“No I’m not an ‘escort’”- and other awkward scenarios for bat surveyors.

Natterer's bat found during hibernation survey

It’s dark, damp and reeks of fox dung. I’m in a disused train tunnel in north London, tagging along to a survey for hibernating bats. As I inch along I stick close to the walls keeping an eye out for the little critters squeezed in-between the brick crevices. I need to be mindful of train tracks, loose rubble and syringes. Lots of used syringes. The tunnels have been sealed for a while now so, although I doubt I’ll be stumbling into whoever left these, it does bring to light a small yet unfortunate risk with bat surveying; you wouldn’t want to stop and chat with some of the people you might find. Never mind the tunnels and graveyards, but even walking through a park at night can turn dodgy, especially if you’re in a city. Bumping into the unsettling ‘types’ was at the back of my mind when I first started looking for bats around London, but little did it occur to me that I would be the ‘type’ to unsettle others. After all bat workers lurk in bushes with funny equipment in the middle of the night, what could possibly go wrong?

Common pipistrelle

There’s a park just around the corner from my home which has a great site for spotting bats. In a dark corner under an oak tree, when the weather is nice and warm, you can see bats swarming; effortlessly flitting between the gnarled branches chasing midges and flies. Armed with my heterodyne detector, I can pick up on their ultrasonic calls as they’re converted into audible sounds helping me detect the presence and species of bats nearby. When I arrive the detector is silent save for the background static hiss. All of the sudden a series of quiet pops crackle from the speaker, a bat’s in the area. The pops get louder turning into rhythmic wet slaps, must be a pipistrelle species. I tune through the frequencies finding the pitch where the slaps are deepest to help me discern what species I’m listening to. 45khz, it’s a common pipistrelle! In a matter of minutes the air is seething with bats while my detector emits a symphony of pop, squeak, smack and fart sounds as the pipistrelles acoustically feel their way through the air searching for insects to eat.

Tempting as it may be to stand there oohing and aahing at this mesmerising display I need to be aware of the other people in the park. Fortunately for me I’m standing next to the exit so I’ve got an easy way out if I don’t like the look of anyone approaching. Not so fortunate for the hapless jogger, there’s a man standing in the shadows just off the path right next to their exit point. It’s hard enough not to be confused for a nut in the daytime when justifying to people why you spend your nights looking for bats. Trying to do the same with a wary stranger in the park isn’t any easier. But it isn’t just late night joggers and dog walkers that I’m making anxious. A man pulls up in a car just outside the exit and waits with the engine running. I doubt it’s an uber, unless ‘tuned up with spoilers’ is now a selectable option. “He’s probably just picking up a mate” I’m thinking. His ‘mate’ turns up and they talk for less than a minute. Whats this? No hugs, no kisses? It’s starting to look more like a transaction now. What kind of a person conducts business from their car outside a park at night I wonder? At what must be the worst possible timing, my detector screeches and whistles as it picks up some feedback. The two men stop talking and turn to me. Now my gear is looking more like recording equipment or even a radio. For the police perhaps? I take my queue and leave before things get more awkward.

Bat surveyor or police informant, you be the judge

Surveying with a heterodyne needn’t be such a conspicuous display; a pair of headphones can cut out the noise while the detector is hidden in a pocket. However, other survey techniques require the use of less subtle hardware, like say a large antenna for radio-tracking. Remember the documentary clips of tranquillised lions and wolves being fitted with radio collars? Same principle applies except on a smaller scale. You catch your bat, glue a tracking device to their back and let them go. Equipped with your antennae you can map out their movements before the device falls off them, by which point you’ve got an idea as to where the bat flies and roosts; an invaluable insight for a researcher or conservationist. One such specialist goes by the name of Sam, a spectacled, soft-spoken bat ecologist who’s as comfortable researching in a library as he is trekking through the jungle. The kind of breed who could recount a scientific paper while changing a jeep tyre. One night our bat worker was driving around for a radio-tracking session. One hand on the wheel the other holding the antenna out the window. After having done a few circuits, he decides to take a little nap in the car. Not much time passes until he’s rudely awoken by an elderly man brandishing bills and documents at him through the wind screen. “I pay for my TV license!”. Sam’s groggy and confused at first until he realises the strange man is gesticulating partly at the antenna that’s been propped up on the passenger seat. The concerned resident thinks he’s under surveillance! Who’d of thought the BBC employed such drastic fee collection tactics?

