CHICAGO (CBS) — A pair of bicycles parked on the street pole downtown Monday were impervious to theft.

Not because of a high-tech lock, but, rather, a swarm of bees.

The bees gathered by the hundreds near a Divvy bike stop at Michigan and Madison.

The swarm was covering two personal bicycles, locked to a street pole, parked near the Divvy station.

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They likely gathered there from a nearby hive that made a new queen bee, said beekeeper Jana Kinsman, who was called to the scene to move the swarm.

“The old queen takes off with about a third of the population … the old queen lands on some object like a bicycle or a tree branch and the population surrounds her,” Kinsman said. The bees then start to look for a new, permanent home, like a hollowed out tree.

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Around 2:15 p.m., Kinsman arrived to remove the insects from the pole.

It took about 30 minutes to locate the queen bee and transfer the swarm into a portable hive.

“As soon as the queen changes locations, all of the workers follow into the hive,” said Kinsman, founder of Bike A Bee, which offers a variety of bee services, from swarm removal to classes on bee keeping.

After Kinsman finished her work, Sarah Bradley, who rides to work from Humboldt Park, was able to get her bike back.

“I get here around 11 o’clock just to go to work and there was no trace of any bees anywhere,” Bradley said. “Everything seemed fine. This is really strange and bizarre.”