I set the video camera on night vision pointed at the hummingbird feeder on August 1, 2013 from 8pm to 9pm.
The first 9 minutes all you see is a “blur” until the first bat takes a drink. By 8:30 pm there are multiple bats feeding. We have seen 40+ bats at once as they set off the motion lights at the visitors center.
We have stood in the dark and let them fly all around us as they feed. We can hear and feel them fly by. We have yet to be hit by one, but did hear one hit the wall.