Last week I was in southwestern France and spent an
afternoon with a French beekeeper.  Mirabile dictu, a swarm
appeared suddenly in a poplar nearby.  The beekeeper
began clapping his hands together sharply for about 30
seconds.  Then he switched tobanging  two pie tins for
another minute. He said this would bring the swarming bees
together.
     In three minutes the bees had assembled on one limb
we retrieved the swarm and hived it without incident.
     I've never seen this done before.  Is it sound biology or
French wish fulfillment?