Bee swarms usually occur during spring but can take place any time of the year if conditions are favourable.
A swarm happens when the queen bee and thousands of workers bees leave the hive in search of a new home.
Swarming bees, once they have settled down, are very docile and are not inclined to sting provided they are left alone, and several common-sense precautions are taken.
Many bees will be flying around as the swarm forms. Keep children and pets inside for half an hour or so, until the flying bees have clustered on to a bush or other object.
Once the swarm has formed a cluster, and the bees have stopped flying, it is safe to be outside at a sensible distance. Keep your shoes on in case you step on the odd bee that has settled on the ground.
Do not hose the cluster with water, throw stones at it, smoke the bees or take any action to encourage the bees to move, as this may provoke the bees to become aggressive.
Swarms will relocate to their new hive within 1-3 days.