Being confused for an authority figure is one thing, getting the authorities called on you is another. I had the pleasure of working with a researcher named Alison; a friendly, ebullient post-doc, not the kind of person you’d consider a delinquent. But like Sam, her equipment didn’t do her any favours. She was carrying out bat surveys in Birmingham using full spectrum bat recorders; the mac daddy of bat recording equipment. These are designed to be left in the field unattended where they continuously record at all frequencies providing tonnes of high quality data for later analysis. They’re typically incased in secure boxes to protect them from the weather, vandals and thieves (human and animal alike). The issue with setting these recorders up in an urban environment, thieves aside, is that you’re lurking around neighbourhoods hiding nondescript boxes around the place. Imagine what that would look like to someone peering out of their window. As if getting the police called wasn’t bad enough, she was once approached, mid-survey, by someone hoping to solicit a service. How hiking boots, rain macs and head torches could be interpreted as sex worker attire is beyond me, but we’ve all got our kinks I suppose.

by Charlie Hearst, former intern at BCT and active London Bat Group member (You can find him on Twitter @CharlieHearst, Facebook, Instagram and follow his blog too)

(To check if you have a local bat group near you visit this page . If you are interested in taking part in our National Bat Monitoring Programme surveys do visit this page)

Into the Canopy

I have been involved with Swanton Novers NNR since I started as a volunteer with Natural England in 2008.  I subsequently secured a full time job as a warden for Natural England on sites throughout North and West Norfolk including Swanton Novers woods. Having since left Natural England to work as an Arboricultural Consultant for Norfolk Wildlife Services I’ve continued to volunteer for the Swanton Novers Woodland Project helping when I can.  I have an arboricultural background so the woods have always fascinated me and as the years have gone by they have opened up an interest in Ancient trees and landscape history as well as how species interact within these very special habitats.  In 2012/13 methodologies were drawn up and ideas started to come to fruition about a large scale monitoring program for the woods.  This mainly revolved around the bat communities and how they interact within the woods.  In the past bat transects and data collection focused on the easily accessible rides running throughout the woods.  This project was focusing on the interior of the compartments that were densely vegetated, hard to get to and little (if any) data had ever been collected - and it involved climbing large majestic Oak trees!  I jumped at the opportunity to be involved!

Due to time pressures and constraints the forty trees were chosen by Ecological consultants according to certain criteria  They had to be 50m from any ride side, spread throughout Great Wood and Little Wood and within different stand types and compartment classification.  A bracket was designed to secure the SM2+ recording devices to the trees and a bracket to take the canopy microphone secured on a southern aspect of the tree to record activity above the understorey.  Once everything was in place data collection could start and the logistical complications of the project would inevitably become apparent.

Firstly, finding a green tree in a very green wood with a piece of green cord dangling from the canopy presents its obvious difficulties.  Once the point tree had been found setting up the canopy microphones involved hoisting them into the canopy bracket.  With a careful flick of the wrist the microphone sat comfortably in its bracket sheltered from the elements by a funnel.  It didn’t take too long to learn that to retrieve the microphone the other end of the cord had to be tied securely on so a continuous loop was created.  Lesson learnt it was time to break out the climbing kit.  I always find it a privilege to see sights that others rarely get to view and looking across the canopy layer and down on the coppice compartments and over the field boundaries fills me with appreciation of scale in a wider landscape setting.  

Once the recording equipment has been set to record for two nights and the canopy and understorey microphones have been plugged in its time to retrace your steps back to the vehicle.  It’s funny how perception works inside dense undergrowth with no horizon or landmark to focus on – many times I thought I had been walking (stumbling) in a certain direction only to be utterly bemused and convinced that I had discovered a previously uncharted ride that is on no maps and in the middle of an unexplored compartment, only to find after a few steps of admiring this untouched (well-managed) ride that it was in fact one of the main rides in the woods.  After nursing my ego and the inevitable bramble rash it was time to find another 4 green trees in a green wood with a green cord hanging from a branch.   

As well as getting involved with the data collection for the fixed point surveys I have happily spent a few evenings walking transects around the woods.  This involved following a predetermined route that lasted about an hour with timed stops along the way.  There are 8 species of bat that use the woods and field edges for roosting and foraging so it’s a good place to get familiar with the different calls.  Even if it’s a quiet evening (bat wise) just experiencing the woods at dusk is a joy.  Many badgers call Swanton Novers Great Wood their home, supermarket and meeting place.  Often they’ll cross your path with the familiar gentle jog, have a cursory glance in your direction and be off again.  

