Soon, No Rats on Rat Island: Seabirds to Benefit

Whiskered Auklet. Photo: USFWS

In the coming year, an island that has been an ecological wasteland for over 200 years will start on the road to recovery. In 1780, a Japanese ship ran aground on what is today called Rat Island, and rodent stowaways jumped ship to find a rat paradise. In 1922, Arctic foxes were stocked on the island by fur ranchers, further adding to the devastation. Prior to these two introduced predators, the island held thousands of nesting seabirds, including Fork-tailed Storm Petrels, Whiskered Auklets, and both Horned and Tufted Puffins. These birds were easy prey because their nests or nesting burrows remain unguarded while the parents forage at sea. The rats ate the eggs, killed the chicks, and harassed the parents until almost no seabirds returned to nest on the island.

Island restoration began in 1964, when the foxes were eradicated, and now, a solution to the rat problem seems to be at hand. The Nature Conservancy is collaborating with FWS and Island Conservation to remove all the rats from the island. Rodent eradications have proven incredibly successful at other sites. The endangered Xantus’s Murrelet saw an astounding 80% increase in nesting success when introduced rats were removed from Anacapa Island (Bird Calls Vol. 7, No. 2). However, the process is not easy. It takes years of evaluation and planning to select a target island and plan the removal effort. The Rat Island Environmental Assessment was completed this year. Removing rats from the island is also expensive. In this case, funding will come from public sources and dozens of private donors.

Rat Island is one of the Aleutian Islands, which are collectively designated by American Bird Conservancy as a Globally Important Bird Area because of their importance to seabird populations. Three of the Aleutians support more than one million birds each. There are several other islands in the chain with infestations of rats, but the next target has yet to be selected. Each island presents its own potential rewards and challenges. The size, the value to nesting birds, the presence of other invasives, the cost and the risk of reintroduction are just some of the factors to be considered. For more information, visit www.islandconservation.org.