Islanders worried as evidence of a mouse is found

The islands of St Agnes and Gugh are joined by a sand bar at low tide and have been free of rodents for several years

Conservationists on an island 28 miles off the UK mainland are concerned after signs there may be a mouse there, potentially putting a colony of seabirds at risk.

Mice and rats have been eradicated from St Agnes in the Isles of Scilly, as part of measures to protect its "nationally significant population of storm petrels".

The Isles of Scilly Wildlife Trust said "probable" signs of a mouse including droppings and urine had been spotted, and suspects the creature was brought in within some animal feed.

The trust has been running a successful program with the RSPB and others to get rid of rodents on the islands for the past decade, which has led to the petrel population "bouncing back", it said.

Mice could be a risk to the population of storm petrels on St Agnes

Tony Whitehead, from the RSPB, said it had a "very well worked out response" which involved putting rodent poison in traps across the island and "then keep checking the traps".

He said if "mice do get a hold on the island" they would be likely to eat the eggs of birds like storms petrels and Manx shearwaters, putting populations at risk.

Mr Whitehead said a member of the community had spotted the mouse droppings last Thursday.

"The residents of the island have been brilliant and hugely supportive," he said.

The wildlife trust said signs had been put up across St Agnes to warn parents of young children and dog owners about traps.

St Agnes is one of five inhabited islands in the Isles of Scilly, and had a population of 85 recorded in the 2011 census.