Same bees, nine hours later

At 10 p.m. and 50 degrees, the swarm is hunkered down for the night. At first light the scouts will head out again in search of a suitable home. It may be a hollow tree or an attic.

If a scout finds another hive in a good location, it will make multiple attempts to get inside. The bees there will drive it off, but eventually it will pick up enough of their scent that it will be able sneak in for a look around to gauge the hive's strength. If it is weak, the swarm may try to take it over.
But tonight they huddle together around the queen in a solid, vibrating mass, trying to stay warm. It will probably get down to about 40. The bees will keep rotating position so none spends too long on the outside.
They mostly keep their heads pointed in, but the flash so close disturbs them a little. This picture is taken from about six inches away. I've left it large, so if you click on it you can see it full screen.

I called a co-worker who just started keeping bees, but she wasn't really prepared to come get them. My neighbors were still up, so I got them to come out and look. "Cool!" was the consensus.