Two rat-sniffing dogs found three areas last week where rats could still be living on Lehua island in the latest operation to rid the seabird sanctuary of invasive rodents, the state Department of Land and Natural Resources said.
Henry and Reese, both border terriers, sniffed out the potential rat burrows during four days of scouring the island in grass taller than their heads and over steep and loose lava rock.
Lehua is a state seabird sanctuary, and for the past nine months has been the site of an intensive restoration project to remove invasive rats, which are a threat to native seabirds. The island is home to 17 seabird species, including several — such as the Newell’s shearwater, the black-flooted albatross and the Laysan albatross — that are considered threatened or near-threatened species, according to DLNR. It is also home to 11 plant species found only in Hawaii.
The Lehua Island Restoration Project is a program made up of state, federal and conservation organizations to protect nesting seabirds from rats, which feed on chicks and eggs and the native plants that support the island’s birds.
Last summer the state applied rat bait to exterminate the rat population, and since then monitoring teams have seen more albatrosses on the island, with no signs of rats feeding on plants or seabird eggs, something that was prevalent a year ago. The rats also endanger native and endemic plants by eating seeds, bark, fruit and leaves.
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Since last fall, however, a network of motion-triggered cameras captured seven rat images on the roughly 300-acre, crescent-shaped island west of Kauai.
“Whole island eradications are very complex, and seeing a few surviving rats is a reflection of this,” said Sheri Mann, Kauai branch manager for the DLNR Division of Forestry and Wildlife.
Border terriers are known for their ability to track rodents, and the eradication team brought in Henry and Reese to help track down the remaining rodents. Once they picked up the scent of a rodent, their handlers marked the spot for further eradication efforts and additional bait application.
The terriers, owned by Charlotte Metzler of Hawi on Hawaii island, spent months preparing for their deployment by training at the Kaena Point Natural Area Reserve on Oahu, which resembles the environment on Lehua.
Kyoko Johnson, a dog trainer who helped train the canines at Kaena Point, said a major objective of the training was to desensitize the dogs to the seabirds so they could focus on finding rats above ground and in burrows on Lehua.
While Lehua is only 279 acres in size, its topography made the canines’ rat search challenging, and the pair needed plenty of water and rest stops. Conservation detection dogs have been used before in Hawaii to locate endangered species like the Hawaiian hoary bat and the wedge-tailed shearwater, as a way to measure the impact of wind farms on those species. The U.S. Fish and Wildlife Service, one of the partners in the Lehua restoration effort, used them in a pilot study to try and detect avian botulism in the koloa maoli, the endangered Hawaiian duck.
DNLR said plans are being made for Henry and Reese to return to the island for further searches.
