Monday, December 22, 2008

Lehua rat eradication launches in January

Government officials will begin the restoration of little Lehua Island's natural habitat early in January, after several years of planning.

The rabbits that ate off much of the island's native vegetation have already been removed, and the next step will be control of rats, which have been eating seeds, live plants and birds.

(Image: Lehua from the air. Credit: NASA image via Google Earth.)

A supplemental environmental assessment for the project was completed earlier this year. (See our previous post at One of its recommendations was the timing of the predator control for a time when bird populations on the island are lowest.

The rat control project will employ the aerial distribution of a rodenticide, diphacinone.

The same compound was used for the removal of rats from Mōkapu Island off Molokai, and it displayed low toxicity to native birds and marine life. Diphacinone has been used worldwide for the removal of invasive rodents from island habitats. At Lehua, followup testing will be performed to determine whether there is any residue in either land or marine species.

“Rats are known to have eliminated many seabird species from islands around the world by eating bird eggs and preying on live birds,” said an announcement from the U.S. Fish and Wildlife Service and the state Department of Land and Natural Resources.

Wildlife officials hope that once the rats are gone, some of the native vegetation will return naturally, but they also propose a plant restoration project, in which species known or believed to have occurred on the island will be planted.

Lehua Island is a 310-acre tuff cone, similar in shape to better-known Molokini off Maui. It lies less than a mile off the north end of Ni'ihau and is about 20 miles from the west side of Kaua'i. Sixteen species of seabirds nest there, although the number may have been higher before the rats and rabbits.

For more information on the project, call Chris Swenson, U.S. Fish and Wildlife Service at 808-792-9400 or Thomas Kaiakapu, Department of Land and Natural Resources at 808-274-3443.

©2008 Jan TenBruggencate

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