Swarming is how honeybees reproduce. The bees will raise a new queen in the hive, and once she is safely developing, half the bees will leave with the old queen to set up home somewhere else, usually a mile or so away from the original location. They will settle up outside the hive before they leave for good, and take pit stops along the way as the queen does not fly that well and they need her in order to start the new colony, being the only member who lays eggs. Once they’ve found a suitable cavity, they will quickly establish new wax combs and thus, a new colony is ‘born’.
Bees swarm from April to July, with the main month being May. The bees mass together to protect the queen, and are not aggressive as they are focussed on finding a new place as they are very vulnerable outside their hive. You may see them flying, or settled in a cluster but either way, this is completely natural and healthy behaviour.
When swarms are in a cluster, they can be collected. They can settle for a half hour or so right up to a couple of days, and so please do contact a beekeeper as soon as you spot them, as they can be put in to a skep or box and then at dusk, taken to a hive where they will make their new home.
Swarms can occur in all shapes and sizes:
It is ONLY honeybees that swarm, and that can be collected . It is important to collect them as they will happily go in to chimneys or walls and not everyone wants that – although many people live perfectly well alongside bees in their property. The best way to find someone to remove them is to ring your local council or search online for a swarm collector.
Bumblebees and solitary bees do not swarm, but at the times when the virgin queens are emerging, there will be many males around too and this can look like a swarm.
I am very happy to assist with advice on bumblebees, or there is this excellent FAQ from the Bumblebee Conservation Trust.
Solitary bees cannot be moved, but their activity period is so short lived it can be easily accommodated so that these essential pollinators can undergo their life cycle.