EVANSTON, Ill. — In a bid to solve what appeared to be an intractable rat infestation, residents at an Evanston apartment complex invited a pair of feral felines onto their property.

Now, they say the cats have transformed their courtyard and gardens from a moonscape of rat burrows to a nearly rodent-free pasture.

Sherman Gardens is the only Evanston property with a feral cat colony provided by Tree House Humane Society, a no-kill shelter with a trap, neuter and release program for feral cats. The organization sponsors 150 colonies comprised of more than 400 spayed and neutered feral cats, according to its website.

Sherman Gardens’ feral felines, known as Stinky and Sweetie to most residents, have called the courtyard of the 132-unit apartment complex home since late May of this year, said Diane Petersmarck, a trustee for the apartment cooperative and one of the lead caretakers of the cats. The cats are micro-chipped, tagged and fed twice daily by a group of roughly 10 volunteers, Petersmarck said. They sleep inside storage buckets filled with straw inside a large cage hidden from view by a few shrubs and tucked away between a fence and one side of an apartment building. In colder months, their shelter will include electric heating pads and heated water bowls, in addition to added insulation on the exterior of the cage, she said.

Before the cats arrived, Petersmarck and several other Sherman Gardens residents said the apartment complex was plagued by rats. They tried bait traps, an ultrasound machine designed to emit a noise bothersome to rats and filling up the many burrows littering their courtyard with used cat litter.

The cat litter “worked better than anything else we tried, but it was a lot of work,” Petersmarck said.

Sherman Gardens resident Michael Stephens said he remembers watching movies on the patio and seeing rats scurry to and fro out of the corner of his eye. With the cats now patrolling the property, he said he doesn’t see that anymore and the burrows that were once ubiquitous are now rare.

“Nobody’s worried about a rat running across their feet on the patio anymore,” said Sherman Gardens resident Barbara Pearson.