Wind turbines and bats : a new way of study

Bourges natural history museum is recording bat echolocation calls at high altitude.
The aim of this study is to catch signals at levels where wind turbines are active, around 80 meters.
After a few months of balloons testing, we actually are working with a small airship equipped with an ultrasound system recorder. Different landscapes have been tested, mostly in Center France : open fields, forests, hedges and meadows area.
Actually, with more than twenty nights of practice, the balloon system is efficient and bringing a lot of new datas. For example, information recorded at ground level are mostly different from those at high altitude level. No signals have been recorded coming from Rhinolophidae and most of the other contacts are from Nyctalus and Pipistrellus.
The invention seems to have a great interest in the bat worker community, and right now Germany and Belgium are ordering the small airship to do their own work.
During winter, new recording equipment will be tested in Bourges.