Anchorhead said:

Keep us posted.

They keep doing it, and every single time it is on a day that goes from sunny to cloudy to stormy (which is happening a lot here lately). They start to swarm at the very beginning of the cloudy interlude, but usually with enough time to notice and recapture them before the rain hits.

One day he had just finished catching a swarm and got his bee gear put away, when another hive started to take off. He's never seen anything like this before, and the bee books we have don't seem to cover exactly what we are experiencing.