Tristan da Cunha - Edinburgh of the Seven Seas

The fourteen UK Overseas Territories are scattered across some of the furthest flung corners of the globe. However, the most important for birds is probably Tristan da Cunha, which also lays claim to being the remotest inhabited place on earth.

As well as 300 islanders, the mountainous archipelago is home to millions of pairs of seabirds, and several unique land birds.

Some 200 miles from the main island group is the World Heritage Site of Gough Island, arguably the most important seabird island in the world - and British!

The RSPB, with partners at the University of Cape Town, aims to help the Tristan Agriculture and Natural Resources Department (ANRD) conserve the Territory’s natural riches.

Unfortunately, albatrosses and petrels, including three species that nest nowhere else, fall frequent victim to longline fishing. The RSPB and BirdLife International campaign for more albatross-friendly fishing practices.

Rats and mice

On the islands themselves though is a far more insidious threat. Rats and mice reached the archipelago on board boats. The chicks of petrels and albatrosses have evolved on islands with no land mammals, and have no defences when such predators arrive.

Rats have destroyed many great seabird colonies around the world, after introduction by humans. On the main island of Tristan da Cunha the once vast colonies of petrels are now reduced to sorry remnants. The other islands (Nightingale, Inaccessible and Gough) are rat-free and it is vital that they remain so.

However, a few years ago, researchers discovered that Gough’s house mice have learned to attack and kill seabird chicks, even up to full-grown Tristan albatross chicks.

This predation is widespread and devastating.Tristan albatrosses and Atlantic petrels, unique to the Territory, are inexorably declining. We don’t know what is happening to the numerous smaller storm-petrels and diving-petrels, but the signs are very bad.

Hope for the future

However, there is hope: it may be possible to rid Gough of mice and Tristan of rats. A partnership of the RSPB, ANRD and University of Cape Town developed a project, funded by the UK Government’s Overseas Territories Environment Programme (OTEP), to investigate the feasibility of eradicating rodents from the archipelago.

This is, however, a tall order. The islands are large, rugged and have a ferocious climate. There are probably more than one million mice on Gough, and if even one pair survives, we would be back to square one. Pioneering successes in New Zealand have shown that using precision drops of poison bait dropped from helicopters, it is possible to restore seabird islands, with dramatic results.

Our aim is to establish what the conservation case is for eradicating rodents from Tristan and Gough: what would be gained if we succeed; and what would be lost if we did nothing. Secondly, we need to assess whether eradication is feasible, asking the question: if attempted, is there a very high chance of succeeding?

We also need to decide what further research and development is required to ensure success. Finally, we need to produce a very detailed plan of exactly how an eradication would proceed: this is the recipe for success, ensuring that all possibilities are covered.

Acknowledgements

The RSPB works in partnership with University of Cape Town and Tristan’s Agriculture and Natural Resources Department. Funding has been provided from the UK Government’s Darwin Initiative and Overseas Territories Environment Programme. We are extremely grateful to the people of Tristan da Cunha and the Island Council for their support, and to successive Administrators of Tristan da Cunha, especially Mike Hentley and David Morley.

We would also like to thank the South African Directorate: Antarctic and Islands, Table Bay Marine (Cape Town), Ovenstones Agencies Pty Ltd and the skippers of the SA Agulhas, RV Edinburgh and RV Kelso for assistance with the logistics of travel and accommodation on Tristan da Cunha and Gough.