Hmm, interesting, we had damp appear on our gable end bedroom and investigation resulted in an entire wall filled to the brim with bat poo. My daughter and myself stood at another bedroom window and counted 21 bats coming out at the eaves, they are back we just left them. I understand they go away for the winter and return late spring. I think they are in all the buildings here, they are protected so just leaving them, they will have lived here longer than we have no doubt.