I recently had the opportunity to see a swarm of honeybees in a tree. It was pretty impressive: a ball of living honeybees about a foot across on a branch a few feet overhead. A few bees were coming and going to and from the swarm. These bees are scouts that leave the swarm in search of a good place for a new hive. When a colony reaches the size where it needs to be divided an egg that will become a new queen is nurtured. Sometimes, even before the new queen has hatched, the old queen will leave the hive with a swarm of workers in search of a new hive location. The swarm gathers and awaits the finding of the new location. The new location may be in a hollow tree, building cavity, or other protected place. Beekeepers can collect these swarms into a manmade hive for pollination or honey production.
Once a swarm leaves the old hive and moves to its temporary location, it will stay there until a scout finds a new spot. This can take anywhere from a few hours to a week or so. For the first couple of days, the bees in the swarm are very docile and this is the best time to try collecting them. After that, they have been without food long enough to be a bit testy and are more likely to become agitated and sting.
If you do see a swarm of bees, you should do one of two things. One is just leave them alone. Honeybees are important pollinators and their population is decreasing significantly due to several problems in many areas so it is important not to become alarmed and kill them. If you would like the swarm removed, you can contact a bee specialist who will be glad to come and collect them. Contact information for the Connecticut Beekeeper’s Association is available at their website. More information on honeybees can be found at the Connecticut Agricultural Experiment Station website and at the UConn IPM fact sheet on bees and wasps. A great general reference on honeybees can be found at the National Geographic website.