Do you have a swarm of bees on your property?
Swarming is an instinctive part of the annual life cycle of a honeybee colony. It provides a mechanism for the colony to reproduce itself. Bees in a swarm are generally docile and not inclined to sting or attack, and they will usually leave within a few days on their own for a more permanent location.
However, if you have a swarm that has permanently settled, or you are anxious to have it removed, you can contact a local beekeeper who may be able to remove the bees without killing them.