Bats in the Belfry

Ok maybe its not a Belfry but a regular ol attic, details. My house has been more or less vacant for two years and it was built in 1910. These two factors seem to have produced a bit of a bat problem, one I normally would have been blissfully unaware of. But my precious kitty is taking care of the problem for me one bat at a time. She is proving to be more of a huntress than I ever imagined. She currently has three kills under her belt (four if you count the Gardner snake) since her arrival into the US. I don’t know what is more disturbing, that I have/had a minimum of three bats in the attic or that I am proud of little Aeisha for catching and killing them. Amazing really that she has these skills and very nasty that I have bats. Anyone know how to prevent bats from entering the attic?

*I was going to post a photo but after looking at them it makes me even more creeped out.