I was called on 24th June to see a swarm in 2 parts on a tree. The tree was on raised land next to the canal towpath in Jericho, Oxford. There was no hives nearby so I suppose it came from the Cripley Meadow Allotments which are reasonably nearby.
The swarm had formed in 2 places in the tree. By the time I saw it, it had joined into one fair sized swarm at the whippy top of the tree and was in accessible. Next morning it had fallen out of the tree and was all over the ground.
I put a box over the apparent centre of the swarm but the behaviour was very disorganised -- bees were fanning in different directions and moving very slowly to gather. There was also an area where bees were clustering about 2.5m away. I tried lifting them into the box but they wouldn't cluster properly. There were bees fanning but it wasn't having much of an effect. The bees which did go into the box coated the inside, rather than forming a lump.
After some mucking about I decided to leave the box with them to see if they'd get organised. I had lunch, had a nap, returned about 3 hours later. They were mostly in the box but there were still some on the outside. This was partly because I was using a box with vents. Ventilation is good once the bees are in the box but they often cling to the outside of the vents, attracted by the smell of the queen.
Eventually I got enough bees into a box to take them away. I tried to walk them into the hive during the hot afternoon but they stayed in the box. Again there was fanning in more than one direction. I left the box propped up against the hive entrance. Next morning they were still in the box. Hive lid off. Bang bang. Bees in the hive. It's a catch.
Even though most of the bees stayed in the box there was activity in the hive. I found evidence of comb building. This points to a possible explanation: this is a cast swarm with more than one unmated queen. Virgin queens have less strong aroma, which would explain the slow and disorganised responses of the bees. Multiple queens would explain why they formed 2 groups before I arrived, on the ground, and when I tried to hive them.