Cape Town - Like something out of a horror movie, huge mice on Gough Island in the south Atlantic come out at night and eat baby birds alive.
The seabird chicks just sit on their nests and get gnawed. They are not evolutionary-wired to deal with mammalian predators,as there were none on Gough Island until seal-clubbers accidentally brought them ashore in the 19th century.
These bigger-than-average house mice eat around one million chicks and eggs a year on Gough Island, and experts say if left unchecked, some of these endangered seabirds are likely to become extinct. Scientists say 90 percent of bird extinctions in the past 500 years have been island species.
But now there is a plan to get rid of the mice by dropping poisoned pellets from helicopters over the island. Feasibility studies have been done, as have helicopter trials with non-toxic pellets, and experts have agreed it will work. The big problem is money: the eradication project will cost £7.6 million and funding has not yet been secured.
Gough is a British island, a Unesco World Heritage Site, on which South Africa has run a weather research station since 1956. Apart from the station, the island is uninhabited. It lies almost midway between South Africa and South America, in the Roaring Forties, and is an important breeding ground for 23 seabird species, some of which are threatened globally.
Alex Bond, senior conservation scientist at the Royal Society for the Protection of Birds (RSPB), said his organisation has worked on Gough Island in partnership with the government of Tristan da Cunha for more than 15 years.
“As research developed, so did our understanding of the serious threat mice pose to Gough Island. Eradication of mice is the only viable way to prevent loss of species. Research has shown that it is technically possible,” Bond said.
It was only in 2001 that researchers first proposed that mice were probably responsible for the high death rate of Tristan Albatross chicks. Later studies by Ross Wanless, Peter Ryan and RJ Cuthbert found that mice killed a wide range of seabird chicks.
This year Ben Dilley of UCT and other researchers published a paper in Antarctic Science that showed mice also preyed on all species of petrel chicks that lived underground in burrows on Gough. Using motion-activated cameras Dilley watched chicks attacked by mice within hours of hatching.
“The mouse would grasp the chick with its front feet and gnaw at one spot until the chick’s skin was broken. Mice appeared to attack whichever part of the small chick was exposed, starting with the rump, top of the head or back of the neck. Some adult birds dropped their wings to cover their newly-hatched chick, but the mice pushed underneath the wing,” Dilley wrote.
Almost the entire world population of Atlantic petrels breeds on Gough.
Bond said the poison project was planned for 2019, but raising the money was a huge undertaking.
“The longer we wait the more seabird chicks will be lost to mice. We need a suitable vessel, helicopters and regulatory approval. A full environmental impact assessment will be done. The programme is not yet funded. Without £7.6 million, the cause is lost. Planning can only progress so far before we will have to stop due to lack of financial resources,” Bond said.