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Friday, 16 May 2014

Nathusius the next chapter

What could be even more exciting than 2 Nathusius pipistrelles?

Last night we caught our sirt bat in our new herp trap.
We set up four harp traps and acoustic lure as part of the Nathusius Pipistrelle Project. There was an ecstatic reaction  when this beast fell into our harp trapLeisler wriggling

She was not best pleased to be caught and wriggled a ot – as this photo shows.

But we forgave her everything but she was a Leisler’s bat. This is the first time we have ever caught a Leisler’s in the county. We have thought that we have heard Leisler’s in the past, but they are very difficult to distinguish them from Noctule if you listen to the sonograms
Once she had settled down, Bob managed to get some better photos of herLeisler side view crop1

Leisler's bat. Photo Bob Cornes
Leisler’s bat. Photo Bob Cornes
We are over the moon – even if I have to writer a new page for the bats in Bedfordshire Section of the website
Leislers crop2

Nathusius Surveys

Last night we were joined by Daniel Hargreaves in order to harp trap near Biggleswade. Four harp traps and acoustic lures were set up and three of them caught bats.

Daniel returned from checking one trap bearing 3 bats with him.
Nathusius, Common and soprano pipistrelles. Photo Bob Cornes
Nathusius, Common and soprano pipistrelles. Photo Bob Cornes

You can see that the Nathusius is bigger and furrier than the other pipistrelle series.
This was the cause of much delight as it is only the second Nathusius ever caught in Bedfordshire.
Later that night a second Nathusius, also a male, was caught – much celebration followed. Both bats were ringed and a fur sample taken for DNA analysis
Since the  Bat Conservation Trust Nathusius Project began in April, Nathusius bats are being found all over the country. We have spend the last month looking hard, so it was great to catch one. Now we will be going back once a month to resample the site  (under the terms of the Nathusius project)
Nathusius pipistrelle. Photo Bob Cornes
Nathusius pipistrelle. Photo Bob Cornes
Nathusius pipistrelle3
Nathusius pipistrelle Photo Bob Cornes

Sunday, 16 February 2014

Last Hibernation Survey

This weekend saw the last hibernation surveys of the year. 

On Saturday 114 bats were found in total. Sundays results are not currently in, but an updated when they are. 


Friday, 31 January 2014

Hibernation update

Last weekend's hibernation survey has again broken records, with a total of 172 bats (previous highest 168 in Dec 2012). The December 2013 was 
106, possibly because the mild weather had not driven bats underground 
as early as the last couple of years. 

The January breakdown was:

119 Natterer's (previous highest 91). This is a dramatic increase.
38 Daubenton's (not exceptional - there were 44 in Dec 2012)
11 BLEB (down; the record was 22 in Jan 2011)
2 Barbastelles (there were 3 in December, but this is well down on 
recent winters. The record is 25 in Jan 2011)
1 Pip. sp. (the first recorded since Jan 2012)
1 unidentified

The significant changes were the increase in Natterer's and decrease in 
BLEB and Barbs. The only one of these which fits a consistent pattern 
over several winters is the drop in Barbs after mild winter weather so 
far. There is no obvious explanation of the changes in Natterer's and BLEB.


Wednesday, 15 January 2014

First Hibernation Checks

The first of three hibernation checks have been made and the following bats were found: -

106 bats in total:

61 Natterer's
26 Daubenton's
2 Myotis sp.
14 BLE
3 Barb


Friday, 22 November 2013

Bats and Breathable Roof Membrane what’s all the Fuss?

As bat Ecologists we are often told/asked by Architects that they will/would like to use a Breathable Roof Membranes (BRM) in there development project, however we advise that they are not used when bats are encountered. Why?

Background: -

BRM’s are increasing used in modern buildings due to their energy efficient nature, current insulation standards and their ability to allow water vapour (but not liquid to enter) to exit the roof void. Formerly traditional materials such as felt and air-bricks were used to prevent water vapour build up.

BRM’s are produced using layers of non-woven materials that are then bonded through pressure and heat. A long polypropylene fibre is used to produce the outer layer and it is this that has caused concern amongst bat workers.

Although common, most people don’t realize that some bats (due to habitat loss) now rely on man-made structures for shelter and security, often this is a dwelling or similar. This is where problems arise and these often go unnoticed due to the bats habits.

