Conservationists are setting off on a voyage to one of the most remote places on earth to eradicate invasive rats from an island where they are killing endangered seabirds.
The RSPB will be destroying rodents introduced by humans on Henderson Island, an uninhabited part of the UK’s Pitcairn overseas territory, in a bid to save the endangered Henderson petrel which nests only on the island.
Rats are eating 25,000 newly-hatched Henderson petrel chicks each year on the World Heritage-listed island, driving the species towards extinction.
The Henderson petrel is the most threatened of the four petrel species which nest on the island, as it is found nowhere else in the world, but all four have seen populations plummet as a result of the rats.
The rodents, which were introduced by Polynesian settlers, eat 95 per cent of chicks alive within the first week of hatching and the number of petrels has dropped from millions of pairs 800 years ago to an estimated 40,000 now, the RSPB said.
The RSPB project, which will see it dropping rat bait on the island from the air, is part of a partnership which will see a ship and two helicopters taking a 27,000-kilometre voyage around the Pacific to complete three island restoration programmes.
Henderson Island, which is more than 3,000 miles from the nearest continent, is home to more than 55 species found nowhere else on earth including four land birds, eight species of snail and nine plants.
Its beaches provide crucial nesting habitat for endangered marine turtles.
It was declared a World Heritage site in 1988, because it was the world’s only forested atoll with its ecology virtually intact.
The RSPB believes that once the rat eradication has taken place, populations of Henderson petrels and other seabirds will increase, while as yet unknown insect species, whose numbers may have been kept very low by the rats, could be found.
Rat poison will be dropped from helicopters in a process that will take two or three days to treat the whole island. The operation will be repeated a week later to ensure no rats survive.
Richard Cuthbert, conservation scientist with the RSPB, who will be on Henderson during the eradication, said: “Our research has show that it’s possible to get rid of these rats and reverse the seabird decline on Henderson.
“Without a full-scale eradication, the wildlife on this island faces a very bleak future, with the Henderson petrel sliding towards extinction.”
The conservation voyage, setting sail from Seattle, will complete projects on the US’s Palmyra Atoll and in Kiribati’s Phoenix Islands protected area, before heading to Henderson Island in August.