The bat is back!

I shone the flashlight up into the bat house before dark, and it's occupied! A single bat. It is exactly 1 year to the day that we put the house up. We discovered the first (and only) occupant last year on June 15, and it remained only two days. So maybe it remembered and has come back to roost for the summer. I want a whole colony (it is a nursery-capacity house), but I'll settle for one. Tomorrow I'll lay out a white towel or sheet underneath the house so I can monitor occupancy by checking for guano. I don't want to disturb any occupant(s) too much with a flashlight. But it's soooooo tempting.