Swarm Control Secrets: Spot the Signs & Keep Your Bees Home

When a non-beekeeper hears the word “bee swarm,” no doubt the latest Hollywood movie depicting bees as a horrific plague of killer insects comes to mind.

But then there's reality: a swarm is simply honey bee nature at work perpetuating their species. When a hive swarms, the old queen and roughly half of the adult bees leave the hive and cluster on a nearby branch or surface, waiting to find a new cavity to move into. As beekeepers, we aim to prevent swarming, as it significantly weakens the hive. Let’s first explore how to identify a hive that is preparing to swarm. Here are some key signs:

1.      The Hive Is Overcrowded
Anytime the top box is more than 80% full of bees during spring or summer, there is a risk of swarming. If I observe a hive with all the boxes full, I assume it’s close to swarming. My next step is to check for swarm cells.

2.      The Bees Are Making Swarm Cells
As a hive prepares to swarm, the bees begin building swarm cells—queen cells usually found along the bottom or sides of a brood frame.

3.      A Beard of Bees Is Hanging at the Front of Your Hive

While this doesn’t always indicate a swarm, it can mean the bees are trying to cool the hive by reducing the number of bodies inside. Still, it prompts me to add another box and check for swarm cells if the hive is full of bees.

Fortunately, we beekeepers can use several effective methods to prevent swarming!

Prevention Strategies

1.      Providing Enough Space
This is the most critical swarm-prevention technique! Ensure the hive has ample room for expansion in spring and early summer. As a general rule, when the top box (brood box or super) becomes 80% full of bees in spring or early summer, add another box. Following this guideline will usually prevent swarming.

2.      Splitting
Splitting is a highly effective method to prevent swarming. Most beekeepers split their hives in spring to prevent large colonies from swarming.

3.      Adding a Medium or Shallow Box Below the Brood Boxes
Bees are much less likely to swarm if they have empty space under their brood boxes.

Unfortunately, simply removing swarm cells rarely works, and methods like trapping the queen inside the hive are ineffective as well. Prevention is truly the best option. However, sometimes, despite our best efforts, hives will swarm. If you notice swarm cells, it's time to take action.

Identifying Queen Cells

Many beekeeping books explain that swarm cells and supersedure cells (queen cells raised to replace a failing queen) are easy to differentiate. Swarm cells are typically located along the bottom and sides of frames, while supersedure cells are found in the middle of frames. While this is generally true, I’ve encountered situations where it doesn’t hold. Keeping that principle in mind, here are additional ways to distinguish between the two.

Swarm Cells

1.      Typically found along the bottom and sides of a frame.

2.      Common in overcrowded hives, where every box is more than 80% full of bees.

3.      Most often found in spring or early summer.

4.      Hive appears healthy, full of bees and brood, with a good brood pattern.

5.      Usually, 5–20 swarm cells.

Supersedure Cells

1.      Typically located in the middle of frames.

2.      Found in weakening or dwindling hives, which are not full of bees.

3.      Can be found at any time of the year.

4.      Hive often appears weak, with a poor brood pattern. Usually, only a few queen cells are present.

In summary, swarm cells are found in healthy, overcrowded hives preparing to swarm, while supersedure cells are found in weakening hives needing a new queen.

What Should I Do When My Hive Is Preparing to Swarm?

First, don’t panic! Everyone has a hive swarm from time to time. Though swarming reduces the strength of the hive, a strong colony can recover quickly. Next, assess how close your hive is to swarming. The best way to gauge this is by checking the swarm cells and evaluating the bee population. A hive typically swarms around the time when swarm cells are capped. This leaves a short window to intervene before the swarm happens.

If the swarm cells are capped, you don't see the queen, the hive seems to have lost a large number of adult bees, and you don’t see fresh eggs (new eggs stand upright in the cell, gradually tilting over until they lay flat on day three and hatch into larvae), it’s likely that the hive has already swarmed.

If you catch the hive before it swarms, you have several options:

1.      Split the Hive
This is the most effective way to prevent swarming. Once a hive decides to swarm, it’s challenging to change their minds! Splitting the hive into two or three new hives, each with a frame containing a swarm cell, not only creates new hives but almost always halts the swarming impulse.

2.      Wipe Out the Swarm Cells
This strategy doesn't always work well. Often, beekeepers miss a cell or the hive swarms anyway, even if all the cells are destroyed.

3.      Let Them Swarm
You can allow nature to take its course and then try to catch the swarm and place it in a new hive. This can be effective if the swarm clusters in a reachable location.

4.      Capture the Queen
Some beekeepers have limited success capturing the queen, placing her in a queen cage, removing the swarm cells, and adding a box to the hive. After about a week, the queen is released. While this may work, if a swarm cell is missed, the hive may still swarm with the virgin queen. This method can be just as complicated as making a split, with a lower success rate.

If we keep an eye out for the signs of swarming and act early, we can stay on top of hive management and keep our bees from swarming—or at least handle it better if they do.