What is a swarm?
In late spring and early summer, honeybee colonies reproduce by swarming. The old queen leaves the hive with thousands of worker bees, and they gather in a cluster, often on a branch, fence or wall, while scout bees look for a new home. This cluster can stay for a few hours or a couple of days.
Are swarming bees dangerous?
Swarming bees are usually very calm because they have no nest or young to defend. Keep children and pets away, do not disturb the cluster and do not spray it.
What to do
- Keep people and pets at a distance and close nearby windows
- Check it is honeybees, which are golden-brown and form a large cluster, not wasps or bumblebees
- Find a local swarm collector through the British Beekeepers Association swarm collector map on its website
- A beekeeper will usually collect the swarm and rehome it
If bees move into your building
If the swarm moves into a chimney, wall cavity or roof space, it becomes harder to deal with. A beekeeper or specialist may be able to remove the colony. Treatment is only considered as a last resort where bees cannot be removed safely, and the entrance then has to be sealed so other bees cannot rob contaminated honey.
Bumblebees and masonry bees
Bumblebees do not swarm. If you have bumblebees in a bird box or under a shed, leave them alone; the colony will die off by the end of summer. See wasps or bees? for identification.
Questions and answers
How long will a swarm stay?
Usually a few hours to two days while scouts find a new home.
Will you kill a bee swarm?
No. Swarms should be collected by a beekeeper.
Who do I call for a swarm in London?
Use the British Beekeepers Association swarm collector map to find a local volunteer.
Related pages
This page is general information, last reviewed on 19 October 2026. It is not a substitute for an on-site inspection.