Dr Tina Aughney of Bat Conservation Ireland www.batconservationireland.org gave the Network an excellent presentation on the bat species to be found in Ireland on Weds 4th June 2014. You can download a pdf of her presentation here.
The talk was followed by a practical workshop in bat detection along the Ulster Canal Greenway at dusk, where we found a roost of soprano pipistrels and also spotted several Leislers bats – there is a large colony of ‘regional importance’ in Monaghan town. Ireland is the most important location for Leislers bats in the world, so it was wonderful to learn that Monaghan is playing its part in conserving this important species.
Bats are Ireland’s only airborne insect eaters, and thus play a very important role in controlling the numbers of insects. Different species of bat are adapted to hunt over different types of ground. For example, Leisler’s bats have long wings which make them fast over open ground but less manoeverable, so they prefer to hunt over open ground, where they look for ‘clouds’ of insects, then swoop to feed. Other species such as Natterer’s bat prefer woodlands, where they flit in and out amongst the trees. This calls for shorter wings which can turn quickly. The pipistrels are the most adaptable species of bat, and tend to hunt along hedgerows, where they can combine the tree cover with venturing out into the edge of fields. Daubenton’s bat feeds by skimming low over water, and can swim!
It’s not just the wing span which differs from species to species; while all Irish bats use echolocation (bouncing sound off objects to determine their location) to navigate, each species has its own unique ‘call’, which is related to the habitat over which it hunts. The woodland bats emit short, quick calls and because the sound doesn’t have to travel far, their calls are very soft. Bats flying over open country like Leisler’s bat, emit a longer, louder sound, as it has to travel further before it ‘bounces’ into anything. Bats emit their echo ‘calls’ with each beat of their wings, so it is no surprise that their flight patterns vary from species to species. Pipistrelles tend to ‘flit’ erratically, whereas Daubentons and Leislers tend to go in for straighter flight paths.
So if you’re observing bats with just your eyes, you can still make a good guess as to their species: if it’s flying quite high up, over open country, and beating its wings quite slowly, it’s a Leisler. If it’s hunting along the edge of a field, flitting over and back erratically and quite low, it’s probably a pipistrelle. And if it’s skimming low over the surface of a lake or river, it’s a Daubenton.
You can use a ‘bat detector’ to help to identify the species more accurately. Each species has a unique pattern and pitch to their ‘call’. The bat detector picks up these sounds and ‘translates’ them down to a sound which is within the hearing range of us humans. The detector has a dial, which you use to move up and down through the frequencies until you pick up a ‘call’. The pattern of the call, and the frequency it is being heard at, tell you which species of bat you’re listening to. This is the only way to distinguish some species from one another; for example, there are three species of pipistrelle in Ireland, all of which are similar in size, fly and feed in a similar way and use similar patterns of sound to echolocate. However, they emit their ‘calls’ at different frequencies, so it is easy to tell which species you’ve got if you check what frequency you’re picking up the calls at.
Bats are a fascinating animal, and form a crucial part of Ireland’s biodiversity. Bat detectors are available for loan from Monaghan libraries – just ask for the Biodiversity Kit, which includes all kinds of aids for identifying plants and wildlife – so get out there and explore the hidden world above our heads!
Bat Conservation Ireland are asking for volunteers to help them to conduct an important survey of Daubenton’s Bat in August. The survey involves walking a 1km stretch of river two nights in August – once at the start of the month, and once at the end – and stopping every 100m to observe the water for 4 minutes and count the number of bats which pass low over the water’s surface. You will be given a bat detector to use, and a training evening will be held for volunteers on Tuesday July 8th. A certificate acknowledging your assistance will be provided by Bat Conservation Ireland – you can use this as part of your Tidy Towns entry form next year.
If you’re interested in participating, please complete the form below, which will be forwarded automatically to Bat Conservation Ireland.