An otter has astonished conservationists after completing a hazardous journey to reach a small island three miles out to sea.

Its arrival on Brownsman, one of the Farne Islands off Northumberland, was betrayed by tracks stretching about 60 metres along a muddy path. It is the first time that the mammal has been recorded on the islands.

The otter itself has yet to be spotted, but the agitated behaviour of gulls suggests that it is still using Brownsman and some of the other islands.

“It is staggering that an otter could survive the perilous journey out to the Farne Islands, especially Brownsman, which is a long way from the mainland,” David Steel, the National Trust head warden for the islands, said.

“We almost had to rub our eyes with disbelief when we discovered the tracks.”

Paul Chanin, an otter expert at the Mammal Society, said: “To find them so far off shore shows that they have a remarkable ability as navigators.”

Otters are found in coastal locations in Scotland, but they are more usually at home along freshwater rivers in England and Wales.

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