Halloween cats may have been on the prowl last night. But every night of the year, a network of cat lovers works surreptitiously to ensure that the city's growing number of strays get more than the meager pickings from city trash cans and live to endure another day in the alleys of Washington.

The job is getting tougher now as the homeless cat population mushrooms under new cutbacks in the city's animal control division. Fewer low-cost clinics to sterilize pets and fewer city cat catchers mean more felines on the loose, said Jean V. Johnson, director of the Washington Humane Society, which runs the animal shelter.

A breeding female can give birth to 500 kittens during her lifetime, Johnson said.

"We have no idea how many there are out there -- thousands upon thousands," she said. "But when we drive through any alley we see them scatter." And most lead miserable lives, she added.

Enter folks such as Joanna Harkin, a legal secretary and part-time real estate agent, who is one of what some say are hundreds of city residents who have appointed themselves quiet guardians of an alley cat or two or more.

Harkin feeds about 15 every day near her Dupont Circle apartment. She got into feline social work two years ago when she sold a house in Adams-Morgan.

In visits to the house, Harkin noticed three female cats struggling to keep their litters alive in the alley. First she brought them food, then she decided to find them homes.

She ran a classified ad and placed most of the kittens within a few weeks. Now she runs such an ad almost every week and spends an hour or so on the phone every night trying to arrange placements of other strays or kittens of strays.

"Motherhood was thrust on me," she sighed.

But most of the time, she and the others work little miracles with 35-cent cans of tuna dinner and prefer to keep their activity unnoticed.

A group of elderly nuns at the House of the Good Shepherd in Georgetown feeds about a dozen cats near the convent. "But that's all I'll say on the subject," said Sister Louise Cecelia Greenfield.

A young woman in tight pants and spike heels near Logan Circle puts out food for a pair of cats in the crawl space under a nearby vacant house, then tells a reporter who asks for her name to "get lost."

And Tom Curtis, an administrative assistant who feeds about a dozen cats each day, said he does so "early morning or at night to avoid the stares."

Curtis and his friend Frances Chastang began feeding the cats when a friend who had been feeding them moved away.

The two say they walk about 2,000 miles a year in their twice-a-day rounds and spend about $2,200 for food and veterinary services. Their latest investment is a humane trap to catch breeding-age females to have them spayed. The shelter charges about $25, a third of the cost charged by a veterinarian, but it is open only one day a week.

"We live frugally more or less by nature, so we don't think about the cost," Curtis said. "I just couldn't live with myself if I walked by some gaunt little animal."

One of their regulars is a mild-mannered old cat with obvious tumors that lives on the porch of a vacant town house where Curtis believes it lived until its owner moved away or died.

On a chilly morning several weeks ago, the two waited almost 10 minutes for the cat to rouse and lumber stiff-leggedly down the long flight of stairs to be stroked and get dinner. "I'd spare him the trip down, but I don't go on private property any more," Curtis said. "I've been threatened once too often."

One night a man walked over to food they had just set out and threw it into a trash bin.

"Right in front of them; he knew exacty what he was doing," Curtis said. "I still have fantasies about hurting that man."

Dorothy Walsh feeds about a dozen cats that roam the Georgetown University campus, where, she said, she is notorious with authorities. During the summer, officials brought in exterminators to get rid of the cats, so she went around "shutting the traps."

"It's a constant battle to try to help them," she said.

For that reason, people in Baltimore who care for alley cats have formed a 1,500-member group called Alley Animals. In Washington, the networking is less formal.

"We've met several others on our rounds and sometimes strike up conversations with people we see buying a lot of cat food in the grocery store," Curtis said.

"I've met a lot of people, including some who give their whole lives to {stray} cats," said Ellen McPherson, who tends strays in Glover Park.

What motivates them, they say, is the alternative. Homeless kittens otherwise starve or die of disease or predators -- or brutal humans.

"You'd be surprised how cruel some people can be. For fun, they throw stones at cats and beat them to a pulp," Johnson said.

Things are so bad in the alleys, Johnson said, that she believes a homeless cat with no guardian is better off dead than alive. Each year the shelter euthanizes about 6,000, she said.

Curtis, Harkin and the others recoil at the thought.

Harkin said she hasn't even been able to bring herself to do it to one troublesome kitten she has not been able to place because he bites.

"I named him Boomerang because five new owners have sent him back," she said. "But I can't do him in."

So she just feeds and cares for him -- in the back alley.