Bates placed a can of cat food, dripping and smelly but presumably attractive to felines, in a metal raccoon trap. She then stepped back and watched what she calls a "feeding location" -- a place where a colony of homeless cats visit each evening for dinner.

Bates estimates that several hundred such colonies are roaming around Oakland. This size of this animal population, though, is being limited -- partly due to the efforts of volunteers like her. In the summer, though, these volunteers need to spend many nights trapping and keeping these felines from reproducing.

"We're at that time of year that we're overwhelmed," the Laurel resident said, pointing to the top of a fence: a white cat watched her from the distance.

Bates captures, neuters (or spays) and releases feral cats -- animals considered the most difficult type of feline. Ferals, which have lived without human contact since birth, tend to distrust people; and few individuals are willing to take the risk of adopting these wild animals. Plus, the felines kill birds, which make them a pariah to bird advocates.

Bates came to the same hills parking lot the night before. She reads. She returns the phone calls from the day that came to Island Cat, the volunteer rescue agency that she and a half dozen others run in Alameda. From West Oakland to San Leandro, Island Cat volunteers set traps.

Summer is her busiest time. This is when kittens, conceived during fall and winter, appear.

A complex problem

She and other volunteers find cats congregate near where Oakland residents leave or throw away food -- from restaurants and gas stations to backyards and gutters. Her organization finds homeless cats, neuters them and works to get them adopted or puts them back where they were found.

Homeless cat colonies, ranging in size from three to several dozen, survive in groups and stay within boundaries hard for humans to specify but obvious for other felines to recognize. They scour neighborhoods for food. They mark doors and gardens with urine. They howl at night.

The cats fall into two categories, Bates explained: feral or stray. While stray cats once lived in homes and grew up around humans, ferals were raised outside, without human contact.

Bates' group works under the philosophy that cat colonies are inevitable; exterminating feral cats won't stop more from coming back, but halting reproduction will.

"(Euthanasia) may temporarily fix the problem, but it's not a permanent fix," she said, near the back of a group of stores she asked not to print, to keep people from abandoning cats in the spot.

Her organization and others are battling the issue on several fronts. On one hand, they are trying to spay or neuter feral cats that annoy neighbors. But that, she said, leaves them with a task too large for a handful of volunteers.

Many residents leave food out for strays that live near their homes. So, Island Cat is also trying to help residents understand how to trap the cats and get them neutered themselves.

"They realize: 'I've been feeding these cats, and now I really have a problem,'" she said.

Neighbors who get involved help manage the cats, she said. And they also help manage the money. Island Cat and other similar organizations pay about $50 to get each cat neutered or spayed by a veterinarian willing to offer reduced prices, Bates said.

Rose Jones, who lives near Joaquin Miller Park, volunteers with Island Cat. Jones let know about the colony in the hills earlier this year. She started capturing cats 10 years ago on her own.

"When I first started, I didn't know how to trap," she said, as Snowbell, a stray cat with long white fur and blue eyes that she's befriended snuggled up to her ankle. Now, the colony started at about 20 has dwindled to less than 10, according to Bates. They have nearly stopped having kittens.

Possible solution

The impact people like Jones have made is apparent at Oakland Animal Services.

Over the past 10 years, the number of stray and feral kittens entering the shelter has been greatly reduced, said director Glenn Howell. He attributed this to the spay-neuter campaigns. However, the department's budget cannot match the demands put on it in summer, he said.

"We're talking about an explosion of kittens," Howell said, adding that about 10 kittens live in the shelter in winter, while more than 80 live there now.

The department depends on volunteer families to provide foster homes for the first couple months of a kitten's life. Young feral kittens still have a chance to be domesticated.

"They're not old enough to be adopted, but we still want to give them a chance of life," he said.

After foster care, the kittens return to the shelter. Too many kittens in the summer return without residents adopting them, said shelter volunteer Chris Flaningam.

"People who like cats are willing to take them in for a short time," she said.

Most adult feral cats don't get adopted, but get euthanized, she said. "The best they can hope for is to get captured and released."

The idea of returning feral cats to neighborhoods draws critics. The cats, which are not native, prey on native birds and create an imbalance in the environment, said Arthur Feinstein, director of conservation for the Golden Gate Audubon Society. He said ferals live unhappy, short lives where they need to scrounge for food and suffer health problems.

"When you put cats back outside, you're killing them anyway," said Feinstein, also a cat owner. "It's a slow death rather than a fast one."

The organization is not "anti-cat," Feinstein said. Society officials hope that one day organizations will set up sanctuaries for them.

Norfolk, Va.-based People for the Ethical Treatment of Animals, or PETA, opposes trapping and releasing unless people can manage the cat colonies with medical care, according to the organization's web site. Otherwise, they live with broken bones, internal injuries and infected wounds, among other ailments.

In the parking lot, one cat has lived among this colony for many years, Bates said. She and neighbors believe it's a mother cat. That's the one she said she hoped to catch.

As she does after each trapping, Bates plans to bring the cat home for the evening, then to a spay-neuter clinic the next day.

"We should be able to deal with this more humanely than wiping out the cat population each year," Bates said. Reach Bruce Gerstman at 510-748-1681 or by e-mail at bgerstman@cctimes.com.