Bees ran out of space and have swarmed. There will be queen cells in the brood box. Do not look for them. In 10 days, do an inspection and look for opened queen cells. The bottom will be an almost perfect circular opening or maybe with a flap. Then close the hive back up and do not go into it for another two weeks. Once you see eggs, indicating a returned mated queen, consider adding a second brood box.
There are various methods for getting swarms out of trees depending on how high up they are and how big the branch is they are clustered on. The reality is that unless you can reach them with a ladder or entice them into a swarm trap, they are lost to you.
Bees swarm when they feel they are strong enough to create another colony. Unfortunately, they base this in part on how crowded they are. When the entire colony moves out, that is an abscond. Rarely happens once a colony is established in their hive. In the fall, what appears to be an absconding is bees dying from varroa related viruses.
There are various methods for getting swarms out of trees depending on how high up they are and how big the branch is they are clustered on. The reality is that unless you can reach them with a ladder or entice them into a swarm trap, they are lost to you.
Bees swarm when they feel they are strong enough to create another colony. Unfortunately, they base this in part on how crowded they are. When the entire colony moves out, that is an abscond. Rarely happens once a colony is established in their hive. In the fall, what appears to be an absconding is bees dying from varroa related viruses.