Why Bees Swarm – Bees & Beekeeping Information

why bees swarm

The word "swarm" is most commonly associated with honey bees, yet this natural and complex process is not commonly understood.  Why is this a common behavior among bees and what purpose does it have for the honey bee population? Let's find out more about why bees swarm.

What Are Bee Swarms?

Before we get into why bees swarm, what exactly is a bee swarm? A swarm is defined as a dense group of insects. Consequently, swarming is a natural process in the life of a honey bee family group, which is known as a colony. A successful colony of honey bees includes three common types: workers, drone and a queen. Each type of bee plays an important role to maintain a successful colony and to allow for the reproduction of the bee species.

swarm of bees

Types Of Bees

Worker Bee



Bee Swarms

​​​​​Many people wonder why bees swarm. Swarming occurs when a large group of honey bees flies away from an established colony to establish a new colony. During a prime swarm, the majority of the worker bees will exit the original hive with the old queen. A swarm can be populated by thousands to tens of thousands of bees and commonly occurs in the late spring and early summer.


The process does not spontaneously occur. Rather, it is a carefully orchestrated event that follows a set chain of events. Workers create cups for the queen to lay her eggs in throughout the year, although, the queen will only lay eggs in them when a swarm is imminently approaching. Laying an egg in a queen cup signifies that the queen is planning to leave the hive while also preparing her successor.

While the new queens are being raised, the workers reduce the feedings of the departing queen to lighten her and to stop her from laying eggs. This prepares her for her upcoming flight when leaving the hive. During this time, there is a gap in the egg-producing of the colony, and the swarm can begin when the queen cells are capped and before the new queens leave their cells. Meanwhile, scout bees will find a location for the swarm to descend upon.

The Swarm Event

After the preparation is complete, the swarm will begin. Upon the first emergence from the original hive, the swarm occurs nearby, usually at a branch or tree meters from the hive. This nearby location is not the permanent stop for the new nest, but rather an interim location for the cluster while scout bees scour for the new location. This process usually takes a few hours and the rest of the swarm clusters about the queen to protect her during her temporary stay. However, in rare instances, this process can take up to three days.

When the ideal location is selected, the swarm will fly to the new location and begin populating the new home. This group of bees is known as the "prime swarm." Meanwhile, at the original hive, the new queen will soon emerge and will kill her unborn sisters with the assistance of her worker bees.

colony of bees in a hive

Why Bees Swarm

There is a fairly simple reason to why bees swarm.  Swarming is a natural and critical occurrence in the life of bees and occurs for two main reasons: space and a method of reproduction.

A Solution For Space

Just as humans find solutions to prevent overcrowding such as moving or decluttering, honey bees also take action. When a colony outgrows the capacity of its home, they swarm in order to find adequate space.


Swarming also serves as a colonies' method of reproduction. During the swarming process, one colony splits to form two or more colonies thus propagating the species.

How to Avoid Bee Swarms

For beekeepers who do not wish to increase their number of active hives, there are many methods to prevent the swarming process.

boy chased by a swarm of bees
  • ​​Clipping the wing of the queen: By rendering a queen unable to fly, the swarm will move right outside the original hive making it easy for the swarm to be contained.
  • The Demaree Method: In the Demaree Method, a frame of capped brood is removed with the old queen and put into a hive box with frames and foundations in the old hive. Next, a honey super is added to the top of this hive topped by an inner cover. The remaining hive box without the queen is inspected for queen cells, and queen cells are destroyed. This hive box, where most of the bees are, is moved to the top of the crown board.  Bees in search of food will return to the lower box and will deplete the population of the upper box. After a week or more, both parts of the hive are reinspected and any remaining queen cells destroyed. After this process, the need for swarming is eliminated, and the hives can be re-combined.
  • By keeping the brood nest open: During the swarm preparation process, worker bees populate the brood nest with honey. The queen stops laying eggs to be slim enough to fly, and the nurse bees follow her. By employing this method, the brood nest is opened, and the nurse bees encourage the queen to lay eggs again. This is achieved by a number of slight modifications including the presence of empty frames in the brood nest, bare foundation or drawn combs in the brood nest, or by relocating brood combs to the box above to encourage further expansion of the brood nest.
  • Checkerboarding: During the late winter, worker bees re-arrange frames above the growing brood nest. These frames consist of alternating full honey frames and empty drawn out frames or foundationless frames. If a colony does not have enough reserves, it will not swarm. Checkerboarding these frames above the brood nest achieves this by removing the sense of having reserves.

Beekeepers may also be called to capture swarms that are established by wild honey bees or from the hives of beekeepers.  The process is commonly performed with a bee vacuum that will capture the bees in a container so they can be moved to a new hive. If performed correctly, few bees are lost. The collection and relocation of bee swarms is almost always possible, meaning that extermination is rarely necessary and frowned upon given the vulnerability of the bee population.


Now that we understand why bees swarm, it's important to understand what to do when you see a swarm.  While the sight of a swarm of 10,000 honeybees can be unsettling, both scientists and beekeepers urge the public not to kill the bees or disrupt their hive. Those who happen upon a swarm can take comfort in the fact that bees are at their most docile during the swarming process as they have no nest or honey to protect. Unless they are provoked and feel that they are being intruded upon, they will not attack.

Also, it is important to understand that the swarming process is temporary, so bees will vacate if they are left unbothered.  Be sure to stay back and make sure others do the same, but having an understanding of why bees swarm will allow you to appreciate it while admiring it from a safe distance.


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