Mary and I watched them form this swarm in this Desert Broom in our back yard today. After they have rested the Queen they will disperse. In the meantime we are giving them a wide berth as they are very touchy when swarming.
Neat comp, Jim. Could be regular bees as well, but I'd still give them plenty of respect. My dad was a bee keeper for a while and I always hated when these things would swarm.