Killer Mice Discovered on Additional Islands
- Wherein we learn that how to kill mice requires two months of research.
Killer mice threatening seabirds with extinction
By Richard Gray, Science Correspondent, Sunday Telegraph
Last Updated: 11:56pm BST 07/04/2007
Swarms of carnivorous mice are pushing rare species of island-dwelling seabirds to the brink of extinction, sparking a desperate
mission to control the rodents.
Scientists have found that normally innocuous common house mice living on islands in the south Atlantic have evolved to prey
upon the giant chicks of albatross and other seabirds, some more than 150 times bigger than themselves.
The extraordinary behaviour was initially thought to be restricted to the mice on just one island, but researchers have now
discovered evidence that young sea birds on other islands are also coming under attack.
Biologists are to spend two months on one of the remote islands to find the best way of eradicating the mice, which were
introduced there by passing ships in the 19th century.
They fear thousands of albatross, sheerwater and petrel chicks are falling victim to the mice every year.
On Gough Island, part of the Tristan da Cunha islands, about 1,000 endangered Tristan Albatross chicks - about 70 per cent of
all those born - are being taken by the mice. The island, a British territory 1,700 miles off the coast of South Africa, is the
breeding ground for almost the entire world population of these rare birds.
"The scale is sufficient to drive extinctions," said Ross Wanless, an ornithologist at the University of Cape Town, who has been
researching the killer mice. "We had no idea that mice could do this sort of thing."
Mr Wanless has captured the first film footage of the mice - which are the only foreign mammals on Gough Island - attacking the
defenceless chicks in their nests.
Swarms of 10 mice at a time can be seen gnawing at the chicks' bodies until they eventually die through blood loss or
destruction of vital organs. Chick carcasses found later are reduced to little more than skin and bones.
An albatross chick weighs more than 20lb, about the size of a goose, while a mouse weighs just two ounces
However, the researchers say the chicks make no attempt to fight back and seem not to know how to respond, perhaps because the
mice are not native to the islands, and so the birds have not evolved ways of protecting themselves.
It is estimated that it will cost £5 million to rid Gough Island alone of its 700,000-strong mouse population, and scientists
fear there are at least another four islands dotted around the South Atlantic where they are causing similar devastation.
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