A swarm is a natural phenomena in which honeybees will fly away from their present hive in search of a new home, often landing as a cluster of bees on tree limbs, or on bushes while searching for suitable housing.  This is usually prompted  in response to one or more of the following conditions ...

• A natural instinct to reproduce ( The old queen leaves with the swarm , and a new queen will emerge from brood left behind inside the original hive thereby creating two separate colonies.
  
• Overcrowding...  A strong colony may contain as many as 60,000 honeybees during the heat of the summer which leads to congestion especially within the brood chamber.
  
• Excessive hive temperatures... In order to raise the young honeybee brood, the internal temperature of the hive must be maintained within a few degrees.  Hives located in direct sunlight may be particularly difficult for the bees to maintain or cool properly.
  
• Smoke and Fire ...   Honeybees if alarmed by smoke or fire will first attempt to engorge themselves with honey prior to fleeing as a swarm from the heat and smoke in order to be able to establish a new hive should their present home be destroyed.

First, relax !  Honeybees clustered in a swarm are usually very calm and will not normally sting unless provoked.  However, as a precaution, you should keep everyone, including pets and animals, back at least 75 feet from the swarm.  You should not attempt to spray the swarm with any insecticides or attempt to capture or destroy the swarm yourself in any way !  This must be left to professionals.  Next, call a St. Clair Beekeeper as soon as possible so that he or she can make arrangements to remove it to a safe new home.