One of Britain’s and northern Europe’s rarest and most elusive mammals has been discovered living in the east of England for the first time in 115 years.

The return to Kent of the greater horseshoe bat has delighted and astounded conservationists, who are now examining whether climate change is shifting the species’ range. The bat is normally found only in Wales and the west of England.

This secretive, buff-coloured, creature (Rhinolophus ferrumequinum) is one of Britain’s biggest bats. It frequently evades and challenges pursuers, fluttering unseen through shadows and hiding underground in caves, tunnels and occasionally buildings.

The animal hunts and navigates by screaming out high-frequency echolocation whistles through flaps on its horseshoe-shaped noseleaf, but the calls are beyond the human hearing range. The bat often navigates in silence or changes the shape, width and direction of its sonic beam, along with the intensity of the pulse, which means ecologists searching for it can easily miss it.

The creature’s distinctive, alien-like, ultrasonic warbling signals were recorded at two locations near the coast during May and June by two separate teams of bat ecologists.

Joe Nunez-Mino, spokesperson for the Bat Conservation Trust, confirmed that the unusual recordings had been verified by national experts. “It is possible that an individual bat was blown off course or has travelled over from France, or that a bat has dispersed across the UK from strongholds in the west of England or Wales.

“It is also possible that the species is now able to expand its range into Kent due to climatic changes. The habitats in the area that the recordings were made are not dissimilar to those in its western strongholds.”

Facebook Twitter Pinterest Close-up of a greater horseshoe bat’s face Photograph: Daniel Hargreaves/Bat Conservation Trust

No one has yet found the bats’ roost, and it’s not known whether this is a breeding population or how they arrived. These bats do not typically venture beyond a range of about three to 20 miles from a roost, and Britain’s 12 known isolated greater horseshoe colonies and 35 breeding roosts are all much further west.

The news is a further sign that the greater horseshoe’s fortunes are turning round. Britain has lost more than 90% of this bat’s population and half its range over the last 100 years; numbers have fallen from an estimated 300,000 individuals. However, the Mammal Society says the animal’s numbers have roughly doubled in the last 10 years, from an estimated 6,500 to about 13,000 individuals.

Recent evidence suggests climate change is driving up the numbers of greater horseshoes, bringing more insects in warmer springs, earlier bat births, spring rainfall and better temperatures when the animals emerge from hibernation.

The Bat Conservation Trust says good farm and landscape management can mean huge potential for greater horseshoes. They need woodland, a lack of light pollution, pesticide-free grazed pasture with chemical-free dung harbouring dung beetles, as well as moths, cockchafers and flies, plus tall continuous hedgerows that are not trimmed for up to 10 years.