South Georgia has been declared free of rodents for the first time in more than two hundred years. 

Invasive mice and rats arrived on South Georgia as stowaways on sealing and whaling vessels from the late 18th century onwards and preyed on ground-nesting and burrowing birds. 

The introduced rodents have had a devastating effect on these birds, which evolved in the absence of natural predators and were becoming increasingly confined to rodent-free small offshore islands. 

Millions of birds

Professor Mike Richardson, chairman of the South Georgia Heritage Trust  Habitat Restoration Project Steering Committee, said: “South Georgia Heritage Trust is delighted to declare that its Habitat Restoration Project is complete and that invasive rodents have been successfully eradicated from the island. 

“It has been a privilege to work on this conservation project, the largest of its kind anywhere in the world, and I am immensely proud of what the small charity has achieved – it has been a huge team effort.

He added: “The popular BBC series Blue Planet highlighted our shared environmental challenges and raised awareness of South Georgia’s importance to seabirds and nature more widely. We hope the results from this project will continue to inspire others to help protect our natural world.”

The rodents have threatened the existence of two endemic species found nowhere else on Earth: the South Georgia pipit and South Georgia pintail.

The Habitat Restoration Project was launched ten years ago with the aim of reversing two centuries of human-induced damage to the island’s wildlife, so that millions of birds could reclaim their ancestral home. 

Rodent free

The last of the poisoned bait was left more than two years ago, but scientists have continued to monitor the island for any sign of rodent life.

Deploying various detection devices including  chewsticks, tracking tunnels and three highly trained ‘sniffer dogs’, the team covered over 1500km of harsh, mountainous terrain in often extreme weather conditions to ensure the entire area was surveyed.

Richardson said: “Thanks to the outstanding work of the passionate and committed members of Team Rat and the Board of Trustees, the birds of South Georgia are free from the threat of rodents. 

“The Trust can now turn its attention and efforts to working with the Government of South Georgia & the South Sandwich Islands on conservation of a different kind: the conservation and reinterpretation of the island’s historic cultural heritage to educate and enlighten future generations about our environment.”

Lord Gardiner, the Parliamentary under-secretary at DEFRA, said: “The UK is proud to be custodian of the precious and unique biodiversity of 14 Overseas Territories, most of which are island environments, like South Georgia, that are highly vulnerable to environmental change.

“The last ten years has seen a step-change in how the UK responds to invasive non-native species and the rodent eradication work completed by the South Georgia Heritage Trust is undoubtedly among the most remarkable of recent island conservation efforts. This successful project gives confidence and offers hope for invasive alien species management around the globe.”

This Author

Catherine Harte is a contributing editor of The Ecologist. This story is based on a news release from The South Georgia Heritage Trust.