As well as around 300 islanders, this mountainous island group is home to millions of pairs of seabirds, and several unique land birds. It includes the World Heritage Site of Gough and Inaccessible Islands: Gough is arguably one of the most important seabird islands in the world.
Unfortunately, albatrosses and petrels, including three species which nest nowhere else, fall frequent victim to longline fishing. On the islands themselves 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 terrestrial mammals and have no defences when such predators arrive.
Rodents 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 tiny remnants. On Gough Island, researchers discovered that Gough’s house mice have learned to attack and kill seabird chicks, even Tristan albatross chicks which are a whopping 300 times the size of the mice. This predation is widespread and devastating. Tristan albatrosses and Atlantic petrels are declining fast.
Fortunately, two other islands (Nightingale and Inaccessible) remain rodent-free and it is vital they remain so – they are havens for seabirds and endemic land birds such as the rarest British bird, the Wilkins’ bunting which is found only on Nightingale, and the world’s smallest flightless bird, the Inaccessible rail.
Species at risk in the Tristan island group
Tristan albatross, Gough bunting, Atlantic yellow-nosed albatross, spectacled petrel, Tristan thrush, Inaccessible rail, Inaccessible bunting, Nightingale bunting, Wilkins’ bunting, sooty albatross, Atlantic petrel, MacGillivray’s prion.