bees swarming on tree branch

Why Do Bees Swarm? Breaking Point And Beyond

Swarms of bees have been seen all across the United Kingdom. This leads us to the question ‘Why Do Bees Swarm?’. First, we need to shortly address that it is only the honeybee that swarms in the UK.

The short answer to why do bees swarm?

When a honeybee hive population reaches breaking point it will begin to swarm. The queen and half of the bees within the hive will leave to find a suitable location for a new hive. The remaining honeybees will set about producing a new queen, once the new queen has matured she will take her place as the new matriarch.

the triggers

There are numbers of reasons why a hive will start to swarm and the answer to ‘why do bees swarm?’ is for a number of reasons.

Outgrown the hive

In most cases, a hive will swarm because there are too many honeybees for the size of the hive. This is common with managed bees as the frames become packed with honey and larvae.

Other factors

Sometimes hives will fall prey to disease, parasites or a lack of food and water which can lead to a forced exodus. In these cases, the worker bees and the queen will make no preparations for a successor or the continued existence of the current hive. All the bees capable of taking flight will abscond in one large swarm in hopes of finding a suitable location for a new hive.


Honeybees vary considerably in their temperaments and in there swarming habits. However, all honeybee colonies act on a level higher than the individual bee. This ‘hive mind’ of sorts will be motivated to reproduce and continue the survival of the species. This means that some hives will split despite ample space left remaining. This will then allow two queens in separate hives to both continue to produce a brood. Effectively doubling the rate of reproduction.

The start of the swarm

The answer to why do bees swarm is not an easy one. When overpopulation induces an exodus to find a new home the flight is not instant. Careful prior planning and strict execution are required to transplant half a hives population. Normally occurring in Spring the bees will begin with putting the queen on a diet. Due to their size, queen bees are not the best flyers and require rests along the way, any excess weight that can be shed before the flight will make the swarm’s journey safer and shorter. Most queens are required to fly over 250m to find a new location for the hive.

Within the hive, workers will regularly construct queen cups to harbour new queen larvae. Under normal circumstances, queens will not lay eggs into the queen cups and will continue to produce drone and worker bees. When the swarm event is imminent she will lay eggs that will be fed a diet of exclusively ‘Royal Jelly’.

These larvae will then mature into queens. When the first queen hatches she will set about ensuring she is the only surviving successor and taking her place on the empty throne. This process is aided by the worker bees who will remove the wax capping to allow the queen to secure her reign.

During this period of preparation, the bees who are departing will gorge on honey. Using glands in their abdomen honeybees can produce wax which oozes from their pores and forms flakes. The bees will then chew these flakes to create a putty they can make honeycomb structures with. This will be essential when establishing their new hive.

The heart of the swarm

The honeybee queen will leave with half the hive taking to the skies in search of a new home. The exiting half of the colony is called the ‘Prime Swarm’. At first, the swarm will complete a small journey. In some cases, this may just be a trip to a neighbouring tree.

At this stage, scout bees will be deployed to search out potential sites for the new hive. Interestingly upon the scouts return they are judged on the level of energy in their dancing to determine which scouts location will be an appropriate site for their new home. While they await the scouts return the remaining bees in the swarm will protect the queen from any potential predators or harm. The queen will still struggle in the upcoming flight despite her recent dieting and the swarm may have to stop at regular intervals for her to recover.

why do bees swarm

the location of the hive

The scouts sent from the hive don’t have an easy task ahead. They need to try and find a suitable bit of real estate for the swarm. The location will need to be sheltered from the elements but will still require some sunlight for warmth. It will require a small protected entrance and no other unwanted inhabitants within. When all of these criteria are met or at least partially met the scout bee will return to the swarm to report her findings.

Upon returning the scout bee will begin a fascinating course of action. Each scout will perform a ‘Waggle Dance’ after returning from a potential new site. The vigour and energy portrayed in this dance will communicate it’s a potential success, direction and distance. If this dance is performed with particular vigour and energy other scouts will be persuaded to inspect the location.

This process continues for up to three days with a gradual winner emerging. When one site gets approximately 80% of the scout bees approval the decision is made. After the democratic process has been completed the whole swarm will take flight. Scout bees will fly above the swarm in the required direction to guide it towards the sanctuary.

Human interaction with swarms

Considering the population of both ourselves and the honeybee instances of human swarm interaction are relatively low. Sightings are often higher in hotter springs/ summer with an increase in urban sightings. This may be due in part to the marked increase in beekeepers nationally. Nowhere else has this change been as pronounced as urban areas. Beekeeping has seen a huge uptake in towns and cities as awareness around the plight of bees spreads.

Whilst this is, on the whole, a positive it has meant that cases of overpopulation in managed hives have been increasing and therefore interaction with humans in their environment.

On the whole, honeybees are generally fairly docile during their swarming period. Despite its somewhat threatening look a swarm is gorged on honey and remains in a fairly docile state. The swarm will only act if intimidated or if the queen is threatened.

If you come across a swarm in an urban environment where they are a threat to themselves or other people your best course of action is to contact a local beekeeper in the hope they have a vacant hive that they can be transported to. You can use the British Bee Keeping Associations handy little tool to locate a beekeeper close by.

Check out our article Everything You Need To Know About Our Friend The Honey Bee

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