getting wild in the city
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Cats kill birds

Deer destroy plants

Raccoons deal death




 


Does this look familiar? Cats are sophisticated hunting machines, and birds just can't protect themselves.

Photo by Marge Gibson, courtesy of the American Bird Conservancy.

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Cats and birds
6 MAY 1999. Washington's cherry trees seem safe, at least for the moment, from those clear-cutting beavers. Because urban wildlife can cause lots of problems, this Why Files delivers the scoop on carnivorous cats, damaging deer and the festering feces of raccoons.

You don't need an IQ of 200 to recognize that lions are like house cats on steroids. Lately, biologists have noticed another similarity between the ferocious felines and their domesticated cousins: Just as the lion is the top dog, so to speak, of the African savanna, the house cat is the master predator of the American farmscape, and presumably of the cities and suburbs as well.

Sylvester and TweetyWhat lions accomplish through size and cooperative tactics, cats accomplish by numbers. More than 100 million cats are afoot in the United States, and many are outside at least part of the day. Most domesticated cats gobble endless bags of cat chow. But they also like dining outdoors where their meals comprise 70 percent small mammals, 20 percent birds, and 10 percent assorted live bait.

That 20 percent adds up to a lot of birds, according to research on free-ranging rural cats by Stanley Temple, a professor of wildlife ecology at the University of Wisconsin-Madison. Using telephone surveys and more traditional tools of the wildlife biology trade like radio collars Temple came up with a "most reasonable estimate" that cats annually kill at least 7.8 million birds in Wisconsin alone.

That's a lot of flying feathered objects. In summer, Temple says, about 19 million birds produce 16 million young in Wisconsin, for a total of 35 million birds. If, as he calculates, cats kill about 3.3 million birds in the summer, that accounts for almost 10 percent of the summer population.

Ground-nesting species like meadowlarks -- already under pressure for other reasons -- are particularly vulnerable. But Temple observes that the problem extends beyond birds, since cats are also pressuring rare species like the marsh rabbit of Key West, and more common but harmless mammals like field mice and meadow voles.

Does this make cats the top dog? Temple says in the farming districts he studied in Wisconsin, cats outnumber and outkill foxes, raccoons, skunks and all other mid-size predators combined. But beyond numbers (up to 114 per square mile), cats are immune to controls that affect other predators.

People protect some free-ranging cats from disease and competition. And cats, which Temple describes as "subsidized predators," can prosper even when prey is scarce. Normally, the population of predators tracks that of prey: When the prey population crashes, the predators go hungry, and their numbers fall, reducing pressure on the prey.

Cats, however, "are not tied closely to the density of prey the way natural predators are," Temple says. "A natural predator will hunt where prey is abundant," Temple says. "A subsidized cat has the ability to hunt anywhere. If there's one last meadowlark in the field, they will continue to hunt it."

Since many free-ranging cats also eat from a bowl, hunting is not a matter of life and death -- for them. They kill because they are programmed to hunt, not because they are hungry.

What's to be done?
Although there's little hard data on the effects of urban and suburban cats on birds, cat owners and bird lovers alike know that these cats kill wildlife just like their rural relatives.

Concerned cat owners (like some Why-Filers we could mention) have been strapping bells to their kitties for many years, but experts maintain that bells are useless. "Bells don't work -- I wish they did," says Linda Winter, the coordinator of the American Bird Conservancy's Cats Indoors campaign. "Cats can learn to silently stalk their prey, and birds don't associate the sound of a bell with danger," Winter says. "Even if they do ring, it may be the last sound a bird hears."

Bird lovers and cat lovers alike say neutering cats will prevent the birth of countless unwanted cats. For the millions of existing cats, the big lock-up is the best -- and perhaps only -- way to protect birds and wildlife from furry feline snuff squads.

That's right. Slamming the door in the poor creatures' faces.

Many cats are surprisingly susceptible to indoor training, says Winter, a cat lover herself. "For some, it's simply a matter of closing the door and putting up with some howling for a few days." For others, a few months' acclimatization is needed. Kittens are the easiest to train, she adds, since they don't know what they are missing if they're never allowed outside.

Need a woodland cleared of underbrush?
Call 1-555-555-DEER.


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The Why Files Staff includes: Terry Devitt, editor; Darrell Schulte, webmaster; David Tenenbaum, feature writer