Fun Fact: The Royal Botanic Gardens in Sydney Australia is home to a large number of Flying Foxes.
Today we had a look at some more bat detectors and the software that can then be used to create and analyse sonograms.
- The Frequency Division Detector: which acts by dividing the incoming frequency by a factor of 10 resulting in a sound that can be heard by the human ear. Sound is captured continuously and in real-time.
- Time Expansion Detectors: capture a brief second of a call and then slows that down by a factor of 10, allowing the entire structure of the call to be analysed.
- Full Spectrum Real Time Sampling Detectors: combines the detailed call analysis and real-time sampling.
Check out the website below for additional information.
It is amazing what you can learn from a sonogram,e.g. the shape of the call of the Common Pipistrelle is a hockey stick shape as is the Leisler’s (albeit it a slightly longer shape). These calls are in contrast to those of the Myotis species where the calls appear as a straight line.
In Ireland, bats mainly live in man-made structures and deciduous woodlands(ideally near water). Loss of habitat is a huge and ongoing issue and loss of roosts may be as a result of timber treatment, tree felling, disturbance by other animals such as cats and water pollution to name but a few.
Research is currently underway to study the effect of windfarms on bats in Ireland.
With regards to the wind turbines, it is thought that bats can be injured or may die in two ways: Firstly, by direct collision with the blades of the turbine. Secondly, there is a pocket of low pressure just behind the blade. If the bat gets caught in this pocket it is thought that the change in pressure will result in haemorraging of the lungs, similiar to what divers can experience with decompression sickness (the bends). The current research is looking at seasonal patterns in bat presence, bat activity during high risk periods, evidence of bat movements and bat activity during winter (it is thought that Irish bats don’t migrate). The research is focusing on striving to find answers to the following: when are the bats on/not on the wind farms and why. A large amount of transects have been studied to date and the data will be used for Species Distribution Modelling and to identify areas that are unfavourable for bats and suitable for windfarms.
We also looked at different types of nets/traps that are used to capture bats with minimal distress. Firstly, we looked at a Mist Net which is a mesh of nylon that is suspended between 2 poles. The net is quite delicate and care needs to be taken when unfolding or folding it away as a mass of tangles may ensue (think Christmas Tree lights)
The second type of net that we looked at was the Harp Trap consisting of layers of ‘harp strings’ suspended from poles.
A fanatastic 2 days. Thanks Una.