Watched a lecture given by Tom Seeley on UCTV about Swarm Intelligence in Honey Bees. Excellent presentation! He has a follow-up lecture titled _The Flight Guidance Mechanisms of the Bee Swarm_too.....As well as other interesting topics. I strongly recommend these lectures, You won't be disappointed!
Bottom line for the beekeeper baiting for a swarm: Fifteen bees at the lure entrance at one time is a threshold that will likely result in the the swarm choosing that particular location. 'Quorum Sensing' is just one of the interesting terms he introduces (Vox Populi is another), and it has some crossover to the human organism too. An excellent communicator!