One of our colonies in the bee shed swarmed last week. The swarm ended up clustering around the entrance to the hive it had ‘escaped’ from. It was captured and rehoused successfully. The swarm in the picture is up to 5cm deep in places and probably contains 10-15,000 worker bees … and a single queen bee.
Swarming is the natural way that a honey bee colony ‘reproduces’. The old queen and all of the older foragers leave the hive to establish a new colony. The remaining workers raise a new queen from an egg or young larva in the original hive, so generating two colonies from one. Swarming usually occurs in late Spring or early Summer.