Looking at one of my hives, there were lots of orientation flights going on yesterday. The other hive was relatively quiet. Why?

Let me give some details. The busy hive holds a swarm that I captured 9 days ago. It is a TBH. They have been building comb like crazy, but there is obviously no brood hatching yet. It is equally obvious that since this is a captured swarm, all the bees have been out flying at least once. The second TBH has a swarm that has been hived for just 4 days.

I have a few sort of related theories. One is that the bees feel like they have built enough comb to meet their immediate needs and now they need to fill those combs with honey and pollen, so they are switching from comb building to foraging.

The second theory is that brood is capped, and there is less work for the bees to do inside the hive, so they are foraging.

The third theory is that the big honey flow is over from the fruit trees and they need more foragers to provide food for the colony.

My favorite theory is the first one. The second theory seems unlikely because there should be just as much brood to cap tomorrow as there was today and yesterday. The third theory is OK, although I though the main honey flow continued well into May usually?

Anybody have any other ideas or can you tell me if any of my theories are correct?