We have 18 different species of bat found in the UK. And only 9 of which live in Scotland. And up North where we are at Forsinard, even fewer! This is because the climate is colder up here with wetter cooler weather, we have shorter nights in the summer and there are fewer trees. This only allows the hardiest of bats to survive! Because I have a personal interest in bats I have tried to use my time at Forsinard to have a look at the bats we find here. Bats need trees or buildings to roost in, so it would be very unusual to find them out on the open bog. But as there are native trees in the Straths and some of my colleagues have roosts in their houses I was able to see plenty!
A Pipistrelle at the visitor centre!
A few of us conducted a waterway survey looking for Daubentons bats Myotis daubentonii which is a species of bat that hunts over rivers and waterways. We do not have records of them on the reserve but they are found into Sutherland so we thought we would survey the Halladale River just to see. We spent two evenings walking along the river to survey for Daubentons. Our survey didn’t see any Daubentons, but we did see plenty of Common Pipistrelles, Pipistrellus pipistrellus. You may wonder how you can tell the difference between bat species, in the dark!? Firstly you can look at how they fly. Daubentons fly low across the water, skimming the surface for insects. Pipistrelles do not do this. Secondly is the size, Daubentons are larger than Pipistrelles, but this is obviously difficult to see if the two species aren’t flying next to each other! So finally the best way to tell them apart is by listening. Bats use something called echolocation to hunt. Echolocation is a biological form of sonar; the bat makes a call and listens for echos formed as the call bounces off objects. By listening to the time it takes for the echo to return the bat can tell how far away it is, and also from which direction. This allows the bat to make itself a sound map, which it can use to hunt and to navigate. Each species of bat uses a different frequency of call. This is because each species is hunting slightly different prey, or living in different habitats, so they use different sounds. Most of these are sounds that humans cannot hear, so we use a bat detector! This is a little hand held machine that you can set at the frequency to listen to the bats. Because the common Pipistrelle calls at 45kHz and the Daubentons at 35kHz with different sounding calls, we can identify them by this!
Enjoying the displays and baking at the Halladale Hall!
On Sunday the 31st of August we held a bat evening at the Halladale Hall as a celebration of International Bat Night. With wonderful batty home baking from our very talented baker Yvonne, plenty of tea and coffee and the hall to keep us dry we waited out the rain. We also had lots of information from the Bat Conservation Trust (BCT) to read and look at. BCT were also kind enough to lend us some bat detectors to use. So after the rain and a bit of a wait we finally saw our first bat: the hardy common Pipistrelle. Bat detectors switched on we watched, and heard, the bats emerge from their roost, to spend the night hunting midgies (thanks bats!).
Batty baking, beautiful and delicious!
Hearing a bat for the first time is exciting. You can see them flying around you but not until you turn the bat detector on can you hear the wonderful calls and sounds. It’s like being let in on a secret!
http://www.bats.org.uk/