More and more people around the Bay Area are having spring encounters with swarming bees, including students at a Vacaville elementary school where a swarm took over a tree Tuesday.

Tens of thousands of bees suddenly swarmed a tree in the schoolyard at Foxboro Elementary School in the afternoon, but the incident seemed to arouse more curiosity than fear.

"It looked as if there was just a big mass of tan bark or something," said Foxboro sixth grader Emily Fernandez. "It was just kind of lopsided. It wasn't round or anything."

The swarm of what beekeepers said was approximately 80,000 bees took the school by surprise, but didn't alarm the students.

"The bees seemed to be very calm and didn't seem to be agitated or attacking or anything," said Foxboro principal Lisa Eckhoff. When asked if it was scary for the kids, Eckhoff replied, "I don't think so. I think it was just a cool learning experience for them."

No one was stung, and beekeepers removed the bees with no problem.

Brian Wort, the president of the Mount Diablo Beekeepers Association, told KTVU his organization is receiving two or three calls a day about swarms.

"They're out looking for a place to land and make a nest," said Wort.

He said swarms such as the one in Vacavalle have become common because hives are splitting as new queens are hatched.

Experts told KTVU when bees are swarming, the bees are not aggressive at all. In fact, swarming bees are much safer to be around.

"When they swarm, they don't have a hive to defend, so they're less aggressive," said Wort. "They're also engorged with honey, because they bring as much of a food supply with them as they can."

Wort, who showed KTVU inside his hives at Forest Home Farms in San Ramon, said the swarms are sizable this year, but that there is no reason to be frightened if you encounter one.

"That's what a swarm is; it's propagation for honey bees," said Wort.

Beekeepers said they'll be happy to come and remove the bees safely. Swarming season lasts through May.