A rare species of bat has been discovered roosting at a site in East Devon.

Exeter-based company Acorn Ecology shared photographs of a grey long-eared bat, of which there are less than 3,000 in the country. Staff carried out biometric tests on droppings below the roosting mammals to confirm it was the rare species and not the more common brown long-eared bat.

Colin Bonfield, senior ecologist, said: “The bat appears to be using the building as an occasional day roost and a regular night roost and is probably associated with a larger colony somewhere in the locality.

“The South West is a stronghold for bat species and 17 species have been recorded in Devon. In my opinion, the presence of grey long-eared bats in Devon is highly linked to lower levels of light pollution as long-eared bats are one of several light averse species present in Devon.

“Other very important factors include currently favourable agricultural practises, suitably diverse foraging habitat and the presence of suitably managed woodlands and the presence of old buildings and structures that provide suitable roosts.”

The company carries out ecological surveys and impact assessments in support of planning applications. It could not disclose the exact location of the bats.