Alaska’s Rat Island needs a new name this week.

The US Fish and Wildlife service reports that a massive poisoning campaign appears to have rid the island, which is in the Alaska Maritime National Wildlife Refuge, of the rodents brought there by a shipwreck in 1780. Native bird populations were heavily damaged by the rampaging rats.

“After more than two weeks of intensive field monitoring … biologists have found no sign of the invasive rats that have decimated native bird populations for more than 200 years,” says the FWS.

However the poisoning may have had some sad side effects.

The field monitoring also turned up an unexpected number of bird deaths: 157 juvenile and 29 adult glaucous-winged gull carcasses and a total of 41 bald eagle carcasses were found. At present the cause of death is not known but the FWS says it is “very concerned” by the levels of mortality.

Birds were not expected to be harmed by the poison drop.

“It’s really a puzzle to everyone,” says spokesman Bruce Woods (KTUU). “There’s a lot of people who want to know, because it doesn’t seem to make any sense at this point.”

However he adds that if the rats have been eliminated the long term benefits will outweigh the loss of these birds (Scientific American).

At the moment no rats have been seen on the island but Woods warns, “we don’t know that there’s not a couple of happy rats hiding away that are going to spring out and repopulate the island” (Reuters).

More coverage

Island has dead birds, no rats – Anchorage Daily News

Image top: Rat Island / FWS

Image lower: sign from St. Paul Island