Hi, Ibrahim.  You can force swarms to self-retrieve by
simply putting a queen excluder between the bottom box
and the bottom board.  Any swarms will be back in the
hive within 2 hours after finding they don't have and
egg layer with them.  If you do this, though, you must
go through the hive frame by frame every 10 days to be
sure the bees aren't trying to raise new queens.  With
the QE below, new queens can't get out to mate.  Dan

__________________________________________________
Do You Yahoo!?
Yahoo! Photos - Share your holiday photos online!
http://photos.yahoo.com/