I have a mass of bees hanging from a tree in my yard. What are they doing?
Honey bees can pick the most interesting places to gather. Swarms are a natural division of the hive. They occur when the bee population becomes too large and congested in their nest. In response to the overcrowding the hive will rear new queens. Prior emergence of the new queens a portion of the bees, sometimes as many a 2/3's of the population, will leave with the old queen in search of a new nest site; leaving the remaining bees at the old nest site with a new queen. After leaving the old nest a swarm will usually gather on a tree limb, side of building, ground, or any convenient gathering site, as in your target. Scouts are sent out to find a new nest site. Once a new site is found the swarm will take flight again to that site.
The resting or scouting stage of the swarm may take a few hours or several days. Usually they will move on without encouragement. However, occasionally they will begin building comb at the resting site and not leave. It would not be advisable for you to disturb the swarm. Honey bees are venomous insects. They will sting to defend themselves. You should be cautious around the swarm. Allergic reactions to the venom from a bee, wasp, or hornet can be painful, even life threatening.
If the honey bees do not proceed to a new nest site within a few days you should contact a beekeeper in your area. There are two local beekeeping associations the Tidewater area of Virginia. Contact information for these groups is available from the "Local Groups" link on the VSBA website (www.virginiabeekeepers.org).