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Plague of Mice eating chicks

Supersize mice decimate island's seabirds

Invasive, introduced house mice, three times the size of those in Europe, are devastating seabird populations on the remote Gough Island in the South Atlantic.

Gough Island is the most southerly of the Tristan da Cunha group (a UK Overseas Territory). There are 22 bird species nesting on the island of which 20 are seabirds. Dr Geoff Hilton, a Senior Research Biologist at the RSPB (BirdLife in the UK) said, "Gough Island hosts an astonishing community of seabirds and this catastrophe could make many locally extinct within decades. We think there are about 700,000 mice, which have somehow adapted to eat chicks alive."

Among the affected species are the endangered Tristan Albatross Diomedea dabbenena, which has around 2,000 annual breeding pairs restricted to Gough Island and St Helena. "The albatross chicks weigh up to ten kilograms. Ironically, albatrosses evolved to nest on Gough because it had no mammal predators – that is why they are so vulnerable. The mice weigh just 35 grams; it is like a tabby cat attacking a hippopotamus," said Dr Hilton.The island also hosts 99 per cent (around 1.8 million pairs) of the world’s Atlantic Petrels Pterodroma incerta – classified as Vulnerable. Around 60 per cent of all chicks (a staggering 700,000) die before fledging, probably because of mice predation.

The predatory behaviour of the mice was suspected then confirmed by Dr Richard Cuthbert, a RSPB researcher, and Ross Wanless, a PhD student from the University of Cape Town’s Percy FitzPatrick Institute. Ross Wanless recorded dramatic video footage of the attacks in 2004.

"The Gough Bunting is one of the most worrying because there is no other population in the world." —Dr Geoff Hilton, RSPB Scientists also suspect that the mice are also eating the eggs and chicks of the rare, ground-nesting Gough Bunting Rowettia goughensis, a small finch found no-where else in the world. Researchers think the finch (classified by BirdLife as Vulnerable) has been forced from the best nesting sites into less suitable upland areas. The Gough mouse is one of 2,900 non-native species damaging native wildlife on the 17 UK Overseas Territories and Crown Dependencies, a review by the Joint Nature Conservation Committee (JNCC) has found.

The RSPB has been awarded £62,000 by the UK government’s Overseas Territories Environment Programme to fund additional research on the Gough Island mice and a feasibility study of how best to deal with them. The grant will also pay for the assessment of a rat problem on Tristan Island, also a UK Overseas Territory, that unlike Gough has a human population and therefore pets and livestock as well.

4th July 2014