The addictive nature of research – Lesser Horseshoe bats in Bowland.

The object of all our effort.

It’s that time of year again when survey effort switches from the anti social dawn and dusk hours to the easier daytime, and we start to head underground to monitor swarming and hibernation sites.

Like Captain Ahab and his white whale, a somewhat smaller mammal has been keeping us searching for four years now since we first encountered a Lesser Horseshoe bat while out surveying caves in Bowland, Lancashire on Halloween (you couldn’t make it up).

The cave in question has a peak in temperature from mid October to mid November and our theory is the the bats use this to extend feeding opportunities a little bit longer as the nights get cold. And then they disappear possibly into inaccessible areas to hibernate.

From the DNA work we’ve done so far we know the Bowland bat seems to take a more basal position to current populations in North Wales and Somerset supporting our theory that we’re dealing with a remnant of the former northern range of the species rather than a recent arrival. Lessers survived in Yorkshire until 1944 in the Helmsley area so it’s not too hard to believe that an overlooked colony in a little surveyed area of ideal habitat survived unnoticed.

But the advances in our knowledge of the species here have come scattered amongst a whole load of survey effort (I don’t want to add up the hours) a bit like the return on a slot machine that makes them so addictive.

So we’re at that point again when an encounter will fill in another little gap of information, one step closer to understanding. Addictive, frustrating, time consuming and verging on an obsession but so so worth it, let’s face it if there wasn’t a challenge, if the answers came easily, it wouldn’t be half as much fun would it?…

Anabat Roost Logger

Anabat Roost Logger

 

I had a good look at the Anabat Roost Logger over the weekend of the National Bat Conference and Chris Corben was good enough to install the drivers on my laptop as well as hand over a folder of recording to get a taste of what it’s capable of recording.

On first look I’m interested. Whilst it isn’t a full blown recording detector capable of species identification, the Roost Logger will enable measurement of activity and identification to genus level. Whilst the microphone is most sensitive at 42khz the results included Lesser Horseshoe calls though the bats have to be within a couple of metres to record from what I’m told. For research into swarming and roost sites this should prove very useful for finding out when bats are active and getting an idea of what you’re likely to encounter. So Roost Logger deployed first to see where to focus survey effort and more expensive kit makes perfect sense.

The whole kit is enclosed within a small pelicase which should make stashing the detector fairly easy in most sites.

I’ve got an Anabat Roost Logger on the way for review and will be getting it straight out monitoring a cave so expect a review by the end of October……

The future of bat detectors

Don’t get too excited, it’s only a mock up

The basic rule of technology is everyhting gets smaller, more capable and cheaper, though so far the application of that rule to bat detectors seems stalled at the £1000 mark for anything of serious use.

I’ve been using Ultramics for two years now to capture realtime full spectrum recordings at Myotis swarming sites. Up until now that’s required a netbook to run the software, not massively cumbersome but combine it with infrared video kit and a trek across moorland and you certainly feel the weight.

So it was good to hear from Ivano at Dodotronic that they’re working on an android compatible version of the Ultramic; the Ultradroid. A small ultrasound microphone combined with the computing power of a 7″ tablet? The potential to record, geolocate and identify bat calls in realtime all with a full colour easily visible display?

I’ve already bought a Google Nexus7 tablet, I’m ready.

 

A new Anabat on the way? – Updated

It looks like Titley Scientific are about to release a new version of the Anabat built specifically for long term monitoring in caves, tunnels and roosts.

Anabat Roost Logger

The features all seem sensible enough:

  • Long running times on internal batteries
  • Temperature logging
  • Waterproof case
  • Sealed mic

The rugged peli case style housing looks up to the job and the (let’s hope) waterproof mic will be a great step forward for Anabat. But it raises the question; will the sealed mic be available to retrofit existing detectors?

A long time bugbear of the Anabat when used underground is the, what seems to be, inevitable burn out of the mic once condensation builds. My record is 5 mics in a season monitoring Myotis swarming sites, not just an expense but also frustrating because of lost data and downtime.

As an existing user I don’t want to replace the Anabats I already own, I want a mic that allows me to use them without that headache. It’s one reason I’ve been contemplating switching to the SM2Bat+ from Wildlife Acoustics.

Let’s hope there’s some good news for existing users too.

UPDATE

With a price of £307.20 the Anabat Roost Logger could be a game changer although that depends if it’s capable of species identification or just Monitoring activity levels and temporal patterns at any roost.

Whilst the Titley webpage states it’s compatible with existing software it’s a bit vague on what information is captured. Activity and species ID for under £500? Maybe that’s a bit ‘moon on a stick’ at the moment.

If it is just an activity logger it’s still a useful bit of kit of course, especially for initial swarming site research, but you’ll need to place more expensive kit in the field to identify what bat species are using your site.

*** Update as of 4.9.2012 Reply from Titley states that the datalogger “still presents data in sequence file and ZCA formats, the same as all previous Anabat units. The major difference is the ability to deploy it for long periods and program it to record selectively as the season changes”.

 

Preparing for swarming season

One month to go before swarming season is on us again. I’m looking forward to using the UltraMic250k this year to record swarming myotis species at some of my study sites.

Here’s some light readng for anyone interested in the use of underground sites by bats for swarming.

The Ecology and Conservation of Cave Roosting Bats in the Yorkshire Dales

Autumn swarming behaviour of Natterer’s bats in the UK

Cave selection and use by swarming bat species (you’ll need Athens for that one)

Swarming of bats at underground sites in Britain—implications for conservation

The role of swarming sites for maintaining gene flow in the brown long-eared bat (Plecotus auritus)

The effect of gates on cave entry by swarming bats

Swarming of Myotis mystacinus and other bat species at high elevation in the Tatra Mountains, southern Poland

High gene diversity at swarming sites suggest hot spots for gene flow in the endangered Bechstein’s bat

Host–parasite determinants of parasite population structure: lessons from bats and mites on the importance of time Swarming and mite dispersal

Late summer and autumn swarming of bats at Sikspārņu caves in Gauja National Park

Identification and characterization of swarming sites used by bats in Nova Scotia