The Subantarctic island of South Georgia had been troubled by rodents for centuries. Brought in by whalers and sealers, rats and mice devastated the bird colonies and the vegetation. Over the last 10 years, however, things have changed for the better. In the world’s largest eradication program, more than 1’000 km2 of the island were cleared of any rodents. Now, the South Georgia Heritage Trust has declared the campaign a huge success.

South Georgia is situated right in the middle of the South Atlantic and Southern Ocean. Due to its remoteness, only seabirds and marine animals made the place their home, at least until the arrival of human beings. Credit: Michael Wenger
South Georgia is situated right in the middle of the South Atlantic and Southern Ocean. Due to its remoteness, only seabirds and marine animals made the place their home, at least until the arrival of human beings. Credit: Michael Wenger

After nearly a decade of planning and four sub-Antarctic seasons of work by an exceptional international team, the South Georgia Heritage Trust (SGHT) has declared South Georgia free of rodents for the first time since humans arrived on the island more than two centuries ago. Professor Mike Richardson, Chairman of the SGHT 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. The popular TV 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.”

Rats and mice had travelled on board of whaling and sealing ships in the 18th and 19th century and landed on South Georgia when ships were either beached or had made camp ashore. With no concurrence or enemies, the rodents multiplied quickly. Credit: Paula O’Sullivan
Rats and mice had travelled on board of whaling and sealing ships in the 18th and 19th century and landed on South Georgia when ships were either beached or had made camp ashore. With no concurrence or enemies, the rodents multiplied quickly. Credit: Paula O’Sullivan

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.  In particular, the rodents have threatened the existence of two endemic species found nowhere else on Earth: the South Georgia pipit and South Georgia pintail. Scottish-based charity SGHT started planning its ambitious Habitat Restoration Project in 2008, 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.  The Trust launched the pilot phase of baiting in 2011, followed by a second phase in 2013/14 and a third phase in 2015/16.  This first phase of baiting alone - completed in just 28 days despite the harsh sub-Antarctic conditions - made this project the largest island rodent eradication operation ever undertaken in the world.  Since the last baiting phase in 2015/16, no sign of rodents have been detected with some bird species already showing very dramatic signs of recovery, but a comprehensive survey was essential before the island could officially be declared free of rodents.

With the use of helicopters, New Zealand pilots and a very dedicated Team Rat, the poisoned bait was delivered over all rodent-infested areas of South Georgia in 3 phases and over a period of 4 years. The last phase included a monitoring survey with specially trained dogs. Credit: SGHT
With the use of helicopters, New Zealand pilots and a very dedicated Team Rat, the poisoned bait was delivered over all rodent-infested areas of South Georgia in 3 phases and over a period of 4 years. The last phase included a monitoring survey with specially trained dogs. Credit: SGHT

Following international best practice, more than two years after the last baiting work, an expedition team – dubbed ‘Team Rat’- spent six months on South Georgia this past winter in the final phase of the project, assisted by representatives of the Government of South Georgia & the South Sandwich Islands, searching for any signs of surviving rats using a combination of detection methods. Over 4,600 inert devices, including chewsticks and tracking tunnels, were deployed and checked as part of the survey.  The very best rodent detection experts were also brought in especially: three highly trained 'sniffer' dogs and their two skilled female handlers. In an incredible feat of endurance and teamwork reminiscent of Sir Ernest Shackleton’s epic crossing of the island just over a hundred years ago, the handlers walked a total of 1608km, with the dogs covering a total of 2420km, searching for signs of rats.  This distance, roughly the equivalent of a return trip from London to Dundee, is all the more impressive given the rugged and challenging terrain of South Georgia. Together, the handlers climbed the equivalent ascent of Mount Everest 8 times over, and the dogs climbed Mount Everest 12.9 times over.

Three sniffer dogs and two dog handlers had searched all baited areas for rodents in a last monitoring survey. They thereby covered more than 1’500 km (handlers), resp. 2’400 km (dogs) and had climbed the equivalent of several times the Mount Everest. Credit: Oli Prince
Three sniffer dogs and two dog handlers had searched all baited areas for rodents in a last monitoring survey. They thereby covered more than 1’500 km (handlers), resp. 2’400 km (dogs) and had climbed the equivalent of several times the Mount Everest. Credit: Oli Prince

Richardson commented: “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.” The Trust, along with its US-based counterpart the Friends of South Georgia Island (FOSGI), raised £10million to finance the entire Habitat Restoration Project, securing financial and in-kind support from numerous individuals, foundations, businesses, and government, including £885K from the UK Government through DEFRA and the Darwin Initiative. Lord Gardiner, Parliamentary Under-Secretary, 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.”

With the rodents gone, bird life can restore itself and chicks will be safe from predation by rats. An estimated 100 million additional birds could potentially make South Georgia their home again. Credit: Sally Poncet
With the rodents gone, bird life can restore itself and chicks will be safe from predation by rats. An estimated 100 million additional birds could potentially make South Georgia their home again. Credit: Sally Poncet

Source: South Georgia Heritage Trust