In the late 1700s, a Japanese ship ran aground on a desolate scrap of land in the Aleutian Island chain on what is now Alaska. Among the cargo spilled out of the ship that day were common ship stowaways: rats.
From there, the story echoes that of countless islands where the introduction of rats, cats, weasels and other predators upends the ecosystem. The island's nesting seabirds had no defenses against the predatory rats, which ate their eggs and their young. The island's bird population was soon devastated and the 10-mile (16 kilometer) square slip of land became known as "Rat Island."
In a new book, "Rat Island: Predators in Paradise and the World's Greatest Wildlife Rescue," (Bloomsbury USA, 2011), journalist William Stolzenburg tells the story of what happened when conservationists decided to take the island back. In 2008, conservation groups The Nature Conservancy and Island Conservation joined with the U.S. Fish and Wildlife Service (FWS) to bait the island with enough rat poison to wipe out the whole population of invasive rodents.
In August 2010, biologists declared Rat Island rat-free. But the scheme didn’t come without costs, including the deaths of 320 glaucous-winged gulls and 46 bald eagles that had directly or indirectly ingested the poison. Nonetheless, FWS authorities have said the eradication effort will allow tens of thousands more birds to thrive.
LiveScience spoke with Stolzenburg about the controversy around reclaiming islands and the importance of protecting these isolated ecosystems.
LiveScience: What drove you to write about Rat Island?
I have been covering the field of wildlife conservation now for about 20 years. It's kind of, after a while, a depressing beat. Most of the stories are about loss. This was a story that struck me as an incredible story of success, of hope. The idea that with one swipe, you could essentially rescue a million seabirds — you could take an island and by eliminating the rats, you could resurrect the island, you could turn the clock back, you could right all these wrongs. It was an incredible story of hope.
It was also an incredible story of controversy. I'm talking about the invaders that need to be killed, including rats, cats, weasels, foxes. It's a sad fact that we're having to kill them. That's the one downside, the controversial side. [Image Gallery: Invasive Species]
LiveScience: Why are these types of island reclamation projects often controversial?
There is another side to this issue: people who believe that we should not kill the rats, we should let them be, that they've made it there, that we should just let nature take its course. There's another argument that admits the rats are making a dent in the seabird population, but we should find a humane way to get rid of them, we should sterilize them or remove them all by live trap.
Most of these ideas are pretty untenable, and it leaves the conservationists in a bit of a quandary. They don't have the time to wait for new [humane] technology. There are those that, although they are vocal about doing better for the rats, they haven't really come up with a more practical, workable solution.
LiveScience: Do these conservation efforts put other animals in danger besides the ones being removed?
There are native rodents on some of the islands that are now being defended. There's a chapter in the book about an island called Anacapa off the coast of Southern California. This island has a native mouse called the Anacapa deer mouse, a cute little thing. When they went to eradicate the black rats that had been introduced there, they had to deal with this native rodent and some other birds that were going to be collateral victims. They actually took hundreds of these mice and kept them in captivity while they did the killing, and then they released them back. As I understand it, that project has been a success.
LiveScience: Did you travel to Rat Island or the other endangered islands in your book?
I was very fortunate and I got to visit New Zealand. New Zealand is the archetype of endangered islands, because this is the last great island landmass to be settled. It was a kingdom of birds,many of them flightless, half of them extinct since people and mainland predators arrived. [Editor's note: The only land mammals native to New Zealand are bats.]
I got to visit there and see what an island with no native mammals is like and see what happens when an island of these innocent walking birds is invaded by mammals. It's a sorry tale.
I was also very fortunate to get out and visit Rat Island and a neighboring island, Kiska. Kiska was not invaded by rats until World War II. It took a few years for these rats to make their way over this very harsh tundra, but they did, and they made it to this incredible seabird colony. There are so many birds in this colony that even the scientists have thrown up their hands. They can't estimate them. Some say there's a million, some have said it's at least 10 million. It's just one of wildlife's most amazing spectacles. [Gallery: The Beauty of Rat Island]
Well, this spectacle in the past 20 years was finally invaded by those World War II rats. Scientists have been studying it ever since, and they've seen years in which the rats were slaughtering these helpless seabirds. Worries for the future of this world-class colony is what spurred the efforts to eliminate rats on Aleutian islands. Kiska was too large and complex to start with, but Rat Island was a good practice ground.
LiveScience: What is it important to understand what's happened on these lost islands?
For one thing, it's a pretty good adventure yarn. This is a different sort of conservation campaign. It's combining your egghead academics along with professional hunters and even some semi-retired poachers.
But as for why we should care, Rat Island is a good metaphor for what's going on in the larger world. If you've ever been to an island that's mad with seabirds, you know the cacophony, the spectacle of life. You go to Rat Island, and you feel the silence and the sterility. That's a good metaphor for what's happening on mainlands around the world during this sixth mass extinction that we humans are helping along.
There's probably a million and one practical reasons why we shouldn’t be squandering biodiversity so blithely. I think there's also a case to be made for the sheer wonder of it all. These species are works of art every bit as valuable as the best van Gogh or piece of music by Mozart. If we don't do something now, 20, 30, 40 years down the road we don't have the luxury to say, "Oops, we goofed." Extinction is forever, and we need to remember that.