@hark
Yes, the time is correct. We got to the bridge around 7:30 and waited until the first scouts came out. The sun was just behind the mountains. My initial capture was an iPhone movie that is time-stamped at 7:49, which right after they started emerging en masse. Sunset is about 7:45.
It was spectacular, and what was surprising is that they came out in waves. Just when we though they are about all out, more flew out, and that happened several times.
We have bats in my neighborhood, and they start flying at about sunset. So, if you are looking you need to be out a little before sunset.
EDIT: My camera clock was off by 50 minutes unless I accidentally changed something while trying to figure out my settings. So the metadata shows 19:00 17.25, which is about an hour earlier than when I actually shot the image.
I had opened up my aperture a lot and didn't change it for this image, so way way way over exposed, and lack of focus. So, there you go. Live and learn. Shows how much you can recover using RAW data.