What is a practical solution for cleaning up henderson island

Situated more than 3,000 miles from the nearest continent, Henderson Island (Pitcairn Group, UK Overseas Territory) is one of the most remote islands on the planet. It is also the world's last large limestone island still in a near-pristine condition.

Henderson Island, view of the coastline, British Overseas Territory

Uninhabited, with almost no human influence, this remote paradise is home to more than 55 species found nowhere else on earth. These include four unique land-birds: the Henderson fruit-dove, Henderson lorikeet, Henderson rail and Henderson reed-warbler. The island, a global stronghold of the gadfly petrel group, is also the only known breeding site of the endangered Henderson petrel.

The island's beaches provide crucial nesting habitat for endangered marine turtles. Combine this with nine plant species, eight species of snail and dozens of invertebrates all endemic to this island, and it is clear that Henderson is one of the crown jewels of UK biodiversity. It is a designated World Heritage Site, making it one of the planet's greatest natural assets.

Despite being remote and uninhabited, Henderson’s unique biodiversity is currently under threat due to the presence of introduced Pacific rats. Evidence from fieldwork has shown 95 per cent of petrel chicks are killed within just one week of hatching (more than 25,000 chicks a year). Since petrels lay only one egg in a clutch, this level of predation is simply unsustainable.

Seabird numbers have dropped from an estimated 5 million pairs before rats arrived to just 40,000 pairs. The Henderson petrel is being driven towards extinction. The rats are also likely to be reducing populations of marine turtles and other wildlife on Henderson.

During August-September 2011, the RSPB, in conjunction with the Pitcairn Islands Government, undertook a ground-breaking operation to restore Henderson Island. At 43 square kilometres, Henderson was the largest tropical or sub-tropical island ever to be subject to a rat eradication operation, and the third largest island yet treated in the world. The project was also the first time an aerial eradication operation had been conducted from the deck of a ship.

However a monitoring expedition confirmed that rats are unfortunately still present on Henderson Island. There is more work to do to save Henderson's unique wildlife.

Prevent the extinction of the Henderson petrel
Boost populations of the four endemic landbird species
Increase populations of the estimated 30+ endemic invertebrate species
Allow the recovery of natural flora
Dramatically boost seabird numbers on Henderson. Research suggests populations could increase by up to a hundred-fold, creating a veritable haven for biodiversity
Involve the Pitcairn Islanders and other key groups in saving this World Heritage Site.

January 2008: A feasibility study commissioned by the RSPB found eradicating rats from Henderson Island was technically feasible, though highlighted two outstanding questions
August-September 2009: A field expedition to Henderson, part of the OTEP-funded project 'Preparing for rat eradication on Henderson Island World Heritage Site', resolved all outstanding issues and gave the green light
July-November 2011: Two field teams implemented a rodent eradication project on Henderson Island. At 43 square kilometres, Henderson is the largest tropical or sub-tropical island ever targeted for a rat eradication
March 2012: National Geographic expedition to Henderson Island films a live rat on Henderson Island. The RSPB responded
May 2012: RSPB mounted a rapid response survey and confirms rats are still present on the island
November 2012: We implement three independent reviews of the eradication operation while at the same time conduct a more detailed survey of Henderson birds and the rebounding rat population
July - August 2012: A nine week research expedition to Henderson Island, funded by the Darwin Initiative, identifies that rats are not yet back to pre-eradication levels but this will not last. The operation may have failed but for a brief period, sea and land bird fledgling success would have seen significant improvements
May - November 2015: The RSPB mounts a six-month expedition to Henderson Island. This expedition was designed to learn more about the ecology of rats and Henderson Island. The results from this expedition are already informing our strategy towards a second attempt to restore this World Heritage Site.

Henderson petrel, herald petrel, Murphy's petrel, Kermadec petrel, Henderson fruit-dove, Henderson lorikeet, Henderson rail, Henderson reed-warbler, fairy tern, masked booby, red-footed booby, great frigatebird, red-tailed tropicbird, brown noddy, black noddy, bristle-thighed curlew, wandering tattler.

The RSPB is committed to saving the Henderson petrel from extinction. Eradicating rats from Henderson Island is still the best hope for this and other endemic species and to restore this isolated tropical island for all of its nature. The Henderson Island operation was ground-breaking in many aspects and we are committed to continuing our efforts.

Mike Clarke, Chief Executive of the RSPB, said: "While everyone involved in the first attempt was bitterly disappointed to learn our efforts to eradicate rats from the island failed, we are still committed to working with the Pitcairn community to restore Henderson Island World Heritage Site.

"We are still optimistic we can eradicate rats from Henderson. However, we are not leaving this to chance. As with the first attempt, our approach will have a firm basis in science. There are a number of key questions outstanding, which we will investigate further. Our team will ensure that we have everything in place before going ahead with a second attempt."

The RSPB works in partnership with the Pitcairn Island Community, for whose support we are extremely grateful. We also work with the Royal Zoological Society of Scotland (RZSS), BirdLife International, the Royal Forest & Bird Protection Society of New Zealand, Island Conservation and Dr. Michael Brooke at the University of Cambridge.

The RSPB is very grateful for all funding received to support this important programme. Due to the complex nature of the Henderson Island Restoration Programme, funding has come from many sources including private individuals. Organisations that have supported the programme to date are: