Swarming is an entirely natural activity, and is the bees' way of perpetuating the colony by the old queen and her flying bees leaving to find a new home.  They wait a short distance from their old hive while they send out scouts to find suitable accomodation; during the summer, you may find a ball of bees hanging from a branch, or in a hedgerow, awaiting their reports before making a decision and moving on.  Usually, that's the last you see of them, but occasionally they may end up in a chimney or in other parts of buildings where they can cause a nuisance.
If you do find a swarm, please get in touch with us, and we'll try to come out to collect it.
Contacts in West Dorset
Bride Valley area  Ruth Homer  01308 482483
Bridport area Carole Brown 01308 456210
Bridport area David Smith 01308 423808
Burton Bradstock Colin Clark 01308 897412
Chideock and Westwards Sarah More 01297 489489

For other areas in Dorset, please contact the local associations.  You can find their contact details through the Dorset County Beekeepers Association website, and clicking on "Swarm Collectors" and "More Swarm Collectors"

If you'd like to know more about swarms, there's some information on the British Beekeepers Association website, including guidance on distinguishing between honeybees, bumblebees and wasps.