When UC Davis' venerable Haring Barn was demolished over the winter to make way for a new science laboratory building, the veterinary school's Equine Performance Lab moved its operations to temporary quarters on its way to a facility in a new, state-of-the-art building.

Mexican free-tailed bats that had roosted behind barn doors were transported by researchers to another colony in the arboretum.

And rats that had nested in and around the 50-year-old barn, scurried across the street and over to the Medical Surge Complex, finding it especially homey in Surge II's shrubs and insulation.

"They tore down the barn, and the rats went to the next building," said Dave Mattos, custodial supervisor in charge of campus pest control.

During the next few months, Surge II's new occupants made their presence known, creating hassles and headaches for Mediaworks employees there as well as maintenance workers. Some Mediaworks employees saw rat scat drop in front of them, and others complained of respiratory problems.

"It wasn't fun," said Mediaworks business manager Gilda Garcia.

No new infestations were found, but most of the office was closed for a week earlier this month to allow workers to install new ceiling tile and insulation.

Though the infestation around Surge II was relatively severe, rats have become a problem in and around UC Davis buildings over the years, Mattos said. He suspects there were rats in Surge II - which was originally built as a storage area - even before Haring Barn was torn down. More rodents scurry underneath the arboretum's bridges and through warehouse and waste disposal areas.

UC Davis' lush landscaping and large eateries like the Silo and Coffeehouse make the campus "a luxury hotel for rats," Mattos said.

"Rats are (common) to the area," he said, adding that inadvertently "the university does a very good job of feeding them."

When rat problems are left unchecked, they can pose health hazards to both man and beast, said Phil Tillman, a veterinarian with UC Davis' Environmental Health and Safety. Rats can disturb the nests of ducks and valley quail, eating their eggs and young. The rodents also are vectors of at least 20 human diseases, such as typhus.

"We don't have those diseases very commonly now precisely because we do our best to eliminate rats," Tillman said.

Although there could be a connection, he and EH&S director Carl Foreman are unsure whether the rats in Surge II caused the Mediaworks employees' health problems, based on current findings.

"If people have an upper respiratory illness, the first things people think about is an indoor air quality issue such as a rodent infestation," he said. "Rodent dander can (degrade air quality), but you need a lot of particles in the air to initiate a reaction."

Keeping the rat population down on campus is a team effort. Grounds workers cut back vegetation and trees growing too close to buildings, preventing the rats from climbing onto roofs and into attics.

When rats were discovered in Surge II, lead carpenter Irene Hernandez and her crew from Facility Services installed new ceiling tiles, replaced the old insulation and patched up holes in the fire-wall system.

The university's contractor, Ecolab, has a plan for baiting and trapping rats, but rat complaints still seemed to have increased, Mattos said. This year calls for rat control are up about 10 percent over last year. In the springtime - an active season for pests - he gets about three to four reports a week.

"I'm going to write the next contract (which begins in June) to be preventative," Mattos said. "I want the pest control specialists to go out and look for the problems instead of waiting for the problems to occur."

Education is also part of the solution. Mattos tells employees who find rats not to leave food or plant materials out in their work areas or clutter storage areas.

"They don't like being out in the open," Mattos said. "They like finding places to hide."

Mediaworks' Garcia says her employees are making a special effort not to leave food out in their work areas. Other than that, life in Mediaworks is back to normal.

Except, she said, "It feels a lot cleaner."