Swarming in Honey Bees

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Swarming in honey bees is a natural behavior that allows them to create new colonies. During this mysterious and exciting event, approximately half of the colony population pulls up roots and flies to a new home. Doesn’t this seem like a risky move? I think so. But, honey bees have been using this survival technique for millions of years. Join me-as I take you on a short journey into the world of the bee swarm.

Large swarm of honey bees hanging in a tree.

Being a beekeeper, I get a chance to observe different colonies. Over the years, this first-hand experience has helped me recognize many honey bee characteristics that every colony shares. They are different and yet alike.

What is a Swarm of Bees?

A bee swarm occurs when a group of bees leaves the mother hive to make a new home in a different location. This happens to wild bee colonies living in hollow trees and it happens to those living in modern beehives too.

As thousands of bees fly through the air – in a seemingly erratic pattern – you will hear a loud hum! A bee swarm in the air looks like a swirling mass of bees flying in circles.

They are so impressive – you will never forget the first one that you see. In fact, the sight can be frightening to those who are not familiar with the behavior.

You may also see a honey bee swarm hanging from a tree limb, or gathered on a fence, chair etc. This is a transition location – where the swarm is resting on its journey to a new home.

Swarm of bees flying over homes in city.

Why Swarming Behavior Occurs in Bees

Swarming is reproduction on the colony level. The goal is to produce more colonies of bees. This is accomplished by growing a large population in the hive. The colony then splits itself into two groups.

The mass of bees in the swarm represents about half of the colony population. However, swarms can be very large or very small.

Upon arriving at their newly selected home, the swarm will begin to build comb and established itself as a new colony. Back at the mother hive, the remaining population will get busy caring for a new queen and rebuilding the population.

The Swarming Process: How it Begins

Though it may seem to be so, swarms don’t just happen. The colony begins preparations weeks before the event.

  • scouting
  • preparing the queen
  • queen cells
  • leaving the hive – blast off
  • transition spots
  • leaving for new home
Worker bee inspecting possible new home for a bee swarm.

Scouts Search For Sites

At any given time, a percentage of workers serve as scout bees. Their everyday job is finding food sources for the colony – nectar and pollen. But, they also seeking out possible nesting sites for future new homes.

Preparing the Queen to Fly

When a prime swarm (the first of the season) leaves a hive, the mature queen normally goes with them. Truth is – a well developed laying queen is too large to fly – she must be slimmed down.

As the time to leave approaches, worker bees feed her less so she can slim down and get that big booty off the ground. Her egg laying will also slow down right before leaving.

Queen Cells are Prepared

If the old queen is leaving with the swarm, the mother colony needs a replacement. An interesting fact about the queen bee – she is needed to get a replacement underway.

Once a firm decision has been made to swarm, workers prepare cells where the queen lays fertilized eggs. Now, these are called “queen cells“.

Larger than regular brood cells, peanut shaped queen cells hold the future queen for the mother hive. Several queen cells are constructed with developing queens in each. Only one will ultimately survive.

Worker bee tending swarm queen cells in hive.

Leaving the Hive

Several terms are used in beekeeping to describe the actual event when the swarm leaves. A hive “casts a swarm”, “throws a swarm”, “a swarm issues from” – you pick, they all mean the same thing – the bees are leaving!

One mystery of honey bee swarming is – what is that final trigger than makes things happen? Why today and not tomorrow. The bees know – but they are not telling.

On a warm day usually between 10 A.M. and 2 P.M. the hive becomes very active. A strange roar can be heard inside. Workers run around inside the hive in a frenzy.

They chase the queen and keep her moving until she is willing to leave the hive. Thousands of bees pour out of the hive entrance and fill the area. At first, they fly around and around high up in the air.

Honey bee swarm clustered on arbor.

Temporary Transition Spots

In most cases, a bee swarm will sit down somewhere near the hive. It is often a nearby tree, bush or other natural structure chosen for the temporary stop. But, sometimes their choice can be very surprising such as a mail box, a fence or a car!

If you are involved in urban beekeeping you must be extra vigilant about swarm control. People unaccustomed to honeybees tend to get excited over this.

The cluster of hanging bees remains in this temporary resting place for a brief time. Perhaps, a couple of hours or even overnight-rarely more than a couple of days.

During this time scouts to and fro from the hanging swarm to possible new locations. They return to the cluster and perform bee dances on the outside – trying to recruit others to vote for the location they have found.

