By

Tia Ghose /

Livescience.com/ January 29, 2013, 1:51 PM

Study: Cats kill billions of animals a year

Cats kill billions of birds every year and even more tiny rodents and other mammals in the United States, a new study finds.

According to the research, published Tuesday in the journal Nature Communications, cats kill between 1.4 billion and 3.7 billion birds and between 6.9 billion and 20.7 billion small mammals, such as meadow voles and chipmunks.

Though it's hard to know exactly how many birds live in the United States, the staggering number of bird deaths may account for as much as 15 percent of the total bird population, said study co-author Pete Marra, an animal ecologist with the Smithsonian Conservation Biology Institute.

Staggering toll

Marra and his colleagues are looking at human-related causes for bird and wildlife deaths in the country, from windmills and glass windows to pesticides.

But first, Marra and his team looked at the impact of the feline population, one of the biggest putative causes of bird demise in the country.

While past studies had used critter cams or owner reports to estimate the number of birds killed by cats, those studies were usually small and not applicable to the entire country, Marra told LiveScience.

For this broader analysis, the team first looked at all prior studies on bird deaths and estimated that around 84 million owned-cats live in the country, many of which are allowed outdoors. "A lot of these cats may go outside and go to 10 different houses, but they go back to their house and cuddle up on Mr. Smith's lap at night," Marra said.

Based on an analysis of past studies, the researchers estimated that each of those felines killed between four and 18 birds a year, and between eight and 21 small mammals per year.

But the major scourges for wildlife were not those free-ranging, owned-cats, but instead feral and un-owned cats that survive on the streets. Each of those kitties -- and the team estimates between 30 million and 80 million of them live in the United States -- kills between 23 and 46 birds a year, and between 129 and 338 small mammals, Marra said.

And, it seems, the small rodents taken by felines aren't Norway rats or apartment vermin, but native rodent species such as meadow voles and chipmunks, he added.

No easy answers

One obvious step to reduce the mass wildlife death is to keep kitties indoors, Marra said.

Perhaps seeing their furry friends bring in a meadow vole or a cardinal will spur cat owners to say, "Listen, Tabby, we're going to have a heart-to-heart talk about how much time you spend outside," he said.

Wild cats pose tougher questions, because capture and sterilization approaches have varying levels of success depending on the community, said Bruce Kornreich, a veterinarian at Cornell University's Feline Health Center, who was not involved in the study.

While keeping owned-cats indoors is the best way to benefit both kitties and wildlife, a complete cat ban, like the one recently proposed in New Zealand, is probably not the answer, he said.

For one, it's not clear how completely removing cats from outdoors would affect the ecosystem.

"It may be in some cases that cats may also be keeping other species that may negatively impact bird and other small mammal populations in check," Kornreich told LiveScience.