Jim Allitt now works for Norfolk Wildlife Services as an Arboricultural Consultant and if you would like more information about the project and how it was set up then please contact Sonia at srevely@bats.org.uk,  so she can forward 

by Jim Allitt

My Communications Internship at the Bat Conservation Trust

I have always had a keen interest in nature and wildlife. Growing up my interest in the beauty of our natural landscape, its wildlife and its preservation has continued to grow. I spent a great deal of time at university studying and researching the effects of conservation efforts in the United States and in the UK. During my final year at university I looked into the effects of increased population and over development in the USA during the Nineteenth and Twentieth Centuries. I focused on the consequences met such as the sudden decreased population of animals like the Grey Wolf and American Bison. In addition I studied individuals that provoked the preservation of a dying environment such as John Muir and Theodore Roosevelt. My hope is to continue my passion for the protection of our environment by developing and shaping my career through charities such at BCT.

Although I was unable to find the perfect role within a conservation charity after graduating, I was not deterred. I decided to look into internships within conservation organisations (I hadn’t previously ventured down the internship pathway). I stumbled across BCT’s Communications Internship and decided the role sounded fantastic – a communications role that dabbled in events and fundraising, and within conservation - Perfect! After applying so eagerly (approximately 3 weeks before the application deadline) and not hearing anything back since the confirmation reply email, I had come to the conclusion that sadly nothing was to come of it, until I had a sudden call offering an interview! I was ecstatic! This was my big break, to get a foot in the door, and a step in the right direction. After meeting the team and finding out more about the organisation I was hooked, and when, to my surprise, they offered me the role I couldn’t believe it, I said yes, of course!

The long-eared bats I met during my visit to Jenny Clark's Bat Hospital

I found out straight away that the BCT team were amazing, full of kind, intelligent people dedicated and passionate about protecting bats. The work they do here is invaluable to the protection of bats. From the National Bat Monitoring Programme to the Helpline, Mitigation to Communications, together they inform and educate so many on the importance of bat conservation. I have met some incredibly influential bat enthusiasts who have dedicated so much of their lives to protecting this fascinating species.

A highlight of my time at BCT has to be my visit to Jenny Clarks bat hospital. We met a variety of bat species including all three Pipistrelles: Common, Soprano and Nathusius, Serotine, Noctule, grey and brown Long Eared, Natterers, Brandts, Whiskered, Daubentons and Bechsteins. It was also where I discovered how incredibly beautiful the brown and grey long eared bats were! Jenny is an incredibly devoted woman, whose passion and dedication is outstanding.

Part of BCT's exhibition at Gardener's World Live

Another highlight of my time at BCT was definitely Gardeners World Live. Not only did I get to meet more dedicated bat enthusiasts who volunteered with us, I also aided in spreading the good word of bats and how important they are to the environment. It was incredible to see how many people were unaware of the importance of bats, but how many of them were truly interested in making a difference to our environment by encouraging bats into their gardens. It was a brilliant whirl wind experience and one I won’t forget!


I have learnt so much in the past 3 months at BCT. I have gained so much experience from working with such a dedicated team. I can safely say that I have thoroughly enjoyed my time here and hope that our paths cross again in the future!



Emma Cross

Monitoring Bats – An Exciting Opportunity

Spring has fully arrived and I’m sure you are enjoying those warmer temperatures!  It’s not only us though who get more active when the conditions change.  You may recall in previous issues we discovered how seasonality can affect bat behaviour, with churches providing a safe haven at those most vulnerable times.  In winter bats hibernate; but as night temperatures rise above 10^OC, they will wake up and take advantage of increased insect activity.  They start emerging from April to May, and when they do, it offers an exciting opportunity to get involved in recording any you see flying over any space.

Illustration by Liz Vinson

Bats have unfortunately become an endangered species over past decades, with major population declines.  If you see a bat, its great news and hopefully a positive sign that they are recovering.  It can be hard to know this for certain, but that is where submitting any sightings can help.  At the Bat Conservation Trust (BCT), there is a National Bat Monitoring Programme (NBMP).  NBMP has been calculating population trends for over 20 years, with all records submitted by volunteers.  In fact, it’s all done on a voluntary basis and there are over a 1,000 people throughout the UK who help each year in carrying out bat surveys.  Some can be challenging, but the ‘Sunset/Sunrise’ survey is ideal for anyone.  It simply involves heading out at dusk or dawn, (or both) and spending an hour looking for bats flying overhead.  This can be done anytime from April to September; record the time, temperature and number of bats seen, and then send through the results.  

I’ve now left BCT, having taken up a Sustainability Project Coordinator post at Broomfield Hospital in Chelmsford.  The hospital does have a bat roost, and I am certainly still passionate about the bat world.  If you’d like to get involved with the NBMP, please do email BCT’s dedicated team nbmp@bats.org.uk or look at their website www.bats.org.uk/pages/nbmp.html

Happy monitoring!

David Jackson