A grand quest to rid an island of rats

Scientists carrying out the ambitious program on Rat Island hope to return the volcanic outcropping in the Aleutian chain to its original splendor as a seabird paradise.

ANCHORAGE, ALASKA
The attack force arrived at the remote Aleutian Island stealthily, ready to subdue the unsuspecting enemy, who vastly outnumbered them. It took a week’s travel just to get there, with boats and helicopters hopscotching 1,400 miles of coastline, stopping every few hundred miles – including once, harrowingly, at the base of an ash-spewing volcano.

At the final target, they dropped their ordnance – poison from the air. They also set traps by hand on the ground, trying to be as unobtrusive as possible to avoid detection. With the assault complete, they retreated to the safety of the mainland – uncertain for years whether the effort would be successful in eradicating the foe.

The “invasion” was conducted last fall by a group of scientists and technicians hoping to carry off one of the most ambitious rat-eradication efforts in the world. Appropriately enough, the target of their efforts was a volcanic outcropping in the Aleutian chain called Rat Island.

Centuries ago, Rat Island was believed to be a virtual paradise for seabirds – a spongy redoubt for tufted puffins, whiskered auklets, and storm petrels. But then came the rats, which turned the fecund habitat into a near-dead zone. Now scientists are trying to return the uninhabited island to its original splendor – an experiment that environments believe could be a model for restoration but some critics say is a waste of money.

“Rats don’t belong there, and if it makes sense to try to undo a wrong, we will,” says Vernon Byrd, a US Fish and Wildlife Service biologist who’s part of the eradication effort.

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In one sense, Rat Island’s narrative is one that has played out around the world. Rats have invaded 90 percent of the globe’s islands, threatening animals that evolved in the absence of vicious land hunters. Rats are specifically blamed for 40 to 60 percent of the recorded island extinctions of birds and reptiles – including the long-departed dodo.

Rat Island was the first site in Alaska to be invaded. Around 1780, a Japanese sailing ship wrecked off the coast, sending the muscular Norway rats swarming ashore. What started out as a few survivors mushroomed over the decades into a Ghengis Khan horde, which systematically wiped out nesting seabirds and their young. The island, once called “Hawadax” (entry) by native Alaskans, was renamed Rat Island.

Since then, a motley mix of ancient ships and modern vessels has introduced rat colonies to about two dozen Alaska communities and islands. Among the worst-hit sites is the Aleutian city of Unalaska/Dutch Harbor, one of the world’s top fishing and cargo ports.

Rats are particularly devastating in the treeless Aleutians. While the diverse marine life that takes refuge there has adapted to the rugged weather and conditions, it lacks any natural defenses against land predators. At Kiska, an island where rats tagged along successive World War II military invasions by Japanese and American soldiers, biologists fear that an auklet colony that numbers in the millions will be wiped out.

Ultimately, Rat Island was selected as the best candidate for Alaska’s first and North America’s fifth island rat-eradication project. At 11 square miles, Rat Island is small enough to be manageable but big enough to be biologically significant. As far as scientists can piece together, it was once, like the other islands in the Aleutian chain, among the world’s best seabird theaters – a place where murrelets and song sparrows thrived in sea grasses, glaucous-winged gulls dove into the surf, and winged denizens burrowed in the thick-rooted island vegetation.

It is also far enough removed from major cargo routes that experts think it unlikely to be invaded by ship-borne rats again. It is part of the sprawling Alaska Maritime National Wildlife Refuge, where the mandate is to protect the natural environment.
When the US Fish and Wildlife Service teamed up with the Nature Conservancy and other experts to launch the Rat Island project, few people objected. Misgivings were limited to worries about the unintended consequences of dropping rodenticide from the air. Federal authorities were able to make the case that this was the least harmful way of eliminating what has turned out to be a dangerous pest. “Rats don’t have a lot of friends,” says Mr. Byrd. “In most cases, I think folks see the value of restoration of native species.”

Not everyone was convinced. Time magazine in December listed a $150,000 congressional appropriation for the Rat Island project as one of the 10 “most outrageous earmarks” of 2008. Actually, the full cost is about $2.5 million, with most funds coming from private sources such as the Nature Conservancy and from fines paid by shippers for past oil spills.

Late fall was chosen as the best time to apply rat poison because any other animals in the vicinity would likely have migrated south. Though biologists will return this spring and next fall to monitor the situation, it will take longer than that to know whether the eradication worked. Even if the rats are all gone, years must pass before the habitat can return to a condition supporting large numbers of birds. “It may take several decades to build populations back up to thousands,” says Byrd.

Rat eradications have been successful on more than 300 islands worldwide, giving Bryd and his colleagues cause for hope. But Rat Island is particularly challenging because of its remoteness and weather. No other such project has been conducted so deep into snow country.

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Byrd knows the area well. After an upbringing in North Carolina and an education as a biologist, he came to the western Alaska in 1968 on assignment with the Navy. He was posted at the once-bustling Navy station on the Aleutian island of Adak. The day he was discharged from the service, in 1971, he went to work for the Fish and Wildlife Service, serving at the Izembek National Wildlife Refuge on the Alaska Peninsula. Now nearing retirement, Byrd has spent much of his career trying to help the environment by targeting “invasive” species – bird-preying foxes, vegetation-tromping reindeer and cattle, and the most persistent villain, rats.

The Rat Island project is only a small part of a broad anti-rat program that is embraced by federal, state, and local governments as well as environmental and native groups. Sweeping Alaska regulations enacted in 2007 make it illegal to own rats or harbor them, even unknowingly. Violations are criminal offenses that carry fines of up to $200,000, plus possible jail time.

Some communities have managed to keep rats at bay. Anchorage, where the rodents have long been outlawed by local ordinance, is home to the Northern Hemisphere’s biggest rat-free port. Still, the rat menace always looms. “Really, it’s a game of Russian roulette,” says Joe Meehan, a rat expert at the Alaska Department of Fish and Game. “One just might have the luck to figure out how to fend for itself and find food and shelter and fend off predators.”

The state regulations require all Alaska ports to have detailed rat-control programs similar to oil-spill contingency plans mandated after the 1989 Exxon Valdez disaster.

“Ecologically, a rat spill is much worse than an oil spill,” Byrd says. Until the recent successes at newly rat-free islands elsewhere in the world, “We assumed if rats got into an ecosystem, it was trashed forever.”