The world’s most extensive island rat eradication has been completed with a final load of bait dropped on subantarctic South Georgia Island from a helicopter.
The flight was made by New Zealand pilot Peter Garden and the bait dropped using a specialised spreader developed and made in New Zealand.
That the huge operation on the British territory off the southern tip of South America was possible at all was the result of 50 years of techniques and experience developed on New Zealand islands.
The eradication over 100,000 hectares was eight times larger than the previous largest on Australia’s Macquarie Island.
University of Auckland biologist and eradication expert James Russell said it was globally significant.
“They didn’t just do an incremental change – they did a step change. They moved from 11,000 hectare Campbell Island and 13,000 hectare Macquarie Island, they just grabbed the bull by the horns and went for it.”
It all began in 1964, when the late Don Merton and fellow conservationists declared that they had got rid of Norway rats on tiny Maria Island, in the Hauraki Gulf. At that time just 0.5 percent of New Zealand islands were free of mammalian pests; today, 10 percent are pest-free.
Following Maria Island, conservationists began to tackle larger and larger islands, such as 170 hectare Breaksea Island in Fiordland and then 2000 hectare Kapiti Island.
When Norway rats were eradicated from remote Campbell Island in 2001, it was a monumental conservation achievement that suddenly opened up the possibility of restoring large islands around the world.
The Campbell Island programme, led by Peter McClelland, managed to overcome the obstacles of distance – 700km from mainland New Zealand – and ferocious subantarctic weather.
Its team used five helicopters with specialised bait-spreading buckets and GPS to distribute bait containing rodenticide Brodifacoum across the entire island, including the steep cliffs.