A swarm guard is similar to a queen excluder except it is designed to fit over the entrance to a hive. Just like a queen excluder, it prevents both queens and drones from passing through because the wires are close together. Worker bees are small enough to pass through easily.
Swarm guards have their uses but they can only be used for short periods in particular circumstances. If they are left in place for too long, they can produce disastrous results. For example:
- Since drones can’t get in or out, the ones outside can’t return home and the ones inside can’t leave. You can get hundreds of dead drones piling up behind the guard until the entrance becomes virtually blocked to the workers. The workers can’t remove the dead drones either, so you are left with a big mess.
- A swarm guard will prevent swarming for a time, but its presence won’t stop the swarm impulse. Eventually, the swarm may leave with a virgin queen that is small enough to fit between the wires.
- If you put the guard on when a virgin is getting ready to mate, she may not be able to get out. Or if you put it on when she is already out, she may not be able to get back in. In either case, you are creating a queenless hive.
But it’s not all bad
Nevertheless, swarm guards can be useful tools. I use them sparingly for the following purposes:
- Swarm guards are useful when installing new packages. Since the queen can’t leave the hive, the colony is unlikely to abscond with a swarm guard in place. I usually leave the guard in place until the new queen is laying eggs. Since there are no drones to get caught behind the guard, and you have a mated queen on the inside, it is safe to leave it on for a few days.
- If I happen to see a colony that is itching to swarm, I install a guard immediately. This stops the swarm from issuing long enough for me to gather equipment and set up a split. I’ve been able to forestall many swarms just by having one of these devices on hand. If I can’t do the split the same day, I take off the guard before dark so the drones can sort themselves out, then I do the split first thing the next morning.
- During fall and winter when no drones or queens are coming and going, swarm guards can be used as mouse guards. Still, you have to remember to take them off before drones appear in the spring.
I’m sure other beekeepers have found creative ways to use swarm guards. Let us know what you do with them.