Honey bees propagate their colonies by dividing. Typically, once a year they produce a new queen; and the old queen will fly away in a swarm with more than half of the bees. Swarming reaches its height in the spring. For the beekeeper, the loss of a swarm of bees usually means the loss of that hive’s honey crop for the year. If the beekeeper can catch the swarm, it can make for an additional bee hive. Beekeepers can place bait hives out to provide attractive cavities for swarming honey bees. Not only do they serve to capture one’s own swarms, they also catch passing swarms from feral colonies. Bait hives can be placed anywhere, but they are most effective if they are located 10 to 15 feet above the ground. One style of commercially-available bait trap resembles a fiber flower pot. It can be baited with a packet of queen pheromones. I have used these traps with some success. If you find the swarm of bees shortly after they moved into the trap, you can pour the bees into a hive. If the bees have been in place for a while, they will have built comb which can be placed into hive frames.
We often hear of swarms of bees moving into the walls of houses. After they are removed, it is not uncommon for a new colony to move into the same location if the old comb is not removed. I like to place bait hives which work similarly in my bee yards. These are simply hive bodies holding old comb that I have removed from hives in my comb replacement rotations. The old honeycomb is quite an attractant to the scout bees of swarms. Scout bees can often be found investigating these comb-filled hives soon after they are placed. They fly a rapid zig-zag pattern at the bait hive entrance. In the picture, a brown-colored hive serves as a bait hive in my queen evaluation bee yard.