Atlantic Island Wins Total War Against Rats That Devoured Rare Bird Colonies

In this file photo a rat eats pieces of bread thrown by tourists near the Pont-Neuf bridge over the river Seine in Paris, France, August 1, 2017. REUTERS/Christian Hartmann

A remote South Atlantic island has finally won its long war against a rat infestation that threatened two species of rare birds.

The British Overseas Territory of South Georgia began its campaign against the rodents in 2011. After completing the last three planned phases, the South Georgia Heritage Trust announced victory on Wednesday.

The charity worked with U.S. counterpart Friends of South Georgia Island, and led the $13.5 million project which involved sending helicopters to drop poisoned pellets onto the more remote parts of the rocky landmass. The extermination team then had to wait two years to assess the impact, using sniffer dogs to comb the island for any surviving pests. Peanut butter-laden traps were also set to neutralize the rodents.

The charity claims its program is the largest rodent eradication effort ever undertaken, covering approximately 420 square miles. The team now believe the island is rat-free for the first time since humans introduced them to South Georgia more than 200 years ago.

The rats found themselves in the charity's crosshairs thanks to their voracious appetites. South Georgia is home to millions of birds, belonging to more than 30 different species. The South Atlantic's sub-Antarctic habitat means there are no trees, so birds nest either on the ground or just above it in rocky burrows.

This lifestyle made the birds vulnerable to the rodents that arrived with sealers and whalers who used the island as a base in the 19th and 20th centuries. The islands were first visited by famous British explorer James Cook in 1775, who named it in honor of King George III. Around 30 people now live on the island, which was occupied by Argentinian marines during the 1982 Falklands War.

Conservationists were particularly concerned about the safety of two rare species of bird that do not live anywhere else in the world: the South Georgia Pipit, the world's most southerly songbird, and the South Georgia Pintail duck. With no natural predators, the birds were unable to deal with the sudden influx of hungry new neighbors.

Professor Mike Richardson, chairman of the project's steering committee, told the BBC the team struggled with nerves as they waited to see if their efforts had paid off. "But I'm pleased to say over the last six months, not a single sign of a rodent has been found. And so to the best of our knowledge, this island is now rodent-free."

Now the rats are gone, the battle is to keep the island free of them. The island authorities conduct stringent checks on the thousands of tourists who visit the island every year to see the local birds, seals and penguins. Tourist ships are not allowed to dock on the island, and visitors must instead come ashore in inflatable craft after their bags and clothes are thoroughly inspected. Government and navy ships that are allowed to land must have their cargo baited and fumigated.

South Georgia's authorities remain wary of complacency. As Richardson said, "Even one pregnant rat getting back on to South Georgia could restart this whole cycle."