Swarming is the honey bee’s natural and instinctive method of reproduction and dispersal, and so is hard for beekeepers to change. The most common type of swarming is where one colony buds off another and the parent colony continues in existence. Another kind of swarming is absconding, where a whole colony deserts a hive. This is much less common in New Zealand.

Most swarming occurs from late September to early December, before the main honey flow when large amounts of brood are being raised, the adult population is increasing rapidly, and food supplies may be erratic.

There is no single cause of swarming, just as there is no single method of swarm prevention. Swarming is stimulated by a complex combination of factors, none of which on its own will usually cause swarming.

• a reduction in output of queen substance or pheromones, by the queen, usually because of aging
• an increase in colony size
• congestion in the brood nest interfering with transmission of pheromones,
• a drop in the average age of workers as the colony expands quickly
• rapid influx of nectar and pollen
• genetic makeup of the colony (some strains swarm more than others).

It is far better beekeeping to prevent swarming preparations from being made, rather than try to stop a swarm from leaving the hive, but swarm prevention techniques must be compatible with profitable colony management. There are a number of management systems described as swarm control techniques, most of which are very complicated. A good swarm prevention method must reduce swarming with as little interference to the colony as possible.

Some of the better swarm prevention mechanisms include:

• regular requeening
• providing room in the brood chamber
• providing room for honey storage
• ensuring adequate ventilation
• using non-swarming strains
• artificial swarming
• interchanging hives

Despite the best intentions, not all beekeepers have swarm prevention completely up to scratch, and occasionally remedial control measures have to be taken (such as cutting out queen cells when swarm preparations are detected), but these must not be regarded as a substitute for good prevention.