Bat Success!

February 18, 2023 by Mark Knight

As many of you will know, the TTTV team has been repurposing WWII pillboxes for wildlife across the project area; in particular, we have been converting a number of them for bat hibernacula (where bats can hibernate through the winter), or for swallow or other wild bird nesting sites.  With help from our team and lots of our volunteers we have now converted seven pillboxes.  The main thing to consider when trying to include places for bats, birds or any other wildlife to breed or hibernate is the best way to keep people out.  Most people are just very interested, which is wonderful, but wild animals invariably value their privacy.


To try and get a peek into their private lives (and to see if our conversions are working) we placed trail cameras into five of our converted pillboxes.  The results were almost immediate and we’re very pleased to be able to announce that bats are definitely using the pillboxes, and it looks like they may even be moving in permanently.  One of our trail cameras failed, so we have no evidence from that pillbox but the other four all showed bats flying through them and one showed definite evidence of interest in moving in.   The bat hibernacula conversion involves blocking up the loophole windows and leaving a letterbox sized slit for the bats to use as an entrance.  The other conversions are for wild bird nest sites or summer roosting for bats – in this case we put in nesting shelves and fleece or hessian sacking for bats to hang in.

This lovely footage of a brown long-eared bat emerging from behind the roosting panel we fitted was very exciting to see!

In both conversion types we fix a lockable steel-plated door to keep people out, so that the bats or birds can get on with things without disturbance.

Our trail camera evidence is quite dramatic.  Birds use the open pillbox types for nesting or for foraging for insects.  We’ve had tawny and barn owls visiting the pillboxes and resting during daylight hours, although not yet nesting there themselves.  Even more excitingly, we’ve had video footage of bats hanging upside down from the roof, crawling on the walls, crawling in the hessian, flying through the pillboxes and perhaps even moving in for the winter.  The trail camera footage of the bats seems to show brown long-eared bats but when they’re flying they’re so fast moving that it’s difficult to say for sure what species they are.  The activity also makes sense with what we know of brown long-eared bats, in that they like to have a bit of a warm up before they go hunting for the evening, in this case by stretching their wings and flying around inside the pillboxes.

The team were all thrilled to see this barn owl having a well-earned rest.

Mea culpa!  I forgot to reset the date and time when I replaced the camera batteries last time I put the trail cameras into the pillboxes, so please ignore the video date stamps.  Both video clips date to last September or October.

Enjoy the short video clips and images, I hope you’re as excited about this news as we are.   All of the TTTV team are looking forward to being able to update you with future information, although now that bats seem to have moved in we have to change our approach.  To enter a known or possible bat hibernacula without a licence is an offence so we now have to bring in trained specialists to enter the pillboxes for us.  This is, ultimately, good news as it shows that our conversions are working well for wildlife.


We’ll keep you posted, fingers crossed for future good news from the bat cave…


Dr Mark Knight

Cultural Heritage Officer

Transforming The Trent Valley