Giant mice are killing millions of endangered Tristan albatross chicks on a remote island in the South Atlantic, threatening the rare seabird species with extinction, a wildlife organisation has said.
According to a study from the Royal Society for the Protection of Birds (RSPB), at least two million chicks are lost annually.
Just 2,000 pairs of albatrosses remain on the Gough Island — a remote UK Overseas Territory, which is considered world’s most important seabird colonies, hosting more than 10 million birds.
The albatrosses mate for life and produce just one egg every other year.
The rodents that were introduced to the 91-sqkm volcanic island by sailors during the 19th Century have learned to eat the eggs and chicks of the many millions of birds that make the island their home.
Video cameras have recorded groups of up to nine mice eating the chicks alive. Parents have been recorded returning with food to find their chicks dead in the nest. At this rate extinction looks certain within decades.
Adapting to the limited resources on the small island by developing a taste for seabird eggs and chicks, the mice have become "super-sized". They are about 50 per cent larger than a domestic mouse.
"Many of the seabirds on Gough are small and nest in burrows," said Anthony Caravaggi of the University College Cork, in Ireland.
"The chicks are smaller and have no escape route, so for an opportunistic mouse these chicks constitute relatively easy prey.
"The mice have done so well growing bigger and have now moved on to attacking all seabirds, even Tristan albatross chicks, which are far bigger than other, smaller sea-going birds."
"Not will only the Tristan albatross be lost in a very short span but a large number of other species as well," said Caravaggi. The Atlantic petril and MacGillivray’s prion will follow suit.
The RSPB and the Tristan da Cunha government, who are custodians of Gough island, have developed a plan to wipe the mice out completely by 2020.
It would be an enormous logistical challenge, involving chartering a ship from South Africa, which will carry two helicopters and a load of poisonous, cereal pellets.
These will then be spread across the island by the helicopters. They contain an anticoagulant which should kill the mice within 24 hours.
"Ridding islands of invasive species has been done on around 700 islands worldwide," said Alex Bond, from the Natural History Museum, another author on the paper.>