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Outdoor cats are prolific killers, study finds
Free-roaming house cats kill an estimated 4 billion wild animals across the U.S. every year, including birds, mammals, reptiles and amphibians.
Wed, Aug 08 2012 at 12:57 PM
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Photo: Niels Hartvig/Flickr
Cat owners often wonder about their pets' secret outdoor lives, but few are curious enough to actually follow them around the neighborhood. And thanks to a new study by the University of Georgia and National Geographic, that isn't necessary: Researchers attached video cameras to 60 house cats that are allowed outside, hoping to learn how free-roaming felines spend their free time.
The answer? About a third of pet cats kill time by killing wildlife.
That may not surprise cat owners who regularly find tiny corpses on their doorsteps, but the study suggests house cats kill even more prolifically than many people realize. The researchers found the cats that killed did so about 2.1 times every week they spent outside, but brought home fewer than 25 percent of their kills. That could mean U.S. cats kill more than the previous estimate of 1 billion native birds and other animals every year — possibly as many as 4 billion.
"The results were certainly surprising, if not startling," says UGA researcher and lead author Kerrie Anne Loyd. "In Athens-Clarke County, we found that about 30 percent of the sampled cats were successful in capturing and killing prey, and that those cats averaged about one kill for every 17 hours outdoors, or 2.1 kills per week. It was also surprising to learn that cats only brought 23 percent of their kills back to a residence."
Working with National Geographic's Remote Imaging Department, Loyd and her colleagues attached lightweight video cameras (known as Crittercams, or "KittyCams" in this case) to 60 outdoor house cats in Athens, Ga. The cats' owners volunteered for the study by answering ads in local newspapers, and downloaded footage from the cameras at the end of each recording day. The study extended through all four seasons, and Loyd says the cats averaged five to six hours outside daily.
The cats killed a wide range of wild animals, including lizards, voles, chipmunks, birds, frogs and snakes (see the graph below). The study didn't include feral cats, but previous research suggests ownerless felines are at least as deadly as their more coddled cousins. A 2010 study by the University of Nebraska, for example, found that feral cats have driven 33 bird species to extinction worldwide, and that they prey more on native than non-native wildlife. In fact, since domesticated cats aren't native to North America, this leads some wildlife advocates to consider cats an invasive species themselves, on par with kudzu or Asian carp.
"If we extrapolate the results of this study across the country and include feral cats, we find that cats are likely killing more than 4 billion animals per year, including at least 500 million birds," says George Fenwick, president of the American Bird Conservancy, in a press release about the study. "Cat predation is one of the reasons why one in three American bird species are in decline."
"I think it will be impossible to deny the ongoing slaughter of wildlife by outdoor cats given the videotape documentation and the scientific credibility that this study brings," adds Michael Hutchins, executive director and CEO of the Wildlife Society. "There is a huge environmental price that we are paying every single day that we turn our backs on our native wildlife in favor of protecting non-native predatory cats at all costs, while ignoring the inconvenient truth about the mortality they inflict."
See the KittyCams website for photos, videos and data from the study. To get tips on keeping cats indoors, check out Ohio State University's Indoor Pet Initiative or the American Bird Conservancy's Cats Indoors Program. And if you know a cat that just can't be fenced in, you could at least attach a bell to its collar, or even dress it up in a bird-protecting "cat bib." (Fair warning: The cat may then want to kill you instead).
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hey less trips to the pet store!
Yes, cats kill wildlife. But which wildlife? Mostly, rats, mice and other small rodents, which are considered pests and people expend much effort to control. And rats are the primary predator of birds and their eggs. Overall, outdoor cats do for more good than harm.
I hope she sees how emotionless and dangerous feral cats are and turns her shepard loose to rid the neighborhood of them once and for all. they are more aggresive and dangerous than any stray dog. I will kill any feral cat i find on my property (and enjoy the service im doing) as there are so many, they have been deemed a public menace in my neighborhood
Gee I hope you know that killing a feral cat is deemed a Felony in all 50 states. I have been involved with the Trap Neuter Return of feral cats for over 20 yrs. Man"KIND" is the problem, not the cats-- spay and neuter these members of your pet family, and keep them indoors or in a secured area outside. Sorry about her bird, but that woman woman with the parrot is lucky an intruder did not come in thru those sliding doors.
Oh Please! It's humans that kill wildlife, not cats. All these stupid "studies" they come up with.. Eggs good for. Eggs bad for you. Next thing you will hear that dogs cause cancer!
A cat lover can't see beyond a cat!. That is the true even if we do not like it, cats are predators, there are some places were cats killed some specific kind of bird.
And it is the humans that allow cats to roam, and that feed cats in colonies for them to breed uncontrollably.
Cats in colonies are neutered. They do not reproduce and feeding causes them to hunt less, not more.
I guess that would make the human race, cow, pig and chicken killers, right?
AND HOW MANY WILDLIFE DO HUNTERS KILL, MORE THAN CATS. LETS BE HONEST AND PUT IT IN PROSPECTIVE
Can we think back to what happened the last time people hated cats and killed them all???
hmmmm.... THE PLAGUE!!!!
You know, I thought it was pretty obvious that WE are the problem, but what the heck, let's blame the cats and cats alone. Now I know that the large amount of feral cats are indeed a big factor in the decline of wildlife, but to say that reducing this amount is a solution, without considering our own influences is typically stupid. We expand like crazy: less habitat for birds and such, more aeroplanes to knock em out of the sky etcetera etcetera take your pick.
Wait a minute.......you're saying cats kill birds??? Since when?? Oh yeah, since the beginning of time. In related news, a bird was seen devouring a lizard. Now THAT makes me mad. My indoor/outdoor cat drags in a bird, mouse, lizard, rabbit or bat at least three time a week to share with her housebound mates. I couldn't be prouder of her. She's the only real cat out of the four.
Cats where domesticated for the sole reason of killing rats and mice in the home, let it do what it was born to do.
I now want 5 more cats.
Russ better check his math. The numbers don't add up. Not even close.
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