So how does one go about trapping feral swarms?
The simplest idea is to use "baited decoy hives," more recently identified as "swarm traps."
These boxes can be used nuc boxes, wood pulp containers, buckets, or whatever container you can devise. I've seen swarms take up residence in covered trash cans, dog houses, roof soffits, pool decking, hollow spaces in a studded wall, etc.
It seems the material is not that important, but you need to give them about 31 liters of volume, or roughly the cubic volume of a five-frame nuc box. If it's too small or too large, they won't move in. The opening should be about 1" in diameter.
It helps to elevate the bait box/swarm trap about eight feet in the air and insert frames of foundation. If you don't add foundation, the bees will immediately start drawing out come and then you'll find an intractable mess of comb, nectar stores, brood and angry bees.
You can bait the boxes with old comb, but this will also attract wax moths. The beekeeping supply catalogs offer little tubes of nasanov pheromones. These tubes, though they're costly, will more than pay for a swarm of honeybees when you compare the cost of the pheromone to the cost of a three-pound package of bees.
Traps themselves do not need to be expensive, and can either be purchased or made from a variety of materials. Here are some of my designs and uses:
Swarms like the one pictured to the right are more common than thought, and there are many swarms that are never noticed nor caught.
Since we've all missed our share of swarms that got away just minutes before we arrived at the scene, swarm traps offers an alternative to trying to shake them free.