bats can also be viewed with a thermal viewer – usually they are much warmer than the background (at least in northern Germany). Here are some videos…
Pipistrelles are swarming at the Kiel Kanal bridge in Levensau – looking towards the top of the bridge
Pipistrelles are swarming inside the Kiel Kanal bridge in Levensau – during the „bat night“ access to the (otherwise closed) inside was possible
Nyctalus noctulae leaving their box, very hot pixels are marked red
Pipistrelles hunting over a lake
Pipistrelles (pip. pygmaeus) hunting over a small pond in a forest
The limiting factor in these videos is not the low resolution of the thermal viewer (the detection range actually exceeds some other night vision devices and ultrasonic detectors), but the low frame rate of 9 Hz. Devices with higher framerates cannot be exported from the USA.