Mammal Week 2019 - Barbastelle bats

Flying bat, hidden roost

by Kieran O'Malley

It is early May 2019 and my life is squashed down to just a few bags that I can (somewhat) comfortably carry on a bus from Leeds to Brighton. This is no weekend getaway, but the start of my 4 year-long PhD at the University of Sussex on one of Britain’s rarest mammals, the barbastelle bat.

Bats have captured my interest for several years, ever since I ventured into the world of caving during my first year of university (it seems I am destined to spend my waking hours in the dark). It was my master’s, however, in which I spent my time with African Bat Conservation in Malawi that really got me interested in researching bats. Here, I saw a huge variety of bat species. Fruit bats, tomb bats, horseshoe bats, leaf-nosed bats… It seemed that there was a bat named after everything! Yet, I couldn’t help but notice that despite the astonishing diversity of bats they do not seem to be fairly represented within many academic curricula or indeed within many countries’ environmental policies.

Back in the UK, centuries of exploitation and deforestation have led to unprecedented habitat loss for mammals, including bats. Only 2% of the UK land area remains covered by ancient woodland, which now acts one of the last remaining oases for many species such as the barbastelle bat. Ancient woodland is crucial for barbastelle persistence as it provides ideal roosting habitat in the form of cavity-rich standing deadwood. However, whilst seemingly a popular species amongst bat enthusiasts, with their distinctive pug-like appearance, there seems to be a disproportionate lack of research focusing on them. This is where I aim to come in.

On the surface, the premise of my PhD is rather simple. By better understanding the reasons for the current distribution of barbastelle roosts I can hopefully determine what actions should be taken to improve the landscape for them. Unfortunately, this is somewhat impeded due to a lack of information concerning the current population size of barbastelle bats, the location of their roosts, or how best to effectively survey for them.

In an attempt to address some of these problems I have spent the past summer testing various survey methods and deploying static detectors (microphones that pick up passing bat calls) within ancient woodlands. This work resulted in lots of sound files (around 170,000 in fact), all of which I needed to check for the presence of barbastelles. But by comparing the times of barbastelle passes with the time of sunset I am able to start to build a picture of whether a woodland contains a roost or not.

This is all just the first step. Once I can establish which woodlands have roosts, I can start to work out why a particular woodland is favoured and how woodlands can be improved for bats. However, for now it is back to the office for the winter. I will continue analysing the data I collected over summer for the next few weeks and then it will be onto planning the next field season!

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