Swarm of honeybees in a birch tree.

Why do honeybees swarm in spring?

Swarm on tree branch in residential yard.

Hi, This is Adriana, the beekeeper from South Mountain Bees.

This is the time of year when people start seeing bucketloads of bees hanging from trees, street signs, and even car windshields. So I thought this would be a good time to talk about swarms and try to answer the question:

Why do honeybees swarm in spring? 

In late winter, when it is still cold out, and there’s even snow on the ground, the bees keep the hive nice and toasty for the queen to be able to start laying eggs, and to keep the eggs warm enough to survive.

At a thousand or more eggs a day, the population of the hive builds up pretty quickly.

It only takes three weeks for a bee egg to become an adult bee. As the bees hatch by the thousands on a daily basis, it starts to feel pretty crowded in the royal palace, and it's time for some of them to find a new home. Many bees get together with the queen and leave looking for a new home, and that's the swarm.

To be able to fly, the queen bee has to slim down and stop laying eggs. But before they leave, the bees need to make a new queen, otherwise, the bees left behind will be queenless, and without a queen the colony is doomed. Without a queen there will be no eggs, so once those bees die, it will be the end of the colony. 

Therefore, for some of the bees to be able to leave, there has to be two queens, the old queen and the heir to the throne still wrapped in its cocoon ready to hatch.

Queen cell in a honeycomb frame.

For that reason, before the queen stops laying eggs to swarm away, the bees need to set aside a few eggs to make a few queens to leave behind.

They only really need one, but nature has plenty of built in redundancy to make sure operation swarm succeeds.

It takes nine days for the bees to finish taking care of the the future queen (or queens) and seal the queen cell. At the end of that process is when the bees swarm: when the queen cells are sealed. The new queen hatches from a cocoon that looks like a peanut shell (see the picture). The old queen leaves with most of the colony. They say  up to 75% of bees leave with the old queen in the search for a new home.

That's why it is essential for beekeepers to try to control swarms. Losing 75% of the bees just before the peak of the nectar flow means that there won't be much honey in that hive by the end of the season. 

What should you do if you see a swarm?

Swarms can look pretty scary. There can be tens of thousands of bees in a spring swarm. But don't worry, their goal is not to go after humans, but to find a new home. They are just making a stop while they decide on their final destination.

Call a beekeeper. Every beekeeping club keeps a list of beekeepers who will collect the swarm, and they will give them a new home. You can contact us at info@southmountainbees.com, or message us on IG @southmountainbees.

Last year we caught four swarms all over town. We’ll see what this season brings. 

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