DENVER -- Denver resident Mike Russo is busying repaying a debt to an adopted kitten.

Russo credits the cat for helping his wife overcome a serious illness back in the 1970's.

He says, before the cat came along, countless doctors and medications failed to help his wife. Today, his wife is healthy.

Russo made a promise back then to help stray cats. He volunteers for the Feline Fix Clinic.

"It is a spay and neuter clinic for cats," said Amy Angelilli, Executive Director of the Rocky Mountain Alley Cat Alliance.

The clinic is run by the Rocky Mountain Alley Cat Alliance.

It is the place volunteers, like Russo, bring feral and stray cats.

The patients are too wild to adopt, and with some 30,000 cats put down each year in Colorado, this clinic is trying to humanly manage the cat population.

"We can do up to 8,000 surgeries a year with this model. We just need cats. We need people bringing cats in," said Angelilli.

Russo takes time does every week to trap feral cats.

"You get the biggest thrill out of trying to get this tiny creature into this trap, a human trap by the way, nothing to hurt the cat," said Russo.

He traps cats near his home, brings them to the Feline Fix Clinic to be spay or neutered, and then returns them to the wild where they can die off naturally.

"He (Mike) is a really great example of someone in the field who is doing what needs to be done," said Angelilli.

Russo has done this for 12 years.

It is his way of returning a favor to kitten that, he believes, helped save is ailing wife.

"I just get a great joy because these poor little creatures they starve, they freeze, they thirst to death," said Russo.

To contact the Feline Fix Clinic, visit www.rmaca.org