We have a colony of bats that live in our chimney (I think). A guy I work with (who is big into wild animals) said that they are probably Brown Bats? Anyhow, I see them in the spring and summer at dusk when they swoop down to pick up bugs. (Keep up the good work, batty boys and girls.)
Seriously, I do not mind them at all except when they get into our house (which has happened probably about 5 times over the past 10 years) because it freaks out our birds. And my mother-in-law. I just get them in a room where I can close the door, get a towel and drape it over them and then release them back outside.