A natural instinct of a bee colony is to swarm and leave its hive to establish another colony elsewhere. This is the way that bees increase their numbers to survive as a species.
Swarms normally occur in the spring and early summer months. When bees swarm, they move out of the hive and fly to a new temporary location on a post, tree or fence in your backyard.
Once the swarm of bees has landed and settled, it clusters into a tight ball, which can vary in size from 200- 600mm in diameter. The bees will stay in this temporary location until a new permanent home is found and then the whole swarm will fly away again.
Is a Bee Swarm dangerous?
Swarming bees are not likely to attack and sting unless they are provoked by some sort of interference. There are a couple of reasons for this docile behavior.
While they are swarming and are temporarily settled, there are scout bees out looking for a new home and in their minds the swarm does not have a home to protect, so defensive behavior patterns are suspended until the new home is found. Another reason swarm bees are docile is that they leave their original home with bellies full of honey and this limits their lower body movement making it difficult to successfully sting.
If a swarm of bees arrives at your house, stay inside till the swarm has clustered and most of the bees have stopped flying. Watch for foraging bees flying to and from the swarm, as they may not see you and could get caught in your hair or clothing.
When you go outside, wear footwear to protect your feet in case some bees have landed on the ground.
What not to do
Do not attempt to move the swarm by hosing it, throwing stones at it, or poking it with a stick. This action will only aggravate the bees and encourage them to sting in defense.
It is safest to not attempt to remove a swarm yourself unless you have experience in handling bees.