A swarm is a softball to basketball-sized cluster of bees. Swarms are groups of bees led by a queen that have left their original hive to start a new one. If left alone, in most cases they will move on within a few days once they find a new nest site. Nests are usually identified when people notice large numbers of bees coming and going from a hollow tree or other natural or artificial cavity. All bees will sting to defend their nest.
Honey bees are beneficial insects.
They are essential for pollination of many of California's native and crop plants. If the swarm or hive does not pose an immediate threat to humans it may be best to leave it alone. A technician will try to respond by the next working day. We cannot treat hives or swarms that are inside a wall or other structure. Attack could last until the victim vacates the area.