at http://pacificislands.fws.gov or by calling the Fish and Wildlife Service Honolulu office at 808 792 9400. Written comments may be submitted until 0October 24, 2005 to the Field Supervisor, Pacific Islands Fish and Wildlife Office, 300 Ala Moana Blvd., Room 3-122, Box 50088, Honolulu, HI 96850.
