Halloween came early to tenants of the Valley Bank Tower, 80 W. 300 South, as 30 bats invaded the building's stairwell.

A lawyer first encountered the furry mammals when one flew in his face early Wednesday.Building security officer Norm Moses, armed with a broom, spent most of the morning shooing the creatures from the 12th floor stairwell to the first floor and out the door. "I've heard of sheepherders, but never a bat herder," Moses said.

The bats apparently flew into the stairwell Tuesday night through an open skylight on the roof.

Dr. Lorraine Shabestari, a University of Utah clinical veterinarian, said bats usually are more active this time of year because the insect population is large.

She said it's not unusual for the winged creatures to congregate in large groups. "They're rather social animals," she said. "When they find a desirable place, they'll stay."