One very important difference between the two varieties is the ultra defensive behavior AHBs can display while protecting their hive. In some South American attacks, AHBs have seriously stung or killed pets, livestock, and humans. USDA inspectors sprayed the swarm, but some bees dispersed. Although there is no evidence that these bees survived and become resident in this area, it is possible that AHB could arrive at any time either by migration from the south or by hitch-hiking in a ship, truck, etc. coming from a colonized area. 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.