One of the caves we undertake winter hibernation surveys at for the National Bat Monitoring Programme near Wetton Mill in the Manifold Valley has had no bats spotted in it during our checks for the last few years. To see if bats had stopped using the cave or whether we were just not coming across the bats in there we have deployed a bat detector this winter. It's not unusual to come across small numbers of bats in caves - due to all the crevices and parts of the cave we can't access, it's estimated that 1 in 10 bats are spotted during hibernation surveys.
Steve and Alan Roe from the Group deployed the detector in early December and placed the detector away from the entrance so that bats flying outside would not be recorded by the microphone and returned to change the batteries and down the data recorded so far just after Christmas. Out of the first 20 days, bat activity was recorded on 7 of those and all consisted of Myotis bat species so we now know that the cave is still being used by hibernating bats and that the mild weather means that bats are still moving around. The detector is still deployed in the cave and we'll be retrieving it during our hibernation survey in January so keep your eye on our news page for the full results of both the survey and the detector results.