There are two main types of swarms: overcrowding swarms and reproductive swarms.
An overcrowding swarm happens when bees feel overcrowded in their space, they are more likely to swarm. A few main causes of an overcrowding swarm are:
Problem: Nectar being stored in the brood nest.
Solution: add supers to give the bees more space.
Problem: Honey or pollen in the brood nest, preventing the queen from laying
Solution: remove frames with honey, add empty frames. The bees will get to work on drawing comb and this will give the queen room to lay eggs
Problem: Too much traffic congesting the brood nest
Prevention: use a top entrance to give foragers a way in without going through the brood nest.
Many beekeepers think that simply adding a super will keep their bees from swarming in the spring, but this is not always the case. While the bees do appreciate the extra space for honey storage and to relieve congestion, but when it comes to the second type of swarming, which is a reproductive swarm, an extra super may not make a difference.
In the spring, when the flowers and trees begin to bloom and bees begin to bring in more pollen, they also naturally begin to rear more brood to build up their colony for the season. All these new bees require food, so they begin to eat their remaining honey stores from the winter.
As the bees eat, the honey stores deplete, which make more and more room for new brood. But when the bees reach their own determined limit for brood, they’ll begin to stop the queen from continuing to lay eggs by producing and storing honey in the brood nest once again.
Once the brood nest is mostly full of honey, they start to build swarm cells. Once those cells begin to be capped, it’s at this point that the queen decides to leave the hive with a large number of bees with her. At this point, even if you catch your swarm, the hive has stopped brood production and is down a large number of bees. You will be hard pressed to have this hive make honey. The remaining bees may swarm on their own, following one of the virgin queens.
If you notice your bees preparing to swarm just before the main nectar flow, we recommend splitting your hives.
Some beekeepers choose to do a split with the old queen, and keeping all but one frame of the open brood. Leave the old hive with the capped brood, one frame of eggs/open brood, no queen and empty supers. This helps prevent new swarms because the old hive won’t swarm without a queen and the new hive won’t because they have no foragers.
Obviously, the easiest thing to do is watch your hives carefully and prevent a swarm before it starts, rather than managing it after it’s too late.
Opening the Brood Nest
One of the easiest ways is to keep the brood nest open and keep it from backfilling, keeping those nurse bees busy. If you catch it before they start queen cells, you can put some empty frames in the brood nest, sandwiched between 2 frames of brood. How many empty frames you add depends on how built up your cluster of bees is, since those empty frames need to be filled with bees and comb. Once your queen finds this new comb, she’ll begin laying eggs. This new open brood nest gives the nurse bees something to do, which is build comb then attend to brood, while expanding the brood nest.