HOWDY,  I have read, where I don't remember, about this, which also
included spraying water into a swarm - which might indicate to the swarm
an impending rain storm so should light till weather improved.  No water
close to swarm throw sand or dust into the midst to fool them of a dust
storm.  Or use a mirror to reflect the sun from a low angle - fool the
swarm of the sun going down, cluster till morning.  Communicate???
 
I don't chase swarms, if one is close enough to the ground, where I am I
will try to put it into a box.  We have close to 1500 colonies and
devides are too easy, also it is an effective remedy to swarming.
Splits plus some other timely manipulations will greatly reduce
swarming.  I said "reduce", not eliminate.
 
Richard -  -  -  Deep in the heart of TEXAS.