Any times, not always, the swarm does not want the empty hives that you offer. Perhaps any bees are very independent and want to open way, or perhaps they think, in a pride way, that the hive is small.
I would move the branch till the ball of bees falls from the top to the floor, and them they use the hive that you want. Other times I use a long reed with a bucket tied to catch it, I am very persistent. :evil:
The drum only in Carnival :-D, my neighbors would think that I am crazy playing the drum under a tree.