Lets Go Bats

Some of the bats caught at Poole's Cavern during a recent survey by Derbyshire Bat Conservation Group.

Rather topically with Halloween just around the corner, we recently had a bat survey conducted in Poole’s Cavern by Derbyshire Bat Conservation Group. The group were hoping to record swarming activity. This involves of bats from a widespread geographic area, visiting an underground site and chasing each other in and around the entrance.
The reason why bats swarm during the autumn is not fully understood, but probably allows them to check out hibernation sites and bring males and females from a wide area together to enable mating opportunities and therefore increasing the genetic mixing between colonies.
Steve Roe, Events Manager for Derbyshire Bat Conservation Group explained that although no swarming activity had been recorded; all bats caught were male adults in breeding condition. Steve explained further that “Far more male bats are caught during swarming surveys and it may be possible that they were males checking out the site to see if any swarming was taking place or it could just be that they are using the cavern as a roosting site. It is probably a combination of both, however four species in a single night is still a great result and clearly the site is important for the local bat population.”

It is believed that the reason why more male bats tend to be found during the autumn swarming events is that once mated a female will no longer participate, where as the males will continue to swarm to increase the chance that their genes are selected by mating with more than one female.

In all ten bats were caught in total from four different species; 5 brown long-eared’s, 2 Daubenton’s, 2 Natterer’s, and 1 whiskered.

Our thanks to Derbyshire Bat Conservation Group for carrying out the survey and to Steve Roe for letting us use his photos.