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Friday, 26 March 2021

The bat-worker’s library Part 1 - The essentials

I was recently asked to recommend some books on bats for someone starting out on their bat-working career. It created an interesting conundrum: you can only buy so many books at a time (though I confess I’m a massive bibliophile and that doesn’t apply to me), so should I focus on the books which fascinate and inspire, or on the ones which contain essential information? Tricky. So, I’ve decided to do both.

Here is my essential library of bat-worker books: the ten essential books that I hope somebody would point me towards if I were starting off with bats and intending to take it seriously. I’ll write another post soon, with my list of books that get me off the couch and fired up to look for bats.

The bat-worker’s manual (3rd edition) Mitchell-Jones & McLeish 2004

If bats were cars, this would be the book you find in the glove-box, to tell you how to make all the gadgets work. Although due an update, it is still an excellent and fairly comprehensive manual, filled with practical reference information essential for anyone involved in bat conservation. If you're working towards your bat license, this is your bed-time reading. If budget is an issue you can download it free of charge from the JNCC website.

Bat surveys for professional ecologists good practice guidelines (3rd edition) Collins, 2016

I'm not a huge fan of how the content of this book is presented, but for anyone who works or hopes to work with bats in ecological consultancy it is an essential reference for the appropriate methods to carry out effective and compliant surveys. If only more people would recognise that it contains guidelines and not rules! Each edition has improved and built on the success of the previous one and I'm looking forward to seeing how the 2022 4th edition turns out.

Bats of Britain and Europe Dietz & Kiefer, 2018

This chunky paperback has a permanent place in my bat handling bag. All the identification info. you could possibly need, in a portbale format, including the best key to bats I've ever come across. If you're handling bats at all, this is an essential field guide.

Bats of Britain, Europe and north-west Africa Dietz, von Helverson & Nill, 2007

A massive hardback with comprehensive information on bat species. I tend to think of this as the expanded version of 'Bats of Britain and Europe.' Think Baby Stace and Scary Stace, if you know your botany field guides! If I could only have one bat book, this is the one I would choose.

Bat roosts in trees Andrews, 2018

Henry Andrews was in my MSc group and even then it was obvious he wasn't going to let go of this subject until he'd worried it to death, like an angry terrier. Henry is responsible for a massive step-change in our understanding of tree-roosting bats and their roosts. It's a very useable field guide to tree roosts and how to survey for them.

British bat calls Russ, 2019

John Russ' book was a long time coming, but worth the wait. Bat call analysis is a core skill for anyone surveying for bats and John's book is the central guide to the characteristics of the calls of each species. It has gaps and weaknesses, but they are down to gaps in research, rather than to Jon. I understand he may be working on a new version. Bring it on.

Social calls of the bats of Britain and Ireland Middleton, Froud and French, 2014

When Neil Middleton and I collaborated on a bat reserach project on the central lowland canals back in the early noughties, it was apparent he had a book or two in him. Together with Andrew Froud and Keith French, Neil has brought together a wide spread of research into bat social calls and given them widely-understood classifications, with clear information about each. A very useful companion to Jon Russ' book.

Atlas of the mammals of Great Britain and Northern Ireland Crawley, et al, 2020

The result of a huge piece of research, led by the Mammal Society, this book has the most accurate distribution maps for each UK mammal species currently available. When it was published last year it represented a huge step forward - previous bat distribution information was woefully out of date and didn't reflect the advances achieved by modern bat detectors. Plus it has all the other UK mammal species too!

Designing for biodiversity – a technical guide for new and existing buildings (2nd edition) Gunnell, Murphy & WIlliams, 2013

I've lost count of the number of times I have pointed architects and developers towards this book. Co-published by the Bat Conservation Trust and the Royal Institute of British Architects, it contains ideas and technical guidance for building bat boxes and bird boxes into a wide range of new-build structures.

Bats in traditional buildings Howard & Richardson, 2009

This is effectively the building restoration companion to 'Designing for Biodiversity'. Co-published by English Heritage, The National Trust and Natural England, with input from the Bat Conservation Trust, it is again the book that I point many clients towards. It brings together a great deal of useful information on how to take bats into account when managing, restoring and repairing historic buildings.

As soon as I get time I'll write about the bat books that inspire me. Watch this space!

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Monday, 22 March 2021

An under-rated bat detector - the Peersonic RPA3

I first bought a Peersonic bat detector in 2014. Having tried it out I rapidly bought a further seven and I’ve just ordered another four. So what is it about this detector that makes me part with money so willingly, in a world which is increasingly cluttered with bat detector models and (in the case of at least one manufacturer) some quite vocal marketing?

Peersonic RPA3 bat detector

When you first pick up a Peersonic RPA3 (the current model) it doesn’t scream “Buy me, use me, I’m a really good detector.” In fact, it looks unprepossessing and, if appearance is a factor in your choice of machine you’ll probably walk away and look at some of the many shiny, well-marketed options available from Anabat, Wildlife Acoustics or Elekon.

