I've been asked about the Round Rock bats. I saw a swarm in my way home, and circled around, hoping to get to a good stopping place before it was all over.
That bird is a hawk, and it was lying in wait for the bats to come out. I saw it catch at least four in the maybe twenty minutes I was out there.
Wave upon wave of bats, flying out from under the bridge, a swarm like this maybe every ten or fifteen seconds. I stayed and watched for, as I said, about twenty minutes, and the exodus was in full swing when I got there, and barely started tapering off before I left. The sheer number of the bats is mind-boggling.
Here are some just emerging.