Halloween came to our house early this year.
I am not superstitious. I have always been a cat lover. Yet if there is one thing I don?t want crossing my path right now, it?s another bored, carnivorous tourist, another recreational hunter on the prowl. Our yard is already a magnet for half a dozen neighborhood cats, all of whom I know to be pets with perfectly good homes of their own. But they are free to roam, while we, between our burbling bird fountain out front and our well-stocked bird feeders in back, just happen to look like a felid Six Flags ? now more than usual with the busy fall migrations under way.
I would like to complain to the cats? owners, demand that they come claw their property from mine, but I don?t. I?m a coward, complaining is unneighborly, and I?m all too aware that I could be accused of hypocrisy, of the pot calling the kitty black. Until she died two autumns ago, our cat Cleo was a notorious free ranger, yowling outside neighbors? windows, climbing on top of their roofs. We tried to make her a housecat, but when she retaliated by using our living room as a giant cat box, we cravenly sighed and flung open the door.
Had I known then what I know now, I would have held my ground, plugged my nose, and kept Cleo inside. Experts disagree sharply these days over how to manage our multitudes of stray and feral cats, with some saying off to the pound, others preaching a policy of catch, neuter and release, and everybody wishing there were other options to click. Yet when it comes to pet policy, and the question of whether it?s O.K. to let your beloved Cleo, Zydeco or Cocoa wander at will and have their Hobbesian fun, the authorities on both sides of the alley emphatically say, No. There are enough full-time strays; don?t add in your chipper. It is not fair to the songbirds and other animals that domestic cats kill by the billions each year. New research shows that neighborhoods like mine are particularly treacherous, Bermuda Triangles for baby birds.
Peter P. Marra, a research scientist at the Smithsonian Migratory Bird Center at the National Zoo, pointed out that cats were the only domesticated animal permitted to roam. ?Pigs have to stay in pens, chickens have to stay in pens,? he said. ?Why are cats allowed to run around and do what their instincts tell them to do, which is rampage??
It isn?t fair to the cat. Regular stints outdoors are estimated to knock three or more years off a pet cat?s life. ?No parent would let a toddler outside the house to run free in traffic,? said Darin Schroeder, vice president for conservation advocacy at the American Bird Conservancy in Washington. ?A responsible owner shouldn?t do it with a pet.?
In the view of many wildlife researchers, a pet cat on a lap may be a piece of self-cleaning perfection, but a pet cat on the loose is like a snakefish or English ivy: an invasive species. Although domestic cats have been in this country since the colonial era, they are thought to be the descendants of a Middle Eastern species of wild cat, and there is nothing quite like them native to North America. As a result, many local prey species are poorly equipped to parry a domestic cat?s stealth approach. ?People fool themselves into believing that by simply putting a bell on a cat they could prevent mortality to birds,? Mr. Schroeder said. ?But a bell ringing means nothing to a bird.?
Moreover, free-ranging domestic cats are considered subsidized predators. They eat cat food at home, and then hunt just for sport, a strategy that allows them to exist at densities far greater than carnivores achieve in nature. ?It?s estimated that there are 117 million to 150 million free-ranging cats? in the United States, Dr. Marra said. ?They?re the most abundant carnivore in North America today.?
Yet for all their indefatigable stalking, cats will rarely take on the most cursed vermin in our midst. ?The myth has been propagated that urban roaming cats do a lot to control the rat population,? Mr. Schroeder said. ?But science has shown that cats don?t predate on rats, especially not the rather large variety seen in our cities.?
Cats? toll on birds is a less mythical matter. In one famous study reported in the journal Nature, Kevin R. Crooks of the University of California, Santa Cruz, and Michael E. Soulé of the Wildlands Project in Colorado looked at the population dynamics among cats, coyotes and scrub birds in 28 ?urban habitat fragments? of Southern California. In the developments to which coyotes had access, free-ranging cats were rare and avian diversity high. The coyotes ate cats but rarely bothered with birds. Where coyotes were excluded, cats ranged free and bird diversity dropped.
Very likely, the cats got the young. As it happens, many temperate-zone birds go through a dangerous time early in life, when they are too big for the nest but still poor at flying. The fledglings spend their time on the ground, hiding in bushes and waiting for their parents to come feed them. People come upon the baby birds and think, poor dear, it?s fallen from its nest, but no, this is the system. ?They?re incredibly vulnerable,? Dr. Marra said, ?and in high-cat densities, the fledglings get nailed.?
In a newly completed study, Dr. Marra and his students used radio transmitters to track fledgling survival in two Washington suburbs: Bethesda and my own Takoma Park. The towns are similar socioeconomically and demographically, but while much of Takoma Park is crawling with outdoor cats, many streetscapes in Bethesda are, for reasons that remain unclear, largely cat-free. At least partly as a result of this discrepancy, Dr. Marra said, fledgling survivorship among Bethesda birds is about 55 percent, similar to what you would see in a natural population. But for birds that happen to be born in my tree-lined paradisiacal hamlet, only 10 percent last long enough to take wing.
There are ways to keep a cat happy inside. Becky Robinson, the founder and president of Alley Cat Allies, who has taken in five strays, recommends any number of the increasingly popular ?exclosures,? plastic pods that you pop into your window for the cat to enter and watch the world, or snaky mesh cages that you can even take camping.
I?m relieved to report that our new cat, Manny Jr., is content with our screened-in porch and the many hunting opportunities our home affords. Sorry, but the crickets are fair game.
http://www.nytimes.com/2009/09/29/science/29angi.html?_r=1&ref=science
PS As of 3:00 pm today, this has received comments from 448 NYT readers.
PPS I have been looking after 3 cats for the last few days. They are confined to a cat run.