Bats, as well as occupying a lot of my spare time are also my profession, so, whilst professional image is important, functionality is what really floats my boat when we’re buying sets of detectors for our team to use. Do we want fancy colours or gadgets? No. Do we want visible sonograms to distract our team members from where we really need them to be focussing - the building they’re surveying? Of course not. So for our purposes the bland cream case of the RPA3 is absolutely fine. (By the way, our supervising ecologists are mobile around our survey sites with machines which DO show live sonograms).

So what does it do? Well, it records full-spectrum WAV sound, whilst allowing you to listen to frequency division or tunable heterodyne output. The optional date and timestamp module does exactly what it says on the tin. Recording is to an SD card, mounted internally and the unit is powered by three AA batteries and we’ve seen no evidence of it being power-hungry.

The screen is small, but displays sufficient information to be useful. It displays the menu items as you scroll through using a rotary knob on the side (which also doubles as the heterodyne tuning control) and a button on each side for enter and back. When in use it displays the peak frequency of the sounds currently heard – useful for on-the-hoof Pipistrelle species ID, it also gives an amplitude reading in dB, which I don’t find too useful, though the matching bar-graph is handy. You can choose to record bat passes manually or automatically and in the latter mode the screen is blocked for a moment or two whilst the machine finishes the recording, which can be mildly irritating.

You’ve got to be tough to do bat surveys north of the border – an RPA3 in action, with hundreds of hungry Scottish midges.

In use we’ve found the detector to be as sensitive as most other detectors currently available and more so than some. It fits nicely into the hand, depending I guess, on the size of your hands. The case has a wrist-strap (yet ours still get dropped occasionally. Go figure.) and a threaded hole on the rear, which allows tripod mounting, if you’re so inclined (Peersonic also make a static monitoring version, which utilises this).

The ability to switch in use between FD and Het. is useful, especially when supported by the peak frequency indication. We tend to use FD mostly, but when Pipistrelle foraging activity is high, the ability to switch to Het, and listen for later-emerging species by tuning down to around 35-40kHz is handy (possibly less so in areas with a broader species assemblage than Scotland). As the machine records in full-spectrum, regardless of what mode you are listening in, this gives a measure of security from missing anything inportant.

One possible weakness, depending on how you use your detector is that the RPA3 lacks a loudspeaker, so you use headphones. Purists will tell you (rightly) that this is the best way to listen to bat calls, if you want to hear them clearly. However, I’m not a purist and I’m not keen on random, possibly dodgy people being able to sneak up behind our surveyors at night. We also like them to be able to hear their two-way radios, so headphones don’t work well for us. And this is where another factor comes into play. Peersonic is a UK-based company, run by engineer, Peter Flory, who isn’t just willing to help with random requests, he positively seems to relish them. So our machines were modified by Peter to work with mono earpieces, rather than stereo headphones.

We have now racked up several thousand surveyor hours using these machines and we’ve really only had three problems, all of which were easily rectified. Firstly, if a machine is dropped (which you really shouldn’t do, but hey, it’s dark, it’s cold and we’re tired…) it will sometimes stop working. However, the fix for this is easy, as it is simply caused by the internal SD card being dislodged. Undo two screws, pop it back in and you’re back in action. We’ve had a couple of machines ‘skipping’, when moving through the menus. This turns out to be caused by the nut on the rotary knob being too tight and slackening it slightly resolved the problem.

One of our survey kits, ready for use with personal radios, torches, batteries and four RPA3 detectors

The only other issue we’ve had was a case cracking slightly around the battery compartment. The problem here was that the battery holder grips the batteries tightly, so we tend to lever out the AA batteries, putting a strain on the case. One of our cases developed some cracks after this had been done a few hundred times and had to be replaced. It’s the only one though and at about £40 it didn’t exactly break the bank, which raises another angle on Peersonic. In an age of built-in redundancy and frequent upgrades Peter assures me that the RPA3 has been designed to be future-proofed and repairable.

So to sum up, the Peersonic RPA3 is a sensitive and effective bat detector, doing everything you need for commercial bat surveys and, but I’ve saved one factor to the end. The price: At the time of writing, Peersonic retail the standard RPA3 at just £245 + VAT and carriage. I’ve told Peter he could and should double that price, but he’s committed to making the machine freely available - for bat group or casual use this is a lot of bat detector for an affordable price. So whatever you do, don’t overlook Peersonic, just because there are shinier machines out there, made by companies with bigger marketing budgets.

Peersonic website:

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Thursday, 18 March 2021

Bat surveys - where odd stuff is normal

Bat surveys are one of the few things in life where one gets the chance to poke about in all sorts of unusual buildings, sometimes occupied, sometimes derelict and sometimes ruined, but always showing evidence of what a strange species human beings are. Here are a few of my favourites.

