In the late 18th century, Hawadax Island in the Aleutian chain saw a major change. Following a Japanese shipwreck, this remote, then-Russian island in western Alaska saw its first encounter with rats, who fled the ship and managed to find refuge on the island. Rats don’t usually swim, but it’s well known that they can, if they have to, and they had to.
Hawadax Island is one of the smaller Aleutians, about ten square miles, populated only by seabirds. The rats found something to eat when they found the birds, pilfering their eggs, and eating the birds themselves. Once full of birds, by 1780, Hawadax Island was completely dominated by rats. In 1827, Russian sea captain Fyodor Petrovich Litke renamed Hawadax Island, which gets its name from the Aleut word for welcome, to something a little more descriptive: Rat Island.
Rat Island has been described as eerily quiet. Sailing in the Aleutians, you would normally expect to hear plenty of bird calls when you’re near land. Rat Island of course had no such sounds, since the bird populations had been decimated by rats. It’s not that the birds didn’t try to take their island back, though. Birds kept landing on Rat Island for years, seeing vacant land and trying to nets. They would lay eggs and go about life the way birds usually do. The birds in the region had evolved with no natural predators, so they never considered the possibility of being attacked. But sure enough, the rats of Rat Island would sustain themselves by attacking nests and the birds themselves. The rats also sustained themselves on the native vegetation, but they vastly preferred the birds and eggs.
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| Hawadax/Rat Island in 2009 |
In 1867, the United States purchased Alaska from Russia, along with Rat Island and all of its rats. Rat Island was generally avoided, since it had nothing to offer but more rats. Its Aleutian name of Hawadax was forgotten, and the island had only its new name. In fact, Rat Island was only one of sixteen islands in the Aleutian chain that are known collectively as the Rat Islands, though only Rat Island is the only one that has been totally overrun by rats. Over time, rats started to spread out, occasionally making beachheads on neighboring islands, landing on all sixteen of the Rat Islands, and threatening the ecosystems of all of them.
In 2007, the US Fish and Wildlife Agency decided it was time to take action. They formed a plan to eradicate the rats from the islands, and most importantly from Rat Island. Taking on Rat Island was the hardest job, and it took a major effort. The plan was to poison the rats, which isn’t as easy as you might think. The rat poison used by Fish and Wildlife had to be unattractive to birds, since poisoning the birds wouldn’t help. To keep the birds from eating the poison, they made it blue, which is a color shown to hold little interest to seabirds. Rat Island was thus bombarded with brodifacoum, a potent poison, and a major rat die-off ensued. A number of birds also ate the pellets, particularly gulls, but also some bald eagles went down in the great poisoning.
Rat Island was poisoned and repoisoned for two years, and in 2009, Fish and Wildlife declared the island officially rat-free. Maps of the Aleutians today show the island with its old name restored, and Rat Island is once again called Hawadax Island. There are other Aleutian islands that have rat infestations. These are larger islands, some with human habitation. It had long been thought that these islands were too far gone to remove their rats, and some still feel this is the case. However, the reclaiming of Hawadax Island has given hope to rat eradication efforts. Regular monitoring of Hawadax Island shows that birds have been moving back and setting up nests, but no rats are coming back.
The Hawadax Island project was difficult and expensive, but the largest rat removal program in history involved Campbell Island in New Zealand, an uninhabited subantarctic island about ten times larger than Hawadax. Rats had been introduced there around 1800, along with feral cattle and feral sheep. By 1992, the cattle and sheep were eliminated, and by 2003, the rats of Campbell Island were also gone. Campbell Island has since been repopulated by seabirds, including the Campbell duck, one of the world’s rarest birds.
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| The Campbell duck on a farm in California |
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