Nobody knows how many are out there or how much damage they do.
They are stealthy, nocturnal predators; often diseased; sometimes despised; living and breeding in dumps and abandoned buildings, by apartment dumpsters and barns; avoiding humans, even those trying to help them.
We're talking about feral cats, and by some estimates there could be as many as half a million in Connecticut alone.
One expert calls the issue a "clandestine problem" because most people never even see these furtive creatures, or if they do spot them, just assume they're somebody's domestic kitty out for a stroll.
There are birding enthusiasts who'd like to see every last feral feline rounded up and killed to stop what ornithologists believe is the wholesale slaughter of our native wildlife. Feline lovers are equally fierce in defense of feral cats, lobbying against federal and state regulations or laws they fear might justify mass euthanasia, arguing that "managing" the problem through sterilization is the best and most effective response.
About the only things the bird geeks and cat freaks agree on is that there's no easy solution, and any serious attempt to dramatically reduce feral cat populations is going to cost a lot of cash.
According to one state official, Connecticut may be the only state in the nation attempting to control feral-cat populations by subsidizing efforts to capture, sterilize and release these wild felines. Last year, the state Department of Agriculture's program spent something like $80,000 on spaying and neutering nearly 1,000 feral cats.
If unofficial guesstimates by scientists and experts are correct, that between 330,000 and 500,000 feral cats are roaming Connecticut, then this state's sterilization program is less than a drop in a big freaking bucket.
"It's a complicated issue," admits Jenny Dickson, a wildlife biologist with the state Department of Energy and Environmental Protection. She calls the idea of trying to kill all the feral cats in Connecticut to protect endangered or threatened native species "a very difficult question" and one that may simply never work.
"People have caused the problem," insists Donna Sicuranza, president of a non-profit mobile clinic that's been working on sterilizing Connecticut's feral cats for the past 15 years. "It's not the cats' fault."
Bob Johns, spokesman for the American Bird Conservancy, says new scientific studies by the Smithsonian Institute and others indicate the number of birds being killed by feral and free-roaming domestic cats may be even more staggering than the 500 million to one billion birds a year previously estimated. He also agrees that the only real solution is changing the behavior of cat owners.
We've got something like 70-90 million domestic cats as pets in the U.S. Another 60 million or more may be feral, and they're all descendants of "beloved" pets that were dumped by their owners, or allowed to stray, or just got lost.
So the abandoned animals are left to scavenge and hunt to survive. They frequently band together in "colonies" that can sometimes number in the hundreds. Unless they're spayed or neutered, they rapidly reproduce. Unless they get vaccinated, they often become diseased with things like feline HIV, hookworm, occasionally rabies, and other conditions that can spread to domestic animals.
(Rabies among feral cats is a risk because they're more likely than domestic cats to come in contact with so-called rabies-vector species like raccoons and skunks. Of the 195 animal rabies cases recorded by the state in 2011, only seven involved cats, domestic or feral, according to state public health statistics.)
Between disease and the risk of being eaten by coyotes, hawks, bobcats, foxes or fisher cats, the life spans of feral felines are often less than half that of domestic cats, which can frequently live 15 years or more.
And it doesn't take long for the offspring of strayed or abandoned cats to become truly feral.
"Feral cats go out of their way to avoid you," says Sicuranza. "They only come out at night and they avoid people at all costs." She points out that, unless a kitten is "socialized" through human contact in the first few months, that animal is unlikely to ever become an affectionate house tabby that someone might want to adopt.
The biggest reason why it's so tough to control feral cat populations is that human pet owners keep on doing the same irresponsible things, feeding an apparently endless supply of abandoned cats into the feral pipeline.
"What we're saying is that local communities need to take far more responsibility than they have in the past for feral cats," Johns insists. He argues that simply feeding and sterilizing feral cats isn't going to solve the problem. "It isn't going away, and it's only going to get worse," says Johns. "Euthanasia may be a last resort, but if that's what it takes…"
The trouble is that, even if you could kill all the crafty feral cats in an area, more would likely arrive and the problem would continue.
Eradicating every feral cat might also not solve environmentalists' complaints that hundreds of millions of native North American birds, mammals and reptiles are being slaughtered every year by cats.
