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Rise of the underdog: underestimated urban bat species

In 2018, Morgan Hughes authored a regular column for Inside Ecology giving insight into the organisation, implementation and results of her 5-year PhD research project (the Urban Bat Project) looking into the assemblages and movements of bats in the urban fringe. Nearly one year on, she provides an update on how things are going and what they’re finding out …

There have been a few changes for me since last summer, as I have stepped down as chair of the Birmingham and Black Country Bat Group to take up the role of County Bat Recorder instead. This has allowed me to get more involved with the data, records and species distributions and to take a step back from the day-to-day running of the group to focus more on what I love: teaching field skills to volunteers and doing science.

At the time of writing this, clutching my coffee on a drizzly morning in August, we have so far caught 360 bats as part of the Urban Bat Project (and also have data on a further 79 bats from our pilot study in 2015). Our key focus is to look at non-ubiquitous bat species. In Birmingham and the Black Country, only three of our 12 species are considered common or frequent: common pipistrelle (Pipistrellus pipistrellus), soprano pipistrelle (P. pygmaeus) and noctule (Nyctalus noctula). At the start of the project, even brown long-eared bats (Plecotus auritus) and Daubenton’s bats (Myotis daubentonii) were considered to be ‘uncommon’, and the team were convinced that these two species were, in fact, ubiquitous, but just under-recorded. And we were right. We are finding them everywhere: there isn’t a single survey site at which we don’t catch both both species in good numbers. The causes of this disparity between the actual and perceived/recorded distribution are both biological and logistical: 1) Myotis bats are hard to confidently identify on most affordable bat detectors, 2) Plecotus bats are notoriously QUIET – ergo the big ears – and as such are difficult to pick up on most affordable bat detectors, 3) there is a distinct lack of bat workers who have the skills, equipment and/or experience to identify and record these species with accuracy and confidence and 4) the de facto assumption about biodiversity in urban areas is that species diversity and abundance is low and that distribution is truncated or significantly restricted by the infrastructure in an urban area. As a result of this assumption, recording effort is minimal (people would rather go to ‘hot spots’ or visit other counties for their survey experience and recording) and records of non-ubiquitous species are either dismissed or not investigated further or verified.

Brown long-eared bat. Credit: Morgan Hughes

My argument is to the contrary: that the infrastructure of railways (both disused and active) and canals which lattice the West Midlands conurbation (and which are a direct remnant of the transportation requirements of the long-gone coal, limestone, iron and steel industries) is a mechanism by which these species not only survive but breed, commute, disperse and thrive.

But I digress. The goal is to find and record the non-ubiquitous assemblage of bats in the fringes of the conurbation. In particular, we have been looking at Myotis species: Natterer’s bat (M. nattereri), whiskered bat (M. mystacinus) and Brandt’s bat (M. brandtii), which at the time of their last assessment in 2010 were considered to be Rare, Very Rare and Presumed Extinct within the county, respectively (Slater and Carvalho, 2018). It’s early days yet, but indicative results show that not only is Brandt’s bat not extinct in the county (it has populations in at least three of our survey woodlands), but whiskered and Natterer’s bats, though not common by any means, are at least present and widely-distributed across the conurbation.

How isolated these populations are remains to be seen, and that is the next –and for me, the most exciting – step in the project. In April this year, I was very privileged to be able to travel to Ecuador to teach BSc students bat trapping, handling and identification. As part of that trip, I undertook some training myself: taking buccal swabs from bats. Buccal swabbing involves gently rolling a small, sterile cotton swab around the mouth of an animal to collect saliva as a source of DNA material. As a result of the training, I now have buccal swabbing listed as a technique on the Urban Bat Project licence, and I am looking forward to finally collecting DNA from all our target bats. Up to this point, I could only collect DNA by analysing fecal samples, and as such if a bat didn’t (not to put too fine a point on it) do a poo in my hand while being processed, I couldn’t extract DNA. Moreover, the DNA yielded was not particularly ‘clean’ and required special (expensive) fecal DNA kits to extract. There are other methods of collecting good quality DNA, but these are often invasive and involve techniques like wing punctures. Taking buccal swabs will allow me to gather the information I need from ALL the bats we catch, without causing distress or harm, and that DNA will enable me to look at things like relatedness of populations.

Brazilian free-tailed bat (Tadarida braziliensis) being swabbed for DNA. Credit: Morgan Hughes

Other things I’m looking forward to this summer include the fact that I am speaking about our project at the International Bioacoustics Congress in Brighton in September, which I’m delighted about (though slightly scared), and I’m also incredibly humbled to have been nominated for the Bat Conservation Trust’s Pete Guest Award for outstanding contribution to bat conservation. It’s been a long, exciting and hectic summer already and we have another 12 weeks of surveys to go (weather permitting!).  You can keep up to date with the project on all social media platforms by following the hashtag #UrbanBatProject!

Reference: Slater, A. and Carvalho, S. (2018) A Standard Species Rarity Index for Birmingham and the Black Country, Birmingham.

Header image: Morgan (R) teaching mist net extraction to volunteer Caitlin (L). Credit: Morgan Hughes.

About the Author: Morgan Hughes is an ecologist specialising in bats and badgers. After growing up in south Florida, she moved to the UK where she studied Physical Geography and Biological Recording. She currently lives and works in the West Midlands. You can find her blog at www.thereremouse.com and on Instagram and Twitter where you’ll see updates of her survey work.

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