By Anita Oh

MIDDLETOWN, Pa. (CBS) — As sure as the sound of the birds at Core Creek Park, those who regularly visit say you could expect to see colonies of hundreds of feral cats.

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“There’s no reason for it. It’s not a shelter,” said Charles Kissinger. He added that he’s been coming to the park for 20 years and warned management early on about the growing problem of cat dumping.

“I went in about two and a half years ago to tell them to get it it under control or it was going to get out of control,” Kissinger said.

What developed was a pungent smell and areas littered with more than 250 shoddy shelters built by passersby.

“Everything from toolboxes to trash cans to insulated Rubbermaid bins. Most of them were very dirty. A lot of them were broken,” said Denise Bash of Animal Lifeline. It was time for intervention Bash said.

Animal Lifeline is one of several organizations pitching in. Others involved include the Pennsylvania SPCA, Cat Tales, Rescue Purrfect, The Bridge Clinic, Red Rover and Alley Cat Allies. The efforts cost about $30,000, much of which was offset by donations.

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“Everybody had enough,” Bash said. “It wasn’t fair what was happening to the animals here, either the wildlife or the cats. Something needed to be done.”

Over the last two weeks, volunteers installed dozens of insulated shelters, built by prison inmates and pulled nearly 500 cats living in the park. “Everybody is spayed, neutered, vaccinated. They even got flea and tick. Everybody also has a micro-chip,” Bash said.

So far, many of the rescued cats have been adopted, but about 160 cats, deemed non-adoptable, were released back into the park.

“Most of these feral cats will die off within 5-10 years,” Bash said. “That’s our goal, to get it down to zero cats. It’s home to wildlife. It’s not supposed to be home to feral cats.”

Organizations continue to monitor the cats closely. The cats that have been returned to the park are now under a strict four-hour feeding program and the park has put up security cameras to catch anyone who may be dumping their pets.

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Anyone interested in adopting kittens or cats should contact Rescue Purrfect at 267-221-7109 or email adoptions@rescuepurrfect.org. You can also contact Cat Tales at 215-933-6900.