So on the weekend, I built my hive a stand and erected a small sail to keep it in at least partial shade throughout the day. The bees were a bit miffed when I moved their home onto the stand, but seemed to do OK on Sunday. At this point of the season they were busy working on the Flow super. Most of the cells have nectar in them, and about 30% are capped.
I came home after a hot day today (37C), and I can barely see any bees in the super. There are still bees coming and going from the hive, but where the window used to be covered in bees, there are probably only 10 or 20 visible in the window now.
Any ideas why? Could the colony swarm this late in the season (it was a colony I caught as a swarm about 7 weeks ago)? Could it be that I accidentally put the brood box back on the stand back-to-front? Have they all just moved down into the brood box?