In total, Britain is home to 18 species of bat, the largest being the noctule, which weighs as much as four £1 coins,. The smallest, the pipistrelle, weighs as little as a 2p coin and is known to gobble up more than 500 insects in an hour. In fact, all bats rely on a healthy population of insects to keep them going, making them a very good indicator for local biodiversity. That’s why surveying for bats can be such a useful way to see the success of rewilding and other efforts to improve biodiversity.

Here in Avon we are rightly proud of our resident bat populations - the region is a stronghold for Greater and Lesser horseshoe bats, two of the UK’s rarest species – and we are currently undertaking several projects which aim to find out more about them. These little mammals have a characteristically fleshy nose that is shaped like a horseshoe. They can be told apart by size – a lesser horseshoe bat is about the size of a plum, while a greater horseshoe bat is equivalent to a small pear. They are truly fascinating – both to look at, and to learn about.

One of our main projects is centred on the Gordano Valley. A radio tracking study from the 1990s identified key flight corridors for these highly protected creatures to the Gordano Valley from their roosts in which they live and breed.  Exciting, yes – but beyond that, we have very little information about them. So our project, funded by the Bristol Avon Catchment Partnership, aiming to improve our understanding of how the bats use the landscape, could be genuinely revealing.

We have good reason to think the unique landscape of the Gordano Valley could be very important for our local bats. Linear features like tree-lined footpaths are vital to them, because they use them as corridors to navigate from one part of countryside to another. Familiar to anyone who knows the area are the long, straight rhynes or drainage ditches which criss-cross the landscape: the perfect linear feature for a bat keen to stay on track, you would think? That’s what we’re keen to find out.

Meanwhile, on our North Somerset Rewilding project, we’re supporting North Somerset Council’s bid to manage 25% of their public green space for wildlife. As part of that, we’re planning to train locals in the skills they’ll need to monitor bats themselves – a great chance for people living an and around Weston-super-Mare to experience the joy of tracking these amazing creatures for themselves.

Another hotbed of bat activity can be found in our Goblin Combe Reserve. This woodland site, south of Nailsea, is a place of contrasts, with airy grasslands set against the dark woodland below.

Its significance for greater and lesser horseshoe bats lies partly in its position, close to some of the UK’s most important maternity roost sites. Bats need a combination of woodland, scrubland and open cattle-grazed pasture, with plenty of dung beetles and other insects, and so we are actively thinning the woodland to improve the habitat, removing non-native conifers and bringing in livestock to graze the site.

All our efforts should help make these rare creatures a little more secure in our countryside. If you want to learn more about bats, or get involved with International Bat Night, why not download an International Bat Night Pack from the Bat Conservation Trust.  Inside you will find ideas on how to celebrate bats, help bat conservation, further resources and more. Most of all, take yourself outside this weekend and watch in wonder as these shadows of the night weave their magic.