Additional question - Can you give further details on the observation e.g. behavior, habitat etc:
When I see them, they are flying. I guess they are hunting for food. We have a forrest behind our house. There are quite a lot of old trees. Our house is in a corner of a little field. We moved in to our house by the end of october 1984 and I’ve seen these bats during summer evenings ever since then. While they fly they make a sound like a peep.