t's spring in Tucson. The flowers are blooming, the birds are chirping and the Africanized bees are swarming.

Northwest Side fire officials say there have not been any Africanized bee attacks this year, but they are preparing for an active season.
"We haven't had any calls for bees recently," said Rick Flores of Rural/Metro Fire District. "But we are anticipating the season to start any time now."

When temperatures get warmer, bees don't necessarily get more active, but they do tend to swarm, said Gloria Degrandi-Hoffman, research leader with the Carl Hayden Bee Research Center in Tucson.

"It's warm here most of the time, so they are really active throughout the year," she said of honey bees. "This is the time of year when bees swarm — it's a natural phenomenon."

Colonies build up populations in the early spring so nests become overcrowded, causing the bees to look for other places to live, Degrandi-Hoffman said.