27th January 2025
The last known individual of the greater mouse-eared bat was a male, who was nicknamed the loneliest bat in Britain. To everyone’s surprise he was joined by a second bat in 2023 (its sex and breeding condition were unknown), after 20 years of spending winters hibernating alone in a secret tunnel in Sussex.
Then last week not one, but two new individuals were found! Keep reading to find out more.
Possible mate for Britain’s loneliest bat
Female greater mouse-eared bat after ringing
Every year, volunteers and members of bat groups carry out hibernation surveys in known and potential bat roosts so we can understand how UK bat populations are doing.
Since the discovery of a second greater mouse-eared bat in 2023, members of Sussex Bat Group have been eager to find if this was the start of a new colony. But during the 2024 winter season, neither of the two bats were found. Did the bats decide to roost elsewhere in the region, or did they leave the UK altogether?
On the 18 January 2025 hope was, however, restored! During a hibernation survey, members of the Sussex Bat Group found a greater mouse-eared bat. After closer examination (all performed under a licence) they realised this wasn’t our known resident male; it was in fact an adult breeding female.
Daniel Whitby, bat ecologist and founder of Bat Conservation and Research Unit explained: “Having surveyed this area persistently since the first discovery of a greater mouse-eared in 2002, the finding of a female is rewarding and a remarkable discovery which brings huge hope for this species.”
Daniel Hargreaves, Bat Programme Manager for Vincent Wildlife Trust, said: “Finding a female greater mouse-eared bat in Britain is fantastic news, and I feel privileged to have witnessed it firsthand. In a sad twist of fate, the lonely male who hung around since 2002 hasn’t been seen since 2023 — but we can only hope further individuals are discovered and that a viable population is formed.”
The greater mouse-eared bat returns to Kent
Greater mouse-eared bat discovered in Kent. (c) Caitlin Laver
As if the exciting news of a female greater mouse-eared bat wasn’t enough, last week a new individual was rediscovered in Kent for the first time in over 40 years! This new discovery at Dover Castle brings hope that at last we could see this species begin to re-establish itself after the last colony was lost in the 90’s.
The bat was found by South East Ecology’s principal ecologist, Claire Munn, who has been monitoring heritage sites for bats in Dover since 2018, along with members of Kent Bat Group. She said the area has excellent swarming sites where enthusiasts enjoy watching several rare bat species, including greater and lesser horseshoes and Myotis species.
She adds, “I was leading a team of fellow volunteers for our regular hibernation surveys. We were gobsmacked to find a very large bat, which looked somewhat like a Natterer’s that had overdone it at the gym and taken too many steroids! ID books at the ready, we surmised it was probably a greater mouse-eared bat. We have since had that confirmed.”
“It could well be that the great mouse-eared bat was attracted to the site by the other swarming bats,” she said. “The discovery of the greater and lesser horseshoe bats, and now an individual of the UK’s rarest bat, the greater mouse-eared, shows just how important these coastal heritage sites are. It’s fascinating to think that I may be looking at a bat descended from a bat that WWII soldiers were looking at, or indeed that Henry VIII may have seen!”
Embracing natural heritage and bat conservation
Both of these finds perfectly illustrate how important it is to preserve historic sites and the habitats around them. They provide refuge for a range of species and have the perfect conditions bats need to hibernate; stable and undisturbed.
Claire from Kent says, “The interest the local public have in wildlife and historic sites is strong. Bat conservation and heritage conservation in Dover are so intrinsically linked and I’m very privileged to be able to help the owners, stewards and managers of these sites work in a way that embraces and conserves both the natural and human history, and with a joined up approach across the wider Dover area; you can’t disentangle the use of these structures by both bats and people for many decades, and indeed hundreds of years.”
Over in Sussex Daniel Hargreaves explains, “During the last two years, we have spearheaded a project in Sussex, funded by Natural England’s Species Recovery Team, to create and enhance roosts for some of the rarest bats in Britain, including the greater mouse-eared bat. It's vital that we protect what we have but also create space for what we’ve lost. By providing suitable roosts, restoring habitats and reducing anthropogenic threats such as artificial light and noise, this species might just stand a chance of recovering.”
Female greater mouse-eared bat
The greater mouse-eared bat is found across most of Europe, and often roosts in caves, mines and cultural buildings. It’s possible the bat migrated over here from the continent, but it’s also possible it’s been living here secretly for a long time and has only just been discovered!
It forages in forest clearings and semi open areas, mainly hunting ground beetles. It can live for around 25 years, although its average life span is 3 - 5 years. You can learn more about the greater mouse-eared bat here.
Kit Stoner, CEO of the Bat Conservation Trust said: “This exciting discovery highlights the vital work of our wonderful citizen science bat conservation volunteers and the important work of bat groups, collecting important information that feeds into BCT’s National Bat Monitoring Programme. Let’s hope with more monitoring we can continue to learn about this species. I hope to see this species re-establishing a population and a new beginning in England.”
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