Urban swarms: Why do honeybees swarm?

http://www.bbc.co.uk/news/uk-england-26988041

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There were bee swarms over the weekend - in central London and at a shopping centre car park in Bournemouth - but what causes bee swarms, especially in urban areas?

The sight of thousands of swarming bees heading in your direction, clumped on your car, a window or on top of a post box, can certainly be unnerving.

But these large groups of buzzing golden brown and yellow bees are more focused on finding a new home than attacking anyone.

The British Beekeepers Association (BBKA) said the spell of warm weather had been ideal for honeybee colonies to start swarming.

As the number of bees in a hive grows the colony runs out of space and it is time to split and look for a new home - so they swarm.

Swarm collector David Teasdale, a BBKA trustee, said: "People are becoming more interested in beekeeping, and thank goodness about that, and there tend to be more urban beekeepers.

"There are some naturally occurring colonies around, but not that many, and a lot more people in suburban areas are beekeeping.

"We would encourage that, but they need to go through the colonies and check them for swarm prevention."

After surviving a cool winter, a bee colony can expand up to 50,000 worker bees in the warmer weather, living with a queen bee, which produces a "queen pheromone".

With thousands of bees living together, not all of them receive the queen's pheromone signals - and so create a new queen.

The old queen and flying bees then leave their home to establish a new nest, but with the queen bee not the strongest flyer, they can stop to take a rest.

"All they want is to find a new home," Mr Teasdale said.

"And before leaving they gorge on honey... so generally speaking if they are swarming they are in a semi-docile state."

When honeybee numbers fell to near catastrophic levels interest in their plight rocketed, with increasing numbers keeping "urban bees" at their homes or on the roofs of office blocks.

Alison Benjamin, co-founder of Urban Bees, said: "A few years ago the BBKA only had 10,000 members and now they have 24,000 members and many of those are increasingly in urban areas."

She said it was important people keeping bees considered "managing their colonies" with an artificial swarm.

"In an urban environment it is important we are aware that we are living side by side, people and bees," she said.

"You can split the bees - taking the old queen yourself and put her in a new hive... but you have to be experienced to do that.

"You need to go on a beekeeping course, you need to join a beekeeping association, or maybe be monitored by an experienced bee keeper."

While a swarm's priority is to find a safe place to set up its new colony, people are still urged to act with caution if they see a swarm.

"The public is increasingly aware of the importance of honeybees... but a swarm of bees still can be scary," a BBKA spokeswoman said.

"The public should not be alarmed if they see or come across a swarm of honeybees.

"Contrary to some recent press headlines they are neither angry nor likely to attack... their sole intention is to find a new home to build-up a new colony."

The BBKA has a list of beekeepers willing to collect swarms, but adds that people often mistake groups of other types of bees or wasps - which they do not collect - for honeybees.

"The number of calls for honeybees is about stable, there might be a fractional increase," Mr Teasdale said.

"But what has increased is that whenever anyone sees anything that flies in their garden, they automatically assume it is a swarm of honeybees.

"We had 275 calls in a weekend, which is unbelievable, and a lot of them are to do with bumblebees, or later on in the year, wasps... it is getting out of hand."

He urged members of the public to learn how to spot a honeybee swarm and to check their website for what to do when they see one.