Why Bees Swarm: Basic Information About Beekeeping

Honey is delicious, and beekeeping can be a fun and exciting hobby, but have you ever wondered why bees swarm? Are swarms of bees dangerous and deadly, or are they simply a part of bee life that we don’t understand? Never fear! Whether you are early in your beekeeping journey or are just looking to learn a little bit more about the fantastic world of bees, keep reading! We will answer some common questions like why bees swarm, is there really anything to be afraid of, and what you can best provide for your swarming and non-swarming bee populations.

If you have been working with bees for a long time, you are familiar with the basic language of beekeeping. However, some quick definitions will keep you get in the know as you learn why bees swarm, what they are actually doing when they are swarming, and how you can keep you and your bees safe during a swarm:

  • Afterswarm – A swarm of bees led by a new queen (This doesn’t happen often, but when it does, a second swarm follows the first.)
  • Attendants – Worker bees that care directly for the queen
  • Brood – Larvae or eggs
  • Cell – Hexagon part of honeycomb
  • Cell cup – Thick bottom part of a cell specifically for a queen egg
  • Colony – Collection of bees that live together
  • Drone – Male worker bee
  • Hive – Bee colony home
  • Queen – Developed female who lays the colony’s eggs
  • Scouts – Bees that look for food or a new home away from the hive
  • Swarm – Group of flying bees
  • Worker bee – Infertile female bees who do the work of the colony

A swarm is a flying group of bees. A bee swarm can often look intimidating, like a cloud of bees heading for an unknown target. Often, swarms of bees scare people off because the bees look (and sound) like they are attacking. But. bee swarms are much less terrifying than they seem! The real reasons why bees swarm are not scary. There are two primary swarm-causing situations in the beehive, and neither of them is a cause for concern.

Why Bees Swarm: Lack Of Space

The most basic reason as to why bees swarm is because the colony is running out of space. While this can happen in the wild, it more frequently happens in manmade beehives. A group of bees breaks off from the hive and leaves to find another home. Usually, about half of the bees in the hive leave, creating two new hives of about half the size of the original one.

When bees decide that they need to swarm and leave the hive, they will start by creating a queen cup, which creates a new queen bee. The old queen will live in the swarm with about half of the bee colony, leaving the new queen to reproduce for the old colony that has decreased in size. Once the new queen hatches, she will be the only queen until the colony decides it needs to swarm, and the process will begin again.

Why Bees Swarm: Reproduction

The other answer to why bees swarm is that they decide as a group it is time to add new bees. Although space is usually the first reason for a beehive to swarm, if bees collectively realize that it is time to reproduce, the only way they can multiply their numbers is to swarm.

It is only through the swarming process that a new queen bee is born; a second queen can only be introduced by being given control of the hive. Two queens cannot stay in one hive, so even if the bees have plenty of space, they will need to swarm and find a second hive in order to create a larger bee population.

When Do Bee Swarms Happen?

Bee swarms start when there is not enough space in the hive for all the bees. This can be caused by too many bees, but it can also be caused by a healthy abundance of honey and brood (larvae) in the hive. This takes up space within the hive, so it may cause bees to swarm in order to find a new hive and add to their population without overflowing their hive walls. This usually occurs during the spring or early summer.

What Does A Bee Swarm Look Like?

A bee swarm that is on the move will probably look like a flying soccer ball. The bees on the outer layer will be moving around and protecting the bees flying on the inside of the ball shape. When they stop to rest, before moving to their new home, they might hang from a branch or in a bush. There will be a number of bees flying around the tight, large cluster of bees. These are the scouts, looking out for a new home base.

When the bees, with their hive mind, determine that it is time to swarm, the first step is to create a queen cup. The worker bees in the colony create the spaces for the queen to lay her eggs (also known as cells). They usually are given a pheromone by the attendant worker bees that keep them from creating cells that tell the queen to lay female eggs (queens can control the sex of the eggs). So, when it is time to swarm, the worker bees create a cell telling the queen that it is time to lay a female egg in a queen cell; this will become the new queen.

Next, the queen will stop eating regularly. She will need to be able to fly a long distance to get to her new hive home, and because she is generally laying eggs frequently, she has been too heavy to fly very far. This process ends when the queen and about half of the bees in the hive leave.

What Happens After Half The Bees Leave The Hive?

This is the first part of the bee swarm and the reason why bees swarm: to leave the hive. After the queen has lost some weight and is able to fly, thousands and thousands of bees will leave the hive all at once. This incredible scene often causes panic in people who are lucky enough to witness it, but unless your home is a likely beehive, you have nothing to be afraid of.

The bees will settle in a temporary location, usually not far from the hive, while scout bees go off on their own to search for a suitable hive location. When they return, the bees communicate and decide which scout’s location will provide the best home for their new and future colony. Eventually, they will choose a new hive home and travel together to start their lives in a new location.

What Happens To The Old Beehive?

Back at the initial beehive, the new queen hatches. The former queen likely laid a number of queen eggs just in case, but there can only be one queen. This means that the first queen egg to hatch destroys all the other potential queens while they are still in their cells, preventing them from ever hatching. After she is done, she is the official queen, and her work of repopulating the hive begins.

Although bee swarms are generally not dangerous to people, there are steps you can take if you think a bee swarm is happening in your beehive or near your home.

What Should You Do If You Think You See A Bee Swarm?

Luckily, bee swarms are good things for beekeepers! If you do not keep bees yourself, contact a local beekeeper (check local listings online) to see if they want to catch the swarm and move them to one of their empty beehives.

Before you approach the bee swarm or contact anyone to remove it, verify the type of swarm you are dealing with. Wasp nests are much different than bee swarms, and you may want to contact your local pest control office or department for their recommendations.

Bees are often not aggressive towards people when they are swarming because they have just lost half of their hive! They also have a significant lack of backup if they were to get hurt or killed. Remember, the queen hasn’t been laying eggs for a while to prepare her to leave the hive, and the new queen isn’t laying eggs yet. However, they may attack if they think that you are trying to harm their colony, so take care when approaching or bothering a bee swarm.

What Should Beekeepers Do If They See Signs Of A Swarm?

An experienced beekeeper can remove the swarm and take the bees to a new hive location. This will usually be done when the scout bees have returned to the group for the night. If you suspect your bees are preparing to swarm (collecting more honey than usual, for example), start preparing a new hive that they can choose as their new home.


Bees are phenomenal creatures, and the reasons why bees swarm are not that different from the reasons people change homes: they want more space! If you suspect you have a swarm in your hive or in your area, contact local beekeepers. They may have just the place for this newly formed colony.

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