Cat advocates, by the way, insist feral felines don't murder anywhere near as many birds as some claim. They have their own conflicting studies of feline predation that indicate that humans are more damaging to bird populations: Bird habitats are lost to human development, pollution and hunting, and migratory birds collide with things like transmission towers, buildings and wind turbines.
There's also the argument that feeding feral cats living in "managed" colonies makes them less likely to hunt. If they do hunt, say cat advocates, their targets are mostly rodents like mice and rats, which is what we originally kept cats around to do back 5,000 years ago.
Another issue is that a great many of those wild bird kills are perpetrated by domestic kitties allowed to roam free. The Audubon Society and the American Bird Conservancy have launched repeated campaigns to get people to keep their cats indoors as a way of stopping the slaughter, but not all cat fanciers agree.
Sicuranza sounds conflicted on the concept. She keeps a couple of office cats indoors all the time because her Westbrook headquarters is on a busy road, but lets her house cat out sometimes. "I think any animal should be able to get out in the fresh air a little bit," she says.
Attitudes like that can drive birders and environmentalists nuts. American songbird populations have been plunging and, while free-roaming cats are probably not a dominant reason, experts like Dickson are convinced they are killing lots of birds. "It can be significant," Dickson says, citing the findings of numerous researchers that cats do hunt and kill large numbers of birds and other wild creatures.
The key argument of cat advocates is that feral cat colonies can eventually be eliminated through "trap, neuter and release" or TNR programs. That's where humane traps (the most well-known being the Havahart brand) are used to capture feral felines, which are taken to a vet for sterilization and vaccination, then released.
Kerry Bartoletti, one of the founders of the Friends of Feral Cheshire Cats group, says her organization has used TNR on about 2,500 cats in the past six years.
She says the success of such programs is clear, pointing to one feral colony on Route 10 that originally had perhaps 60 animals but is now down to about nine cats. "We haven't had a kitten born there in five years," she says.
Sicuranza says her "TEAM Mobile Feline Unit," which travels around the state to perform cat sterilizations and vaccinations, has performed those operations on more than 150,000 feral cats over the years.
The TEAM unit charges $80 per cat for both sterilization and vaccinations, and uses vouchers (when they're available) from the state's feral-cat program to help people pay for the treatments. If that sounds expensive, consider that regular vets may charge $100 or even $300 for the same sort of treatments, if they're willing to deal with unruly feral animals at all.
"Really, the only way to solve the feral cat problem is trap, neuter and release," says Sicuranza, "but it's not easy."
"There's a high rate of burn-out for folks doing the trapping," she explains. In order for TNR to work with managed feral colonies, it has to be an ongoing, determined effort, and these are not easy animals to handle.
Sicuranza says the number of ferals being brought in to her organization as part of TNR efforts has dropped in recent years. "I'd like to think we've cleaned up some areas… that the numbers of feral cats have been reduced in Connecticut."
Of course, environmentalists insist they have plenty of studies demonstrating that most TNR and managed-colony programs very seldom work. "I'm not convinced, based on what I've seen, that it's the most effective way to go," says Dickson.
Public officials often shudder when asked about feral cats, knowing from bitter experience what kinds of passions the issue can arouse.
And, of course, the size of the feral cat population continues to be a mystery.
"No one really knows how many feral cats are in Connecticut," says Frank Ribaudo, supervisor of the state's Animal Population Control Program.
Ray Connors, supervisor of the animal control unit in the state Department of Agriculture, explains that checking with local pounds and animal-control officers doesn't help much. Municipal officials are required by state law to capture stray dogs, but not stray cats, and few towns require that either.
One official of the American Society for the Prevention of Cruelty to Animals estimated a couple of years ago that there were approximately 330,000 feral cats in Connecticut. Another expert uses the formula of .5 feral cats per household, which results in that half-a-million figure.
"I don't doubt those numbers," says state Rep. Mary Mushinsky, a Wallingford Democrat who's been working on the feral cat issue for years. "I think it is a big problem."
She argues the state needs to get serious about licensing cats, saying all those feral felines "are a direct result of domestic cats being unregulated." Of course, cat lovers across the state have resisted that sort of state action, worried about what might happen to all their unlicensed feline buddies.
One thing is sure: all those hundreds of thousands of sneaky feral kitties out there aren't going to vanish on their own.
"Feline overpopulation was a serious problem 15 years ago," says Sicuranza, "and it still is."