CHICAGO (CBS) — To combat the rat problem in Chicago, one North Side ward is turning to alley cats.

As WBBM Newsradio’s Nancy Harty reports, the Tree House Humane Society offers an alternative to the poison that the city usually puts out to kill rodents.

LISTEN: WBBM Newsradio’s Nancy Harty reports

“Our tax dollars are spent on this poison, and it’s not effective. It’s kind of a Band-Aid,” said Tree House Director of Development Jenny Schlueter.

Schlueter says they began placing neutered, vaccinated and microchipped feral cats in the 47th Ward in April as part of a pilot program.

“It’s not so much the hunting behavior, but just their presence in an area that deters rats from being there,” she said.

Those interested in the “Working Cats Program” should know they will be feeding and providing shelter for at least two cats that would permanently live in their backyards or garages — not in their homes.

A fee of $40 per feline is assessed, and it drops for additional cats.

Schleuter calls it a win-win situation because they’re getting rid of rats without using tax dollars and saving feral cats from the gas chamber, where roughly 11,000 die in Chicago each year.

By some estimates, there are 500,000 feral cats living in the city, and many are difficult to place because they’re not socialized.

Schlueter says they have a 90 percent success rate and hope to expand the program beyond the 47th ward.