Invasive mice and rats have devastated the U.K. island of South Georgia since the late 1700s. But thanks to the “largest eradication project” ever, it's now rodent-free.Researchers known as “Team Rat” who worked on the $13.5 million project finally hailed their efforts a success after decades of planning, according to a news release on Wednesday. The predatory rats first invaded the island as stowaways on whaling ships and began targeting the eggs and chicks of seabirds. Their hunting eventually threatened two particular species, found only on the island.The eradication project took four phases: During the first three in 2011, 2013, and 2015, researchers from the South Georgia Heritage Trust dropped poisoned bait from helicopters and also by hand at old whaling stations. This year, surveyors with search dogs scoured the island for 28 days in frigid temperatures for rats and mice. They found none.The two birds threatened by rodents — the South Georgia Pipit and the South Georgia Pintail — have already shown dramatic signs of recovery. But South Georgia is a haven for other wildlife as well. It’s home to 98 percent of the world’s Antarctic fur seals, as well as half of the world’s elephant seals, according to the South Georgia Heritage Trust. Four species of penguin also nest on the island.A British explorer and his crew were the first known humans to set foot on the sub-Antarctic island, in 1775. About 2,000 people used to inhabit South Georgia, but everyone abandoned the area after the collapse of the whaling industry. Today, the island’s inhabitants are confined to two scientific research centers.Cover image: The U.K. overseas territory of South Georgia is free of invasive rodents, which have been arriving as stowaways since Captain Cook discovered the southern Atlantic Ocean island in 1775, for the first time in more than 200 years. (Kirsty Wigglesworth/PA Wire URN:36391907 Press Association via AP Images)