Do you see bats were you live?

I used to have an office in the main administration building on campus, up in the top floor. One day, I come into work and see something stuck on the brick wall. A closer look showed it was a bat clinging to the wall. Apparently the attic of the building, right above our heads, has become the nesting grounds for a rare species of bats, and sometimes, they get down into the offices below.