Fairly new to the beekeeping hobby, only been in one year. In that time I've successfully caught two swarms out of our apple trees. A swarm is a group of bees that, for whatever reason, has taken a queen and fled from their hive. When they leave they'll leave queen cells and enough workers and drones to care for any brood that is in the hive. The workers left in the hive will take care of the brood including the new queens and the drones will mate the new queen.
Here's swarm one:
Borrowed equipment since I didn't own any extras at the time:
Moved that swarm into their new home:
Swarm two catching and new home:
I really do enjoy this hobby. I hope to catch many more swarms and keep this hobby cheap. I really appreciate the free bees.