swarm of bees in a tree
Swarm cluster

Swarming, in simple terms Mother Nature’s way of making increase, but in reality, a difficult occurrence for both bees and beekeepers, often both swarmed hive and swarm fail during the first winter, and the keeper’s honey crop disappears. In the author’s opinion swarming is caused by poor beekeeping and should be discouraged wherever possible.
There are three main reasons for a hive to swarm, in the normal course of events a cared for hive will not swarm without strong provocation.Congestion, too many bees for the hive space, leading to no cells for the queen to lay into.

An overheated hive will need to reduce the volume of bees, this can often be signalled by a bee beard hanging over the hive entrance, these are usually field bees pushed out by the house bees in an attempt to reduce the hive temperature. Lack of ventilation

An old queen.
It has been noted that an older queen’s pheromone production reduces with age, the bees sense a lack of queen pheromone in their food exchange and the swarming impulse is triggered.

Using a cardboard box for swarm catching.
Catching a swarm

The sequence of events leading to a swarm is very predictable. First, the hive makes what I often think is a momentous decision, to pack up and leave what has possibly been a good home. A number of queen cells are started, these look like a peanut husk, usually at the bottom of the frames between the first and second box, plus one or two in the centre of the frames. Once these are started the bees will begin reducing the egg-laying of the queen, by reducing the amount of food fed to her. This has the effect of slimming her down ready for flight, which causes problems for beekeepers when it is necessary to find her, as she will be not much bigger than a regular bee, just a different colour.

While this is happening all brood will be sealed off, the cells sealed, and on the first nice day after that the swarm issues. This is quite an incredible sight, thousands upon thousands of bees take to the air, the noise is quite frightening and after some milling around, away they go. Often to a tree quite close to the hive they issued from as the queen has to get used to flying, sometimes they’ll return to the hive and wait for another day. If they do land on an accessible branch then that’s the perfect time to re-hive them in a hive or even a cardboard box!

Taking a swarm can be a disappointment, the main problem is failing to get the queen into the box. Having shaken, scooped up, or even picked up in handfuls, bees dumped into a box will leave again, blink, turn around and they’re back in the tree. This can only be because the queen was not taken, the bees know quickly and then go looking for her.
As an aside, it is acceptable to handle bees by the handful when trying to box them, their honey sacs are so full it becomes impossible for them to bend their tails to sting.

Be cautious with a swarm which has issued days earlier, they can be empty having used up their stores and can be angry. Now you know where the stores went from the hive left behind.

I remember the first swarm I took at age 12 on my paper route one spring morning. I dashed home for a cardboard box, without a smoker, veil or any protection, shook them into the box, tucked them under my arm and rode home on my bike. Dangerous to say the least, having grown up I now realise how foolhardy I was!!! The interesting point was to watch them march into the hive I had provided, a fabulous sight which should be experienced by all beekeepers sometime in their beekeeping career. Put down a white sheet in front of the hive and dump the bees on to it, now they get the smell and away they go if you’re observant you can see the queen go in.

We have a standard practice during our swarming season of checking hives every 10 days, a simple check involves a quick inspection for eggs. The hive front is gently smoked, the roof and inner cover removed and more smoke across the top bars and a cover cloth placed over the box top. In the early season the brood will often be in the top box, so a quick inspection starting at the front of the box should reveal an egg pattern. Later in the season, it might be necessary to check the lower box. Once eggs are found the inspection can be finished as it will be at least 10 more days before ‘sealed’ cells will be found.

Running a swarm into a hive.
Swarm Run in.

Horror upon horror, no eggs and queen cells are found!
Am I going to lose the hive?

A great deal depends on what stage the swarm hive has got to. If the cells are not sealed then the urgency is removed. Should the cells be sealed then fairly swift action needs to be taken as they won’t be long before they leave. Nothing is achieved by cutting out cells in the hope they’ll change their minds! It just doesn’t happen. The bees are looking for help, they need either more brood space, fewer bees or more ventilation. You as the beekeeper have to decide which, and then give it to them. This is the perfect time to make increase, in others words a split. Take away all the cells and the frames they’re on, plus a good number of bees, and often the bees will feed the queen to get her into laying condition again, and swarming is forgotten. There is really no need to move the hive a long way away, as a shaken swarm will stay where they are put and not return to the main hive.

Assuming that nothing is done and the hive does swarm, the keeper is not around to take the main swarm, so lots of bees are lost.

What happens to the hive?
Well, all the honey crop has left with the swarm, the hive is greatly reduced in size, in fact opening a hive which has swarmed is quite depressing. There will be very few bees, practically no flight bees at the entrance, lots of sealed brood and a number of cells. The first cell to emerge generally kills all other cells. The virgin stings her unborn rivals through the cell side and the bees then remove the dead occupant. A good point to note, all emerged cells are open at the end, destroyed cells are open through the side. Sometimes the bees will keep the virgins in their cells, in which case after-swarms will issue, even days after the main event. The ideal action check the hive after the swarm has gone and reduce the cells to two or three, no more or the hive will continue to swarm weakening it even more.

The timing of the hive’s return to normal?
Assuming that the virgin emerges safely, it will take approximately 3-4 days before she goes out to mate, hopefully, she’ll return to the hive and set up shop, roughly 4-5 days later she’ll start laying eggs. Then, of course, it will take a great deal of time to build the hive back to its former glory, and often no honey crop as the hive will be too small in its first year.

In the opening statement of this page, I stated that swarming was a difficult occurrence for both bees and keeper, so I hope this has explained why.
I would also like to ask the question:  Don’t you think that a new queen every two years and more hive inspections would save a great deal of grief and trouble?