Wednesday, 8 September 2010

A rant about problem bats

Yes, it's true, there is such a thing as a problem bat roost. Regrettably once in a while a bat colony makes someone's life difficult through noise, smell, stray bats in living areas, phobias etc. A big part of the skills of competent bat-worker relate to communicating with people and trying to find solutions which allow bats and people to share a building in harmony.

Here in Scotland we have an excellent system of contract bat-workers (I am one), employed on a casual basis by Scottish Natural Heritage, who visit people with bat problems and work with them to try to identify solutions. We also have a streamlined licensing process for domestic properties, to allow problem bats to be appropriately and safely excluded after the breeding season is over (most problem roosts are maternity sites). As a result we should be able to avoid the negative publicity for bats which could result from unhappy people suffering bat problems without help or support...or can we?

In my opinion there are three problems with the system as it stands.

1. Only domestic premises are included. Shouldn't big business pay their way? Of course they should when they cause problems, but we're not necessarily talking about big business.

What about the small business, struggling to make any headroom in a difficult economic climate, such as the hotelier near Dumfries I recently met? He was at his wits end trying to keep his business afloat whilst a Soprano Pipistrelle colony made two of his bedrooms stink. Is it reasonable for him to have to pay several thousands pounds he doesn't have for a consultant to carry out surveys and deliver a mitigation solution under license?

What about the Primary School who recently hired me to help with the Soprano Pipistrelle colony which were turning up in classrooms all over the school, creating havoc? Shouldn't their budget be spent on books and teachers, rather than consultancy fees (heavily discounted, I have to say) and a heated bat box as licensed mitigation?

With SNH refusing to help in situations like these, the risk is that people will choose to find their own solutions, with disastrous results for bat conservation. The hotelier had already done exactly that.

2. Domestic licenses for exclusion are streamlined and supported by SNH... up to the point when the license is issued. At that point the householder is left with a license and a leaflet advising how to carry out an exclusion (admittedly an excellent leaflet). If there are any complications the license may state that a licensed bat-worker must be involved, but the support has stopped, so the householder is left to sort that out by themselves. Surely the point in the process when SNH supervision is at its most critical is the physical exclusion? This is the moment when it could all go horribly wrong due to misunderstanding or indifference on the part of the householder. And is it reasonable to expect the householder to track down a consultant and pay consultancy fees? Some bat groups do great work filling the gap here, but not all have the numbers to be able to do so.

3. Domestic licenses do not usually require mitigation to be put in place. This is perhaps not unreasonable. Expecting householders to spend many hundreds of pounds on a heated bat box is a sure way to ensure their neighbours quietly kill their bats, instead of seeking help and advice. However, I have now encountered several situations where a problem bat colony has been excluded, no mitigation has been put in place and the following year there is a call from another house nearby: we have simply moved the problem on.

Of course mitigation measures are rarely used immediately by bats, but if centrally funded mitigation measures were put in place the number of repeat problems would inevitably diminish.

This is a thorny subject, especially when there is a massive squeeze on government funding. But if bat conservation is to be best served a number of facts seem clear to me:

1. Incidences of problem bat roosts should be dealt with quickly and sympathetically, regardless of who they are causing a problem to. Beaver reintroductions in Germany succeeded precisely because of this sort of open and supportive approach.

2. If a funding stream were available (and that's a big "if") then mitigation measures at domestic exclusions could become a norm instead of a rarity, with direct positive results for bat conservation.

3. SNH support for problem bat roosts should be a start to finish process. What is the point in providing a fantastic service to bats and householders for half the process and then walking away, allowing all the good work to be wasted as the householder gets fed up and tells all their friends that she wishes she had simply blocked up the roost entrance and told no-one about it.

Of course it's easy for me to sit here and carp: I don't have the thankless task of balancing SNH's budget. But on my desk lies a copy of SNH's glossy quarterly magazine and I notice the teas and coffees at this weekend's National bat Conference are sponsored by Natural England. I'm grateful for both... but I can think of better ways of spending the money.

IMPORTANT NOTE: In the UK and Europe all bats are protected from disturbance and attempting to exclude bats or otherwise disturbing them is a criminal offence.

If you have a bat colony in your home or premises and need help or advice (in the UK) contact the local office of the relevant statutory nature conservation organisation: Scottish Natural Heritage, Natural England, Countryside Council for Wales or Northern Ireland Environment and Heritage Service.

Help and advice can also be obtained free of charge from the Bat Conservation Trust bat helpline on 0845 1300 228.

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Monday, 6 September 2010

There are bat detectors...and there's the SSF Bat2

For some time I have been wondering what the next steps in bat detector technology would be. For a while it looked as though it would be the long-awaited Bat Box Griffin: heterodyne, frequency division and time expansion in one unit, with in-built recording. That may well prove to be a world-beating piece of equipment, but it's launch has seen many delays (though in the 21st century it's nice to see a manufacturer which respects its customers enough to perfect a product before launching it...Microsoft Vista comes to mind).

Last year the Italian Dodoultra promised digital processing and many clever features. Possibly they were delivered but it really didn't matter as the detector was woefully poorly designed in terms of ergonomics and usability in the field. The Dodoultra's manufacturer ignored two simple facts of bat detector design: bats move around fast and they do it in the dark. Detectors need to be easy to use and swift to change function. The Dodo delivered neither and followed it's namesake.

So when I heard of a new detector from SSF in Germany with clever functionality I was cynical, to say the least. However I am a sucker for new toys and so 160 Euros was spent on a shiny new SSF Bat2. Note that price: 160 Euros, delivered from Germany is good value for a decent quality heterodyne detector. But the SSF2 isn't just a decent quality heterodyne detector, it turned out to be rather more than that.

