In Chicago, one neighborhood's rat problem is about to get a lot worse.

Crews are preparing to tear down an old hospital and when the wrecking ball starts swinging, the rodents living in and underneath the aging structure will scurry.

The city and the developer are setting poison baits and traps to help control the problem, but some residents are turning to one of the rats' worst enemies instead — cats.

Construction On Old Buildings Worsens Rat Problem

Chicago's upscale Lincoln Park neighborhood is known for its fine bars and restaurants, trendy clothiers and elegant row houses mixed with luxurious town houses and yuppie apartment buildings.

Like many densely populated urban neighborhoods, Lincoln Park also has rats.

A lot of rats. "They totally freak me out," says Courtney Bledsoe, as she sees a rat dart across the street while picking up her son at a Lincoln Park preschool.

"Every night when I walk down the sidewalk, I see rats," says 36-year-old Kelly McGee, who has come to accept this aspect of city living. "It freaks out my sister. She screams when she sees them but they don't bother me so much. It's an urban area; I don't know what else we can expect."

McGee can expect the rat problem to get a lot worse. She lives just down the block from the old Children's Memorial Hospital, which is about to be torn down as part of a massive redevelopment project.

"Construction all over the city often disturbs rodents who are living underground," says Lincoln Park's City Council representative, Alderman Michele Smith. In anticipation of the redevelopment of the century-old hospital, Smith wrote what she says is the most stringent anti-rat development ordinance in the country.

"Before excavation begins and throughout excavation and construction, every developer has to do active rodent abatement on site," Smith says.

Already, there are poison bait boxes all around the old hospital complex, and the city is doing additional rodent abatement in the neighborhood too. But the developer of the hospital site still warned residents in a recent community meeting that when demolition begins later this month, the rat problem could be "awful."

If anyone knows what constitutes an awful rat problem, it's Victoria Thomas.

"At one point we had around 400 rats living next door," says Thomas, who lives a few miles north of Lincoln Park in Chicago's Lake View neighborhood. "It was horrible."

Standing in the unusually big backyard behind her condo building, Thomas says she was completely overrun by rats a few years ago.

"No one used the yard one summer because every time you'd go out, they'd like run across your feet," she says. "Once it got dark, you would hear them, 'tch, tch, tch, tch, tch, tch, tch tch,' back and forth on the deck. ... We'd all lift our feet up because they're underneath the table."

The rats came over from the yard of apartment building next door, where they feasted on restaurant garbage and dog feces. Thomas says she tried everything from trenching and underground fencing to poison traps, but nothing worked. Until she got some cats.

"Oh my God, that one, that's my killer out of the three," says Thomas, pointing to one of her cats as it runs across the backyard. "That one loves to hunt."

The three rescued feral cats were sterilized and vaccinated by the Tree House Humane Society and relocated to be put to work in Thomas' backyard to prey on rats.

From the first day she got the feral cat colony, Thomas says the rats started to disappear.

"These cats are amazing. They cleaned up everything. We have a couple of dead rats, you know, once a month, we'll get a dead rat. [The cats will] leave it here, they'll bring it to my door," she says.

The Cats Don't Just Kill

These aren't cuddly house cats. They stay outside. Thomas provides them with food, water in a heated dish and insulated shelters, while the cats patrol the backyards in her block.

"The cats will kill off a great deal of the initial population of the rats," says Paul Nickerson, who manages the Cats at Work program for the Tree House Humane Society. "But through spreading their pheromones, they will keep other rats from filling their vacuum."

Nickerson says that's what makes the feral cat program so successful in keeping the rats away long term. "Before the cats showed up, there were no predator pheromones in the area," Nickerson says. "Now that cats are here, there's predator pheromones and the rats aren't stupid. They smell the predator pheromones and so they'll stay out of the cats' territory."

After Smith highlighted the program in a recent newsletter, Nickerson and the Tree House Humane Society have been getting lots of calls from people seeking their own cat colonies.

That means a lot more feral cats that might otherwise be euthanized will be cared for while doing something that they love: hunting rats.