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Do bumblebees swarm?

No, bumblebees don’t form swarms.

If you see hundreds or thousands of bees flying close together or tightly packed on a surface, these will be honeybees. Please seek advice from a local beekeeper.

If you have a Tree bumblebee nest nearby, you might see 10 to 20 bumblebees flying around in a little dancing cloud outside a nest entrance, especially if it’s in a bird box or somewhere else above ground. These are male bees who are waiting for new queens to emerge so that they can mate with them. Male bumblebees cannot sting, and they pose no risk to you at all. This behaviour is one of the later stages of a Tree bumblebee nest, so if you see this happening, the nest will probably only be active for a few more weeks.   

Discover more about Tree bumblebees in our Bumblebee species guide and this Introducing the Tree bumblebee blog by Trust volunteer, Clive Hill.

This video shows the ‘swarming’ behaviour of the Tree bumblebee (Bombus hypnorum). This common behaviour is called nest surveillance and happens when male bees dance outside nest boxes, waiting and hoping to mate with virgin queens as they emerge from the nest. This activity happens mainly in May, June and July. It can occur over most daylight hours and may last several weeks. Video by Clive Hill.