Why bees swarm and what you should – and shouldn’t – do when you come across a colony on the move

A huge, chaotic whirl of bees hanging on a branch or piled on the ground may naturally give you cause for alarm.

Spring is the time of year when you’re most likely to come across swarms of honey bees in seemingly random places.

But beekeepers say swarms are nothing to fear and are essential for the future pollination of a third of the food we eat. 

So, let’s find out why bees swarm, and what you should – and shouldn’t – do when you come across a colony on the move.

Why do bees swarm?

Swarming is part of the natural reproductive life cycle of honey bee colonies and usually happens in spring as the weather warms up and flowers start blooming.

Honey bees, Apis mellifera, usually swarm for two reason: when it becomes too crowded in the hive or when they’re pushed out by pests or disease.

Mark Paterson has been keeping bees both in the United States and in Canberra for nearly 20 years, and currently has 26 hives in 10 locations across the capital.

He says, as the numbers build up, the old queen and about half of the hive break away and head off to start a new colony.

“They will usually come out as a cloud of bees and they will form a clump on a tree or a fence within 30 metres of the hive, and they will consolidate on that one spot,” Mr Paterson says.

“Then they’ll be sending out scouts looking in an area of up to 70 square kilometres looking for a new home.”

If you look closely, you may even spot a scout doing the waggle dance to tell the others they’ve found a great new home – usually a tree hollow, possum box or other cavity at least 40 litres in size.

“When the scouts come back, they do a figure-of-eight dance and the orientation of that dance, the direction in relation to the sun, tells them what direction to go,” Mr Paterson says.

“When they shake their tail, the duration of shaking the tail determines how far to go. For every second it’s about 750 metres.

“They’ll do this multiple times to encourage other scouts to go and investigate the space that they’ve identified as a suitable home and more scouts will go out.”

While the scouts are out house hunting, the rest of the bees stay in a protective ball around the queen.

Once the scouts have come to a consensus, the swarm moves on, but the bees may need to rest along the way.

“The new place could be 4 or 6 kilometres away, which is a long way for an insect,” Mr Paterson says.

“So, they may actually identify a space and head in that direction but not make it because the queen gets tired, and she has to stop.

“Then they’ll reconsolidate around her and they might reach the location for the new hive at the end of the day or the following day.”

What should I do if I find a swarm of bees in my backyard?

In most cases, Mr Paterson says, bees are docile while they are swarming, as they have a belly full of honey and “they have nothing to defend”.

However, if their queen has gone (for example, eaten by a bird) they may be agitated.

So, if you see a swarm of bees fly into your yard, keep children and pets away and give the insects space to settle and clump together.

Mr Paterson says the swarm will usually move on in a few days.

But if you’d like the bees gone sooner, or are concerned that they might set up shop around your property, call a beekeeper who specialises in swarm removal.

There are beekeeping associations and societies in each state and territory – for example the ACT Beekeepers Association in Canberra – that provide a list of collectors who will gather a swarm at no charge or for a small fee.

The collected bees will be rehomed as a new colony or, if they’ve lost their queen, incorporated into another hive to strengthen numbers.

Dermot AsIs Sha’Non, who has been beekeeping for more than 12 years and currently has 50 hives, says having a swarm collected will prevent it from establishing a hive in an unwanted location around your home.

He removes both swarms and colonies and says it’s much easier to remove swarming bees than it is an established hive.

“Those scouts will find a permanent location and that permanent location is often a chimney or someone’s walls or a spot that’s much more difficult to get at,” he says.

“So, it’s easy to collect the swarm when they are on a tree than it is to cut open someone’s walls and take out an established colony.”

Mr AsIs Sha’Non says how long a swarm will hang around can also vary, and in some cases, scouts can become a nuisance by buzzing around an opening to your home.

“Scouts may find somewhere within half an hour and they just take off, or they can sit there for a week,” he said. 

“You could have scouts banging around the back door for a week while they’re trying to make their decision.”

What shouldn’t I do with a swarm of bees?

If you find hundreds of bees in a ball in your backyard, don’t try to encourage the swarm to move on.

Spraying the bees with water, smoking the bees or throwing stones at them could anger the insects and encourage them to sting in defence. It will also make it harder for a beekeeper to remove the swarm.

“Also, if they have decided to move on, then you’ve just made it harder for them to fly and you might have half the mob move on, and then another half that’s confused and hanging around and causing trouble,” Mr AsIs Sha’Non says.

And most importantly, the beekeepers say, don’t spray the bees with pesticides. 

“Most of the time they will not be concerned about you; their only concern is to protect the queen,” Mr Paterson says.

“Just leave them be and enjoy the moment.”

Why we need bees

Bees provide essential pollination for a vast range of fruits, vegetables and nuts, and Mr Paterson says we would all notice if bees were to disappear.

“What most people don’t understand is bees are the most important species on this planet for the future of mankind,” Mr Paterson says.

“One-third of what you eat relies on it being pollinated and that’s usually by a bee.

“If there’s no bees, there’s no pollination, if there’s no pollination there’s no fruits and nuts.”

Mr Paterson encourages everyone to do what they can to support bees, from planting flowering plants in their garden to buying locally sourced honey.

“Bees have been on the planet for about 25 million years. If we disappeared, they’d be fine. If they disappear, we’re gone,” he says.

Both Mr Paterson and Mr AsIs Sha’Non are seeing fewer bee swarms around Canberra this year and they are unsure as to why. 

They say it’s not due to varroa mite, because the parasite is yet to make it to the ACT.

But Canberra beekeepers are anxious about the inevitable arrival of varroa mite, and Mr AsIs Sha’Non says people will notice when it starts impacting wild colonies.

“The experience overseas has been that when varroa mite takes over, upwards of 90 to 95 per cent of the wild colonies are destroyed,” he says.

“We won’t notice that until we start to see farmers wondering where the pollination services have gone that they’ve always taken for granted.

“These wild colonies that have been out there doing a fantastic job and it’s been a job in the background that no one’s paid attention to, until they start to see it disappear.”