Greater mouse-eared bat (Myotis myotis) striking a pose like Batman's "Batmerang".
Actually she did come back and flew right into the same net in which she was caught the first time. But she was set free again and luckily did not return a third time. ^^

I guess she stays in one of the old WWII bunkers with her conspecifics during the day, but since greater mouse-eared bats are pretty common around here and are not limited to forests and my task is it to find the roost of mainly forest inhabiting species, she did not get a sender and I don't need to track her. Honestly, it would be nearly impossible to radio track a bat which is hiding under tons of concrete and soil, so I'm quite happy about that!