If I were to ask what are the major drawbacks of using a heterodyne detector, compared to say and £1800 Anabat+PDA you might say these:
1. The hassle of tuning up and down in order to find bat calls.
2. The difficulty of identifying the peak frequency of a brief bat pass.
3. The risk of missing a bat because you're on the wrong frequency.

The Bat2 display shows the frequency the detector is tuned to, as you might expect. But it has three other displays. Firstly, there is a second frequency display, which shows the peak frequency of the bat call you are listening to. Hit one of the four buttons on the front of the detector and the detector jumps to that frequency (and unlike the Dodoultra, which also included this function, it works properly. The Dodo had a tendency to latch onto harmonics, instead of the main call). Pipistrelles and other frequency-critical calls can be swiftly tuned to peak, even during a brief pass.

All heterodyne detectors have the problem that they only receive a limited range of call frequencies at one time. How broad a range depends on the individual detector, but between 5 and 20 kHz is usual. Of course this means that, if you are tuned to 20kHz, listening to a Noctule and Greater Horseshoe flies past you are going to miss it. The Bat2 includes a small graph on it's display, showing the frequency range of the received call. In theory this means that you can see that Greater Horseshoe, though you would have to be walking about staring at the display, which means you're not going to see any bat behaviour and will probably trip over a tree root. Nonetheless it's a handy function.

The Bat2's tuning is controlled by up and down buttons on the front. If. like me, you like the thumbwheel tuning on the current generation of Bat Box detectors you may view this with the same suspicion that I did. It turned out to be surprisingly usable, even one-handed (as every chiropterologist knows, bat surveys require at least three hands). Cleverly, the detector has four user pre-set frequencies which can be jumped to by pressing a button, thus removing the tedious need to c=tune from one end of spectrum to the other.

All good stuff so far, so what's are the downsides? Well, apart from it only being a heterodyne detector (and surely that graph indicates that this machine must be processing frequency division internally? Couldn't it have an FD recording output?) the only complaints I have are very minor. The battery compartment is held shut with a small Phillips screw. Nice and secure, but hardly the game you want to be playing in the dark at 2am when the batteries run out.

My other niggle also relates to the batteries. It uses 4 AA batteries, which makes it a little heavier than other detectors which use 9volt PP3 batteries, but not enough to be a problem. I found that the battery indicator read low as soon as I inserted a fresh set of batteries. It took me a while to realise that rechargeable batteries only deliver 1.2volts, compared to the 1.5volts of a dry cell. Thus, the Bat2, when presented with rechargeable batteries registers low battery, regardless of the state of charge.

All in all I am delighted with my Bat2 and for the time being it is my detector of choice for watching bats, though for anything where I may need to review calls later I'll still use an Anabat+PDA or a Bat Box Duet and digital recorder. Please SSF...bring out a frequency division version...oh, and a handbook in English would be nice.

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Sunday, 5 September 2010

WW2 Bunker to Bat Hibernaculum

Several winters ago a couple of good friends and I were searching structures I had trawled from an archeaeological database, in the hope of finding previously unrecorded bat hibernaculum. A group of massive World War 2 structures had caught my eye on a satellite photograph. These turned out to be former RAF bomb stores - useless for hibernating bats, but now handy cattle sheds for a farmer.

Nearby a small square of concrete on a small hillock within a pasture field caught our eye. Taking a closer look, we found a small hole in the ground alongside the concrete square. When we crawled through the hole we found a hidden world. A group of brick-walled underground rooms formed an airfield defence bunker. The concrete square was a pill-box, allowing the commander a 360 degree view of the surrounding RAF airfield, now long gone.

The bunker was humid and seemed to have the sort of steady low temperature suitable for hibernating Myotis and Brown Long-eared Bats. Whilst it was full of historical interest, including an iron bedstead and a utility WC, sadly there were no crevices in the masonry which could be used by hibernating bats. Nonetheless, I couldn't help thinking it had potential and that fact was filed away in the tardis-like bucket of trivia which masquerades as my brain.

Fast forward two years to a conversation with Stuart McPherson of East Lothian Council and my randomly-wandering brain spat forth the news of this potential bat hibernaculum on his patch. We arranged to look at the site with the landowner and a plan was hatched. With a generous grant from Scottish Natural Heritage we would dig out the entrance to the bunker, to give bats easier access and to help them to find it. Inside we would install crevice boxes to facilitate hibernation and a hedge would be planted, linking the bunker to nearby woodland and hedgerows.

The difficult part was going to be the clearance of several tonnes of soil and rubble. "No problem" I blithely said, promising that Lothians Bat group would be able to produce a team of volunteers to take the work on (and provide funding in kind to balance the SNH grant). With my fingers firmly crossed I wondered how long it would take to do it on my own....

I needn't have worried. One August weekend found a team of 7 intrepid bat workers, equipped with spades, shovels, picks and buckets, together with a tractor and trailer provided by the landowner. I am here to tell you it is simply astonishing what a group of bat-centric conservationists can achieve when two and a half tonnes of spoil needs digging out and moving. As well as making the bunker far more accessible for both bat workers and bats we discovered all sorts of reminders of our 1940's forebears. The star find, considering this was an RAF base was an empty brylcreem bottle!

As ever, Nigel Terry went above and beyond the call of duty, splitting his trousers as he toiled and sweated. This blog can exclusively reveal the highly appropriate nature of what was revealed....

Words fail me!

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