What are the issues?

There are three main issues with BRM’s and bats: -

1.    Entanglement or trapping

2.    Microclimate

3.    Membrane longevity


For Ecologists this is by far the most concerning aspect of BRM’s and bat interactions. Although not scientifically proven (to date) anecdotal evidence strongly suggests that bats are getting trapped in the fibres of the BRM. Stacey Waring is currently undertaking a research project on this very subject and the evidence gained strongly suggests bats do get entangled, check out her Blog


A traditional felt lined roof will have very different thermal properties to a BRM (Waring, S. et al 2013). However the research here is lacking and other than the obvious there is no way of knowing the effect that BRM’s may have on a long term roost.

Further research in roosts that have been changed from a traditional felt to BRM needs to be undertaken. It is however likely that temperature and humidity will be affected (Waring, S. 2013)

Membrane Longevity

Again research is lacking but anecdotal evidence suggests that damage to the membrane can occur from when the bats claws become entangled. This causes something called ‘fluffing’. This is where the fibres of the BRM fluff up to form a cotton wool like structure on the surface of the BRM.

Other concerns are the oil in bats fur, urine and droppings causing the BRM to lose its water vapour/proofing properties.

This in turn could cause damage to the BRM installed and the water vapour and water tight properties of the BRM to become reduced or useless (Waring, S. et al,2013).

So, which BRM’s are suitable to use when bats are present?

Well the simple answer is, none!

Current advice is not to use a BRM in a roof where bats are going to be encountered. Traditional bitumen felt (although having its own issues) has been used for over 100yrs, with only a minor number of reports of bats being entangled.

Put simply, if bats are going to be present in a roof following re-roofing or a new build following demolition of an older building a traditional felt should be used. Although there is an increase in the use of the BRM current Building Regs allow the use of a traditional felt, normally known as a ventilated roof system.

References: -
Waring, S. 2013,, assessed on 25/11/2013
Waring, S. et al, 2013, Double Jeopardy: The Potential for Problems when Bats Interact with Breathable Roof Membranes in the UK.

Monday, 7 October 2013

The Last Bat Group Survey of the Season

As the bat survey season winds down and planning surveys can no longer be undertaken, it gives us consultants a chance to put some time back by volunteering for bats.

At this time of year bats are preoccupied with mating and checking out hibernation sites ready for winter.

Last night I organised an autumn swarming survey (this is different to dawn swarming, in that it occurs over hours rather than 15/20minutes and goes late into the night).

A site we have had access to for several years now just outside of Luton already has one autumn swarming site confirmed, however we wanted to check another area that was a former Bothy (semi-underground, gardeners den (for want of a better description).

So last night (06/10/2013) 8 of the bat group keen to get in one last survey headed off to try some harp trapping and mist netting.

We walked down to the site and proceeded to set up just after dusk. Following the set-up we all settled down to wait.

Nets and the trap were checked regularly, but other than the odd Pipistrelle (common and soprano)call nothing was heard.

Some time later at approx. 21.00 the harp trap was checked, not expecting anything to be in the trap, a quick glance suddenly showed a bat. This turned out to be a male Daubentons bat, most probably a juvenile.

This was the first of several more bats caught, with a total of  six Natterer's again all male and last but not least a male Barbestelle

                                          Photo: - Barbestelle in the hand (Martin O'Connor)

This Barbestelle is a new species for the site and is the first to be caught this far south in the county, it could well be a cross border bat, given that Hertfordshire is only a stones throw from the site, but nevertheless it was caught in Bedfordshire.

All the bats caught were male and the site is now confirmed as the second autumn swarming site within the grounds of the estate.

This was my first opportunity to handle a Barbestelle, having only seen them 'up close' in hibernation or missed them on previous netting sessions due to having to leave early for work the following morning.

So in total nine bats were caught, six Natterers, one Daubenton, one brown long eared and one Barbestelle.

This goes down as the best night at this site and confirms the estate as probably the best bat site in the south of the county and by far in Luton.

                                          Photo: - Daubentons being weighed (Martin O'Connor)

Photo Bob Cornes
Photo:- Natterers bat with hair loss (Bob Cornes)

Monday, 16 September 2013

Sad News


I write this with a heavy heart, having set-up this Blog to inform you all of the progress of the Noctule that was brought into captivity some 3 and a bit years ago. Then she give birth and the saga of the release of the pup followed.

