Why Bee Swarms Appear Around Homes Seeing a large group of bees gathered on a tree branch, fence, or the side of a house can be surprising for any homeowner. In many cases, this is a natural part of the bees' life cycle known as swarming. A swarm forms when a colony becomes too large and a queen leaves with thousands of worker bees to establish a new home. Homeowners often contact a Bee Swarm...