To definitively answer my own question:
YES a swarm is possible.
My hive swarmed. Robbed out what nectar was in the flow frames almost completely and a least half the hive left.
Unfortunately due to the terrain, I was unable to capture the swarm.
My best guess as to what happened based on a post-swarm inspection of the hive:
- abundant resources caused the foraging bees to store in the brood box
- hive workers were unable (unwilling) to wax/work the flow frames to keep up with incoming resources
- hive population was high
- queen ran out of room to lay and the hive decided to swarm out
On inspection, there are some partially formed queen cups mid-frame, and a couple of partially formed swarm cells on one frame. There are no capped queen cells, so it seems like the decision was made hastily.
In the brood box there are a few solid frames of capped honey and pollen (either side)
There are 2-3 solid frames of capped brood, some uncapped brood varying stages, and a small number of eggs. In the middle of the brood (frames 3 and 4 in the 8 frame brood) there are big patches of open nectar and pollen with a little bit of uncapped young larvae around the edges.
I’m not sure yet what the lesson from all this is. It’ll take some time to process I guess.
Would I have spotted a problem if I’d opened the hive a few days ago (as I was thinking of doing)?
What could I have done to avoid this situation? Remove some full frames at the last inspection from the brood to keep the brood space more open for the queen? But at that stage the super had only just gone on, and the hive had only just started working in it. I had no idea they would be slow in the super!
Could/Should I put on and ideal/deep super with foundation frames on top to free up space used by resources in the brood?
What’s to stop the same problem occuring again once I have a new queen and the hive population is growing again? Is there anything else I can do to encourage the bees to work the flow frames? Or will this just happen again in 5-6 weeks?
My mentor gave me generally sound advice (I think). “There’s space, let them be bees and do their thing. They are not likely to swarm.” I trusted that advice, but I think it is perhaps less valid for a flow hive if there’s evidence that the hive is very slow on working the flow frames.
I’d really love to hear the Flow community’s collective wisdom here. I realise that every hive/situation is subtly different, but I feel there’s learning to be had here and I’m keen to learn if I can.