Over the last three and a bit years this bat has worked for the bat group as an educational bat and has reached many 1000's of people. Helping to dispel myths and fears of these wonderful creatures.

She has been to schools, WI meetings, events and many other functions. She was much loved by the group and it is sad news for the bat group and those that have meet her over the years.

Unfortunately over the weekend (13/09/2013) she died whilst being looked after by one of the bat care team (I was away for the weekend).

She had been displaying some symptoms of being ill, such as being bunged up and going off her food. And although we did everything to help her the efforts were in vane.

This blog will continue in her memory and hopefully bring better news in the future.

Wednesday, 4 September 2013

Wildlife Acoustics EM3

This March I was told by my MD (I am a bat consultant) that he was upgrading all of our equipment, so after much looking around, I came across the Wildlife Acoustic EM3 handheld detector. I had been aware of it, but hadn't given it much thought due to the price.

I had been using a Petterrson D240X with recorder for much of my work and although it is an excellent detector it can be cumbersome due to all the wires running to and from the detector.

The EM3 seem to fit the bill for what we wanted e.g. handheld, built in recorder (with several formats, I use WAV) and it had a screen which allows the sonogram to be displayed.

I have now had an EM3 for the whole of a bat season and have come to grips with using it. Hence this little review.

On first thoughts I didn't really like it to much!

It was quite large in the hand (although I have fairly large hands), it was complicated and not intuitive and it ate batteries (even though these are re-chargeable). The real time expansion (RTE) sounded odd compared to the D240X and the heterodyne mode although good was difficult to scan though the frequencies.

The build quality looked poor and it lacked a lanyard to secure it, when fumbling around in the dark, so it could be dropped.

However: -

I have come to love using this detector and really would be lost without it!

The sonogram screen although small is just excellent, allowing almost instant confirmation of the species your listening to (assuming it is not Myotis or other difficult species) and you can zoom into the call if you if you need to. You can toggle between a white background and dark background to save your night vision. Recorded without the need for other devices and loads of wires everywhere and instantly check the call on the screen .

Having now learnt how to set it up to my needs (check the Wildlife Acoustics website for tutorials) the detector has taken on a life of its own. I now listen in RTE as standard so that I don't miss any bat passes and don't have to fumble around with buttons on the wrong side of the detector. I have changed the trigger level of the detector so unwanted noise is not recorded and it saves the files in small snippets making sound analysis fast.

There are still problems with this detector, for instance changing the buttons to the left side would be a great help as I am right-handed, adding a lanyard to the case to prevent dropping it in the dark and installing a more sensitive microphone would all be good additions.

However with all that said, I really couldn't do without this bit of kit anymore!


Swineshead Re-Visited

Swineshead revisited

Last week the guys headed back to Swineshead wood with the aim of catching and perhaps tagging one of the Myotis bats we heard earlier in the year.

We were joined by Daniel Hargreaves who stopped off on his way to Luton Airport for a flight at silly o’clock this morning.We set up two harp traps and lures and settled down to wait. We didn’t have to wait long before not one but three bats entered the first harp trap.

We caught a male Natterer’s and the first of four barbastelles in beautiful condition
But the third bag was the most exciting and indeed the most satisfactory in purely dramatic terms, for therein rested a male Nathusius. This is the first Nathusius we have had in the hand for twenty years. The only previous sighting was a single male who was found grounded and died soon after.
Nathusius pipistrelle Photo Jude Hirstwood
Nathusius pipistrelle Photo Jude Hirstwood
This bat had very large buccal glands as you can see in this photo and was in full breeding condition .
Nathusius pipistrelle. Photo Bob Cornes
Nathusius pipistrelle. Photo Bob Cornes
Nathusius pipistrelle with prominent buccal gland. Photo Bob Cornes
Nathusius pipistrelle with prominent buccal gland. Photo Bob Cornes

Swineshead is quite a way from the nearest large water bodies.Perhaps he was migrating in a quest for females.

One thing is sure, this really is an exceptional wood!.

Nathusius males sit in a suitable spot and call, often all night in the hope of attracting a female. You can see Daniel Hargreaves’ video of an advertising Nathusius  on You Tue