It's Friday night in Eckington, a quiet residential corner ofWashington, and the back alley is crawling with feral cats -- rich pickings forseasoned cat-trapper Marty King."Here, kitty kitty kitty kitty," said King after setting four metal traps baited withflaked shrimp and fish cat food and lined with fresh newspapers."If they're hungry and they haven't seen traps before, they're not hard to catch," sheexplained."But some of them are very smart. There's a female I've been trying to get for acouple of years now and I haven't been able to get her yet."Within 20 minutes, a young gray cat takes the bait -- and by Sunday lands on aveterinary operating table to be spayed or neutered under an ongoing program tobring Washington's feral cat population under control.Coast to coast, the Humane Society of the United States estimates there are as manyas 50 million feral cats, or "community cats" as their advocates prefer to call them.That compares to 95.6 million cats kept as pets.For decades, standard procedure has been to round them up and euthanize them,but in recent years the trend has swung towards TNR -- trapping, then neutering,then returning cats to the places they were captured."Ultimately, our goal is to sterilize all outdoor cats and have them pass on throughattrition," Scott Giacoppo, vice president for external affairs at the WashingtonHumane Society, told AFP."So if our plan or our goal happens, there won't be any feral cats."- Bird lovers disagree -Not everyone is convinced. Bird lovers in particular see a proliferation of homelesscats -- neutered, sterilized or otherwise -- posing a deadly threat to many avianspecies.They cite a study from the Smithsonian Conservation Biology Institute and US Fishand Wildlife Service that estimated that "free-ranging domestic cats" kill a median of 2.4 billion birds and 12.3 billion mammals every year."Un-owned cats, as opposed to owned pets, cause the majority of this mortality,"said the 2013 study, published in the scientific journal Nature, which called TNR"potentially harmful to wildlife populations."The Centers for Disease Control has meanwhile asserted that "cats are more likely tobe reported rabid in the United States" than dogs. Others say feral cats are potentialcarriers of infection and parasites."The only sure way to simultaneously protect wildlife and people is to remove feralcats from the landscape," said the American Bird Conservancy in a petition sent inJanuary to Interior Secretary Sally Jewell."It's certainly a hot-button issue," acknowledged Elizabeth Holtz, staff attorney forAlley Cat Allies, a Washington-based group that promotes TNR and rejects the oft-quoted Smithsonian study as "irresponsible and biased."She cited the example of Jacksonville, Florida, which has seen "a huge decline inkittens entering their shelters and the number of cats they are euthanizing" since2009 under a groundbreaking TNR scheme called Feral Freedom."Unfortunately, many communities in the United States still continue to trap and killtoday, and those communities are not experiencing any change" in numbers of feralcats, Holtz told AFP.- Clipped ears -In Washington, every year, around 2,000 feral cats are trapped, sterilized, vaccinatedand released -- with a clipped left ear to show for it -- under the Washington HumaneSociety's Cat Neighborhood Partnership Program, or CatNiPP.The number has remained constant, something Giacoppo said might be due less tothe cat population than to a growing number of volunteer trappers coming forwardto help."It takes about five, maybe seven minutes for a female cat," said veterinarian Emily Swiniarski before 64 cats went under the knife one recent Sunday at the NationalCapital Area Spay and Neuter Center."For a male tomcat, it takes less than 30 seconds," she added matter-of-factly. "Itbecomes a real production line -- a lot of cats, coming and going, coming andgoing."Many cats get treated at the same time for various ailments."We see a lot of wounds," Swiniarski told AFP. "Occasionally we see old broken limbsthat have healed over time. Lately we've been seeing a lot of upper respiratoryinfections -- snotty noses, stuff coming from their eyes." As cats awaiting surgery meowed gently in towel-covered cages, Giacoppo recalledcoming across a 1930s law book that informed humane societies that "part of ourjob is to round up all the stray cats and kill them.""We've been doing that for years and years and it doesn't work," he said."We can't get people to help us trap cats to kill them -- but we can get people to helpus trap cats to sterilize them so they don't make any more babies.