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.
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.
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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.
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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.