Rat clearing timeline on Lehua Island altered

In an effort to complete the Lehua Island Ecosystem Restoration Project, a Draft Supplemental Environmental Assessment was recently released by the U.S. Fish and Wildlife Service and the state Department of Land and Natural Resources’ Division of Forestry and Wildlife.

The USFWS and the DLNR are seeking public comment on the draft EA and will be holding a public meeting from 7 to 9 p.m. July 24 at the Waimea Neighborhood Center in Waimea.

The draft EA is a supplement to a final EA that was approved in September 2005 with a Finding of No Significant Impact for proposed actions to protect and promote native Hawaiian species on Lehua Island.

The draft EA focuses on changes to the non-native rat eradication plan addressed in the 2005 final EA.

By eradicating the rats, the project will protect and restore native plants, wildlife and seabirds to the island.

“Rats eat many native species, including seabirds, eggs, chicks and sometimes adults; native plants, seeds, leaves and roots; and native invertebrates, insects as well as interidal invertebrates like crab,” Chris Swenson, Pacific Islands Coastal Program Coordinator for the USFWS, said in an e-mail.

The Polynesian rats (Rattus exulans) were first documented on Lehua Island in the 1930s, Swenson said.

In order to get rid of the rats, bait pellets containing the poison diphacinone will be dropped over Lehua Island using a bait hopper carried under a helicopter. Diphacinone, an anticoagulant, is a form of rodenticide that causes internal hemorrhaging in rodents, resulting in a painless death.

This method was recently used on the Mokapu islet off the north shore of Moloka‘i in February.

The purpose of the draft supplement EA is to describe and address the impacts of modifications to the rat eradication. More effective changes to the plan have also been determined while minimizing and avoiding negative impacts to non-target species.

Primary changes to the original EA include: The eradication will take place during the winter months, December through February, when the rat population and native non-target migratory species present on Lehua Island are in the lowest numbers; if the application of the bait pellets happens after the hatching of albatross chicks, all pellets within six feet of each nest will be manually removed so the chicks cannot accidentally eat the pellets; and aerial application is found to be more effective in the distribution of the bait pellets over the rough terrain of the island — it also results in fewer disturbances to native seabirds and monk seals.

Along with rat eradication, the final EA in 2005 also addressed a rabbit problem on Lehua Island. The rabbits were successfully removed in 2005 and 2006 through hunting efforts.

“The plan was to first get rid of the rabbits on Lehua Island,” Scott Fritz, DLNR wildlife program manager, said. “We had to give that time to make sure they were in fact gone, then we can concentrate on the rats.”

Fritz said the rabbits were the primary threat to plants on Lehua Island.

“Once the rabbits and rats are removed, we expect the vegetation to recover quickly on its own,” Fritz said.

Swenson said there are plans to restore native plants, seabirds and native land snails once the rats are gone.

“Rat eradication will clear the way for native species to come back to Lehua on their own or be re-introduced as part of the restoration plan,” Swenson said. “Species we hope to bring back include rare and endangered species, such as the Newell’s shearwaters.”

The uninhabited island of Lehua is located less than a mile north of Ni‘ihau and about 20 miles west of Kaua‘i. Lehua is a 290-acre, crescent-shaped island administered by the U.S. Coast Guard and managed by the DLNR as a state bird sanctuary.

Copies of the draft EA can be found online at www.fws.gov/pacificislands/ or by contacting the Pacific Islands Fish and Wildlife office at 792-9400. Written comments should be addressed to Chris Swenson, U.S. Fish and Wildlife Service, 300 Ala Moana Blvd., Room 3-122, Honolulu, 96850, or faxed to 792-9580. All written comments must be postmarked by Aug. 7.

The public comment period for the draft EA began July 8 and will end on Aug. 7.

• Rachel Gehrlein, staff writer, can be reached at 245-3681 (ext. 225) or rgehrlein@kauaipubco.com

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