5 years ago on a university field trip to Mexico, my course-mates and I were briefed on the itinerary for the next few days. Knowing there would be some kind of treat to reward us for all the full-on fieldwork, we waited eagerly to find out what it would be, only to hear
“In previous years, we have taken the students to see manatees in a lagoon near-by, however this year we will instead be going to a bat cave at dusk to watch them emerge!”
At this point, I was fairly indifferent to bats, and all I, and many of my course-mates, could think were the lost manatees.

Thankfully, my disappointment was short lived and as it turns out, totally unnecessary. We visited the Calakmul Bat Cave and it turned out to be the top nature experience of my life! We crouched amongst the trees at the edge of this vast cavern, sunk into the ground, and waited. Millions (literally – around 4 million) of bats began to swirl up around the edges of the cave like a tornado, dispersing over the trees to find their first meal of the night (if you search the cave on YouTube you can get an idea of the awe-inspiring sight).

It was a spectacle I will never forget, which sparked my interest in and love for bats. Although none here are as big as the tropical bats found in Mexico, the UK is actually home to 18 species of bat, meaning they make up nearly a quarter of UK mammals[1]. Each have their own characteristics such as long ears, odd-shaped noses or big hairy feet - all adaptations for catching different types of prey in unique ways.

I think the thing that draws me to bats is their elusive nature and how because of this, they are generally poorly understood. They aren’t easy to study as part of a casual hobby, which is why I feel particularly privileged to have been given the opportunity to enter their night-time world and study them with the help of a bat detector.

Contrary to popular belief, bats are not blind. In the dark they do need a clever strategy to catch prey that they can’t physically see. To do this, bats echolocate, which means they use sound waves to detect their prey whilst on the wing (other species also do this, including dolphins). The sounds they create are at a frequency much higher than the range detectable by the human ear, however bat detectors convert this sound to something audible to us. Although it is fairly common to see bats in both cities and rural areas as dusk settles, hearing a bat through a detector adds another level to the experience. They even allow us to hear the exact moment a bat hones in on an insect and catches it!

I have been lucky to have lived in various places in the south west of England, allowing me to encounter a wide range of species including the highly protected greater horseshoe bat Rhinolophus ferrumequinum. These bats, along with the lesser-horseshoe Rhinolophus hipposideros, produce the most unique sound which I liken to a little alien. This is a video I captured during an emergence survey for greater horseshoe bats as part of the National Bat Monitoring Programme.

Now living in Hampshire for my current role, it has been exciting to learn from my experienced colleagues, and encounter new species that I haven't come across elsewhere. Part of my role as a trainee ecologist has involved scrolling through sonograms (essentially, sound images) of bat calls, which allows us to identify bats that may have been too quiet or fast to hear or identify in the field. By looking at the various aspects of the calls such as frequency and duration, we can identify most bats to species level. One which has a particularly unique call is the barbastelle barbastella barbastellus. It has been exciting to “tick off” a new species for me, particularly as the barbastelle is a rare bat (there is likely only around 5000 individuals in the UK[2]), only found around deciduous woodland in the south of England and Wales.

What do bats do for us?

Bats, as well as being unexpectedly cute and charismatic, are fantastic indicators of how an ecosystem is functioning. Because of the habitats, prey and conditions they need to survive, gaining an insight into bat activity in an area can tell us a lot about a number of other things. For example, all UK bats are insectivores, and a healthy population of bats means there is a good biomass of invertebrates in that area, and we all know that invertebrates are important for a whole host of things such as pollination and decomposition. And those pesky midges and mosquitoes we all hate? Bats LOVE ‘em!

This all means that work to conserve and protect bats and their habitats ensures a range of other species are looked after, and whole ecosystems are preserved and enhanced.

Inspired? Want to get involved? Here’s how:

• Join a local Bat Group – they host events such as bat walks and carry out monitoring of local sites with the help of dedicated volunteers.
• Take part in the National Bat Monitoring Programme – this is great for people of all abilities with varying amounts of time to spare.
• Get a bat detector and explore your local area (with a buddy, where it’s safe) or even just listen in your back garden. Although not the cheapest bit of kit, there are basic models available for £60-£80 which will last a long time. Both local groups and the NBMP will also loan detectors to volunteers for taking part in walks or their surveys, and some local libraries will also loan them out.

[1] https://www.bats.org.uk/about-bats/what-are-bats/uk-bats

[2] https://www.woodlandtrust.org.uk/trees-woods-and-wildlife/animals/mamma…