When honey bees are in this transition spot, it is common for beekeepers to take advantage of the opportunity to capture the swarm.

Taking Off to Their New Home

When most of the scouts come to a consensus or agreement – it will be time to go. Seemingly like magic, the entire ball of bees will explode into flight and off they go towards their new home.

On occasion, a swarm will get stuck and fail to move on. In this case, it is good to contact a local beekeeping association and see if a beekeeper will help. Most colonies do not survive the winter on exposed honey comb.

The Swarm Season

When are you most likely to see bee swarms? They can occur at any time during the warm season but Spring is the most likely time.

This is when the best flowers for honey bees that provide food are in full swing. The bees see this as a signal to increase brood production-and they do. As the population grows, the interior of the hive becomes crowded. It’s swarm season!

Keep in mind, it is not unusual to find swarming colonies during Summer or even Fall. It is often difficult for the beekeeper to understand why hives swarm in Fall. Many late season swarms fail.

Risks for the Colonies

Sometimes, swarming seems like a risky move. The mother colony is faced with the need to get a new queen mated. The mating process of honey bee reproduction has risks.

If the candidate is eating by a bird on her mating flight – the original hive may be left without a queen and it will fail.

The new swarm colony is at risk of not being ready for Winter – or being overtaken by stronger colonies or predators. But, nature has a pattern that has worked for millions of years – even when we don’t understand it.

Why Beekeepers Strive to Prevent Them

As a beekeeper, I love seeing a wild swarm – or any swarm actually – as long as, they come out of someone else’s hive.

We have already talked about some of the risks involved for the bees. And, a colony that swarms will usually produce less honey that season.

You will hear of numerous methods for preventing swarms in honey bees. Many beekeeping books are full of tactics that work some of the time. None of them work all the time.

We commonly watch for the first signs of queen cell development or even bees backfilling the brood nest – both occur before swarming.

Small bee swarm moving into a bait hive or swarm trap box image.

Preparing for the Season

Because swarming is a natural thing, sometimes you just have to roll with it. Spend some time setting up a swarm trap. If successful, at least you are preventing them from getting away completely.

Beekeepers employ different methods of to attract swarms to traps. Don’t be afraid to make adjustments to your honey bee swarm trap or location.

Don’t be overly focused on what the books say. You never can tell what bees will do. If you are lucky, bees will eventually move in!

Learning how to catch a honey bee swarm in a tree is easier but you can’t count on finding them in the transition phase. Traps work when you are not at home.

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Is honey bee swarming the same as migration?

No, a bee swarm is not evidence of migration. In a swarm event, roughly half of the population stays in the original beehive. There is no back and forth traveling between the old home and the new one.

Are bee swarms dangerous?

No, in general honey bee swarms are very docile and pose no danger to the public. Leave them alone and they will often be gone the next day.

What should you do If you see a swarm of bees?

In most cases the swarm will move on in a few hours or the next day. If not, call a local agricultural office or local beekeeping club – someone would love to come collect them.

Will Bees Swarm Without a Queen?

Basically, no. A swarm would serve no purpose with having a queen bee. However, the swarm may contain a virgin queen who has not mated yet.

Will a swarm of honey bees sting you?

Yes, they can and will-if you bother them. Why do honey bees sting? They only sting for defense. Keep children and pets away until the bees move on.

If I find my beehive empty, does that mean the bees swarmed?

Not necessarily. Finding a previously occupied beehive empty, is not signs of a swarm. When all members of the colony leave, this is called absconding bees.

Absconding is most often the result of disease, pests or too much beekeeper interference. However, failure to monitor your hive could result in an empty hive if the mother colony failed to requeen itself and died out.

What to do if a Swarm of Bees Attacks You?

People living in regions with Africanized honey bees must be extra careful. They have a severe response to threat.

If you are ever in a situation where a swarm of honey bees decides you need to go – go. Walk away quickly and get to an interior space – inside a house or even in a car. It is better to be in the car with 10 bees than outside with 10,000.

Final Thoughts

Bee swarm are exciting. I remember my biggest swarm catch like it was yesterday. Perhaps we beekeepers spend too much time trying to prevent swarms. It is a vital part of bee survival.

Our best hope is to work with the natural tendencies of the colony. And, take a moment to appreciate the majesty of the process. May your bee swarm season be a blessing.

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