As previously reported, the presence of grey long-eared bats was found in DNA testing from Friends of St Peter’s Church inside the derelict site.

According to records, the grey long-eared bat is very rare, with only around 1,000 found in the UK. Locals also say this could be the first recorded evidence of the species on Portland.

Nick Tomlinson of the Dorset Bat Group explained how important this discovery is and has theorised what the species could have been doing there.

He said: “Grey Long-eared bats are very rare species in the UK, restricted to the south of England, and Dorset is a key county for the species. 

“They normally hunt over unimproved grasslands, river valleys and woodlands, so recording one on Portland is amazing, although, of course, we don’t know what it was doing there.”

“The Dorset Bat Group has been researching a phenomenon called Autumn Swarming for some years now.  It is, in effect, speed dating for bats, with bats flying from as far away as 10km or 20km to visit a swarming site, and then flying back the same night, and all to find a mate; not bad for an animal that flies only a few km from home on a typical feeding flight for the rest of the year.

“Grey Long-eared Bats are so rare that we are still learning so much about them and we don’t know, for sure, if they visit these swarming sites, but our data from elsewhere hints that they might.  We do know, for sure, that some other rare woodland bats, such as Bechstein’s Bats, do visit the island to swarm, so it is possible this Grey Long-eared Bat was ‘looking for love’.  Only more research will help us know for sure.”

According to the Bat Conservation Trust, the species is a very rare medium sized bat, and is one of only two long-eared species in the UK. They are known to eat months, flies and small beetles with numbers quite low.

In England, the species are restricted to a few colonies in Sussex, Hampshire, the Isle of Wight, Dorset, Devon and Somerset.

The trust says there are no specific conservation management plans for the bat despite the species rarity, due to both a lack of information on its behaviour and ecological requirements.