After a decline in their population size throughout the 70’s and 80’s, the greater mouse-eared bat was declared extinct in the UK by the 90’s. However, in 2012, much to everyone’s surprise, a single greater mouse-eared bat was discovered hibernating in an underground tunnel in Sussex. Given the importance of the finding, the bat has been monitored ever since. Babec Director Tim Buckland, who has been helping Sussex Bat Group monitor hibernation sites for several years, recalls his experience on a recent monitoring check for the greater mouse-eared bat.

The entrance to the disused tunnel, the location of which is now a closely guarded secret, has since been sealed off to members of the public. It takes three of us to loosen the deadbolt and finally prise open the door. We’re quickly engulfed in darkness so it’s torches on and the hunt begins…

Bats in temperate latitudes need quiet and cool places where they can slow their metabolism and become dormant over winter, so hibernation sites are frequently found in disused underground sites, such as caves, mines and tunnels. For those not lucky enough to have been involved in bat hibernation checks before, it involves painstakingly checking tiny crevices and gaps for bats using nothing more than a torch and binoculars. When hibernating bats are located, pinpointing the species can be a challenge even for experts. It’s often just tiny clues like the shape of the tips of the ears or the size of the feet that give it away.