I never found out why this disused South Lanarkshire timber factory had creepy dolls scattered inside it.

The discovery of this decapitated rabbit on a tree-stump was made especially disturbing as it was outside the entrance to a disused Dundee asylum.

Staring at a building during bat emergence surveys requires tenacity at the best of times, but this frankly repulsive mural added an extra challenge for our survey team.

I have no idea who Gary is or what he really looks like, but as this Midlothian warehouse has now been demolished it's nice that his colleagues' caring views can be immortalised here.

This derelict building in Argyll had clearly been visited by a graffiti artist with psychic powers - these two pciture are a perfect prediction of our arrival.

In the dim light of a derelict woollen mill this heap of tailor’s dummies made my heart jump for a moment!

It’s good when clients pay attention to my advice about not disturbing a known bat roost…

It looked like the kids at this Dundee Primary School knew we were coming!

This derelict Glasgow hospital clearly hadn’t been somebody’s favourite place to work.

We’ve had a few sunset surveys with noisy Herring Gull colonies, but I’m not sure what this person’s issue was…

I don’t know who Shifty is or was, but I wouldn’t like to meet him on a dark night.

I could fill dozens of posts with the amazing graffiti at Polphail, Argyll, but this one in my favourite. Sadly it’s demolished now, replaced by two bat houses.

It’s great when a client really gets excited about the work we do…

Ok, I confess – this was us. There was paint left in the can used to mark 52 roosts we had found on this huge site and we couldn’t resist!

Profound graffiti in this derelict hospital in St. Andrews.

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Monday, 8 March 2021

Ignore the gods of bat-work at your peril.


It's been a while since I wrote a blog post, but I am increasingly worried that many-up-and coming ecologists are unaware of a vitally important aspect of professional bat-work, which I need to correct.

I’ve never been particularly superstitious, but when I realise that the bat survey season is beginning to loom I tend to reach for the cuddly toy bat which sits beside my desk, and give it’s belly a little rub. I’m a firm believer that bat surveys are governed by a set of especially capricious little bat-gods, with many gremlin-esque tendencies, always on the look-out for reasons to trip us up.

Never underestimate the importance of this aspect of pre-survey preparation

 Nobody really knows how many bat-gods there are, or what they are called, but they appear to have divided the work of a bat-worker up between them, so whatever the circumstances, never doubt that there is at least one bat-god keeping an eye on you and waiting to screw up your survey.

The first thing to know about the bat-gods is that they hate being taken for granted. “This should be a good site for bats” will always be taken by them as a challenge and at best you will spend two hours watching a lonely moth slowly fluttering around. But if you were especially enthusiastic, they may get sufficiently irate to cause a group of neds to turn up on your survey site. The best way to avoid this is to start every survey by saying, very clearly “I DON’T THINK THERE ARE LIKELY TO BE ANY BATS HERE.” The bat-gods, appeased, will then go looking for some other lonely bat-worker to bother. Unless, that is, you commit some other sin that offends them.

Another thing which which will bring the ire of the bat-gods down upon you is the appeasing of clients. If the client should show up during your survey, asking how it’s going (often a distracting event in itself), you will be tempted to tell them something positive, perhaps indicating that the survey is going well. Resist that temptation at all costs! The bat-gods, hearing you, will immediately plot some mischievous vengeance on you for failing to recognise their all-powerful position. In such a situation they will gather together in a little huddle and negotiate amongst themselves as to which bat-god will have the enjoyment of making their displeasure plain to you.

 The better-known bat-gods include:

·        The wee fat sleepy bat-god, who is in charge of making it bloody hard to get up for a dawn survey.

·        The mischievous bat-god of barked shins, who skips around the survey site, merrily scattering trip-hazards.

·        The devious bat-god who specialises in making curtains move in unoccupied buildings and making shadows resemble creepy figures.

·        The bat-god of annoying neighbours, who uses a crow-bar and a cattle-prod to extract nosey old buggers from their comfy arm-chairs and out to interfere with your survey.

·        The bat-god of batteries uses a long straw to suck power out of your detector battery, which is why your freshly-charged battery still doesn’t last to the end of the survey

·        The bat-god of padlocks plays with the minds of site owners and managers, to ensure they forget to arrange access for you.

·        The bat-god of weather has more ways of messing with you than you can imagine, but he’s especially fond of hail in July.

·        The bat-god of lost kit delights in hiding thermometers, notebooks etc. so they are left behind at the end of the survey.

·        The bat-god of urban surveys is a particularly nasty little god-let, who has at his beck and call hordes of snotty-nosed horrors specially trained to demand to know what you’re doing and why.

·        I’m happy to say I haven’t had to deal with the bat-god of car batteries for a while, but this is because I always remember to say at the end of a successful survey “I hope my car starts!”

·        As for the bat-god of car keys, the less said about him the better!

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