In 1780, a Japanese ship foundered off the coast of a remote Aleutian island, and the Norway rats in the hold lived up to their reputation by fleeing the sinking ship. Then they got busy feasting on the eggs of the island's ground-nesting seabirds and multiplying, until the spot earned the name Rat Island.

To eradicate the rats, biologists set out in helicopters in September 2008 and rained down tasty poison pellets. Nine months later, a survey didn't turn up a single live rat. There was a downside: researchers found the carcasses of dozens of gulls and bald eagles that presumably ate the poisoned rats, and perished as well. Still, researchers say that if the rats really are gone for good, the birds can recolonize the island and will ultimately be better off.

Status: Looking Good