Signs that the bees are about to swarm
There are several things that indicate that a colony might swarm:
1. They start to produce queen cells
2. There is no more room in the brood box
3. Clusters of bees appear near the entrance of the hive
When a hive is filled with honey and has no room for new eggs, worker bees search for a suitable place to set up a new colony. After the queen has mated, she takes about half the worker bees and starts a new colony in the new location. A new queen is left behind with the other half to continue the old colony.