Another possibility is infra red photography, Erik Korsten is the master of this—take a look at his extraordinary video of Natterers bats emerging from a tree roost .

 

This is also the way in which the bats in the Forge at Confort Meilars are monitored, by an IR camera in the attic, as this causes no disturbance to the bats but it provides a splendid window on their world.

One issue which photographers might bear in mind is the effect of their camera’s ultrasonic motors on the bats. Bats will be able to hear the noises that we cannot as the lens uses its motors to focus. It is best to focus manually and not to linger too long – take a quick shot and go – for the welfare of the bat. If we do not know the effect of these sounds then it is better to err on the side of caution.

LH photo taken on 6400 ISO

 

RH photo taken on 3200 ISO