"The mice on Gough are amongst the biggest wild house mice in the world. In winter, they eat through the 'island larder' until they start to run out of seeds and invertebrates," he said.
"At that point they increasingly start to eat seabirds, as well as other mice. A Gough winter is not a nice place to be a seabird or a mouse."
Wanless says Gough Island mice are depressing bird populations and will cause some species, such as the Tristan albatross, to go extinct if left unchecked.
The researchers believe mice become predatory when other introduced animal pests, such as rats and cats, are eliminated, freeing the mice from competition and predation.
While small in area, ocean islands sustain the world's highest diversity of bird species, the researchers note, adding that over the past four centuries, 90 percent of global bird extinctions have involved island species.
Many such extinctions have been caused or aggravated by rats, cats, and other introduced animal pests.
The researchers say that in light of their new evidence, island restoration programs should also target mice.
Free Email News Updates
Best Online Newsletter, 2006 Codie Awards
Sign up for our Inside National Geographic newsletter. Every two weeks we'll send you our top stories and pictures (see sample).
SOURCES AND RELATED WEB SITES