The honey bee lives in an organised society. The individual bee is not able to reproduce as a single insect so has developed a technique of mass reproduction or colony reproduction. During spring as the weather warms, pollen and nectar become abundant and the population of the colony increase rapidly. There may be 50,000 to 60,000 occupants.
The bees start by building queen cells to raise young replacement queens. A few days before the first queens are due to emerge; the old queen with about half the workers and drones leave the hive in search of a new home. As the workers leave they fill their stomachs with honey. This is their food reserve and enables them to construct their new home made of beeswax. Flying in what looks like chaos, they usually cluster on a tree close to the parent hive. This is known as a swarm.
Once settled, scout bees scout the area looking for a new suitably sized home such as a cavity in rocks, a hollow tree, wall cavities, a compost bin or possum box. Once found, the swarm proceeds directly to it.
Over the next few days, the bees construct comb from wax they secrete allowing the queen to lay. By resuming their foraging duties for food they increase their chances of surviving through winter. The swarming period is spring and early summer giving the colony the best possible chance of survival.
But for the beekeeper swarms diminish the honey gathering capacity of the colony. They create fear amongst neighbours and a nuisance to local councils. A reasonable amount of effort should be taken in swarm prevention.