Saving Henderson Island’s birds

From BirdLife:

Aircraft carrier and helicopters come to unique island’s rescue

Tue, Dec 20, 2011

A ground-breaking $2.3million RSPB (BirdLife in the UK) project to eliminate introduced rats from an uninhabited island in the central Pacific has attempted to remove the fingerprints of man from an otherwise idyllic tropical paradise. As a bonus, the project has also increased the known size of the UK’s overseas territories by six square kilometres.

Henderson Island, one of the UK’s most remote territories and a World Heritage Site, has been ravaged by Pacific Rats, introduced by the Polynesians eight centuries ago. The rats were destroying the island’s habitats, driving the Endangered Henderson Petrel Pterodroma atrata towards extinction, and significantly damaging the populations of four other bird species, rare plants, insects and snails all found nowhere else on earth. There were millions of ground-nesting seabirds on Henderson before rats were introduced to the island, but their numbers have been reduced to just 40,000 pairs today. Early results indicate that the seabird population will boom if the rats have been successfully removed.

The mission – a partnership with the Pitcairn Islands Government – was one of the most complicated the RSPB has ever undertaken, and involved a voyage of 27,000 kilometres in a purpose-built aircraft carrier, capable of handling two helicopters from its temporary flight deck. It hopes to have removed introduced rats from Henderson Island by dropping poison rat pellets from giant hoppers suspended beneath the choppers with sufficient accuracy to land a few feet apart across the entire island.

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Covering 43 square kilometres, Henderson Island is over 3,000 miles from the nearest mainland in South America. It is the world’s only forested atoll with its ecology virtually intact, and the largest tropical or sub-tropical island ever subject to a rat eradication attempt. Although the results won’t be known until 2013 – when rat surveyors visit the island – the RSPB remains extremely hopeful that the project has eradicated rats from the island, as no previous aerial operation to remove Pacific rats has failed.

Non-native species, such as rats, have been one of the greatest drivers of extinction of birds, especially on remote islands where the native wildlife has evolved in isolation away from predatory mammals. Although it’s too late for some now-extinct species, the RSPB hopes that the project has thrown Henderson Island’s unique wildlife a lifeline, including four species of landbird found nowhere else on earth: a fruit-dove; a lorikeet; a reed-warbler and a rail: a relative of moorhens and coots.