Livescience.com. All rights reserved.
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zoezoe1212 says:
Those studies are BS. How can they say that cats are killing chipmunks and not Norway rats and house mice? I saw first hand that cats are vital to keep rats & mice at bay. Someone did a stray cat round-up in my old neighborhood in NYC. A week later when I walked down the street there were mice hopping on the sidewalks. It is sad to humans, but there are subway cats that live underground in the tunnels and live on rodents (big subway rats too!)and never see the light of day.I got this from a transit worker that saw them every day. The main reason I have always had a cat is they kill rodents and bugs. Why judge cats by human standards? My cat brings whatever she catches to me as gifts. She thinks killing is wonderful, as she should, it's what she was made for. She has brought me mice, dragonflys and only once a sparrow that was probably sick. She will eat moths and crickets. They are great pests to humans. It would be logical that strays eat a lot of harmful insects also. I always supervise my cats outside. I now have a cat friendly patio with plants and sun and they usually just hang there.
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LeeMrk replies:
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Here is further proof. This article is "unsuitable for publication" based on significant statistical flaws. http://www.alleycat.org/document.doc?id=633
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ownedbycats says:
It's real simple. The networks are trying to upset cat lovers with this story. It is not a "news" story. The study is not based on clear evidence of anything. It was a waste of taxpayer dollars to begin with. Now the news media is trying to use it to emotionally manipulate people ... to cause a standoff between cat lovers vs. cat haters. They are creating this out of thin air and using this flimsy study to do it. PEOPLE BEWARE: The news influences the way you think more than you know. They inject their personal agenda in to everything they report. You no longer get an unbiased reporting of the facts. The facts are emphasized as they see fit to produce the reaction from people that they want. This whole cat vs. bird BS proves it. Example: Did they emphasize that cats kill 5x more rodents than birds, and if cats weren't on the job, we'd be knee deep in rats, mice, gophers, etc? I don't know about you, but I see plenty of birds in my yard. I don't, however, see mice, rats or gophers.
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miafarrah says:
Also,let me add that billions is not correct.They would have to know how many cats are in the country to accurately know how many species they killed.They don't really know,it is impossibe to really know.Nothing better else to print about except how cats can be bad????Cat have to hunt if thier homeless and have no other means of survival.There is a big difference.I didn't know cats just came into existence.I better stop here before i get banned from this website.This is a personal attack on cats.
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miafarrah says:
Someone is starting trouble for cats that printed this aticle.Oh..wow they chase after spiders,moths and flies so their serial killers! Why not print how may cats are killed by humans every year??????Why not give out statistics how many human predators there are out there that know what their doing? Where as cats are by nature natural predators.Why not give statistics how many human predators out there that stalk other humans? Oh, and let me not to forget the hunters that prey on and hunt deer,elk,moose,squirrels, rabbits,wolves and other people when they get the opportunity to kill? How about how many cats suffer because of humans that are irresposible pet owners????Is it wrong just to be a cat?? Dogs are fine animals too but they can chew on socks or whatever at home and so can't puppies.But to say cats kill billions as if thier serial killers is a bad article,there are many that love their cats and i'm one.So you all had better accept that a cat is just being what he is made to be.
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displeased2 replies:
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Have all the cats you want, just keep them in your own yard and out of mine.
displeased2 replies:
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Actually, I attract birds, squirrels, and chipmunks to my yard with my natural habitats. The neighbor's cats come to my yard to hunt. I've thought about trapping the cats and taking them to the pound.
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Deadstick325 says:
And yet the skies are still filled with birds and rodents abound. What, exactly, is the problem?
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ownedbycats replies:
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Empire_George: And the liberal news media used it as an excuse to emptionally manipulate the masses.
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SiriuslyPOed says:
I cannot believe people are defending cats running loose. Of course, so many people do just that, so perhaps I shouldn't be surprised. Cats aren't just killing mice and rats; they are killing rabbits and birds. They also like to spray anything anyone leaves on my front porch, and take craps in my gardens. Why does anyone think this is ok or neighborly?
It is also dangerous to allow your cat to roam. Foxes and coyotes grab them, cars hit them and they fight (preferably, it seems, at 3 a.m.).
I keep my cats in for these reasons. To do otherwise is selfish and foolish.
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displeased2 replies:
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George, if my dog is not allowed to go in your yard, then why should your cat be allowed in mine? So if your cat wanders in my yard, you won't have a problem with me shooting it? And your response is that of the typical cat owner, inconsiderate and angry.
ownedbycats replies:
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Displeased2, if your dog came in my yard, I would not shoot it. It is a living creature, and it can poop on my lawn if it so desires. I may not like it, but I don't like liberals either. Doesn't mean I go shooting them. But I can tell you one thing right now: If you think cats are vicious, wait until you get a load of a catowner whose cat has been shot. You'd be looking down the barrel of my Ruger SP-101 ... one-click head shot. Don't be thinking us catowners are *******.
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Cataptra says:
So we blame this ALL on cats, what about dogs? Why are they not mentioned? Have you not seen a dog chase down and kill rodents, birds or other animals? They do it to.

So those yelling all cats should be banned, well, if you're a dog lover, then sorry, but your dog needs to go as well.

So let's just ban all pets shall we?

Now just how idiotic would that be?

I don't care what anyone says, it's NOT so much pets or animals doing the destruction or the extermination/extinction of any other animals.

It is humans, especially developers that continue to destroy and get permits to ear down natural habitats for these animals, then since there homes have been destroyed, start integratting with humans by building nests or slithering into your home, then we go and buy traps, bait or guns to rid ourselves of a pest, which in all rights lived there BEFORE the development was ever thought about, but now taken over these animals residential areas.

So leave folks pets and cats alone, unless you're willing to give up every pet or any other animal you might own.

After all, what about snakes that many owners have released into the wild?

For example because they found out later after acquiring said snake or animal it wasn't for them, cost more than they expected to take care of, or just tired of it and released it?

These animals I'm sure have caused just as much, if not more deaths of other creatures as any cat.

There is a reason and a place for everything, but the wanton destruction of animal habitats and human development has been the demise of many an innocednt animal, so we should be looking at ourselves just as hard, if not harder than any pet we own or animal on the prowl.
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SiriuslyPOed replies:
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I keep my dog, as I do my cats, in my home and yard so as not to intrude upon my neighbors. No one is talking about banning cats, but your defensiveness is off the charts here, so you must be one of those people who allows your cat to spray everything on my front porch.
I must tell you, too, that I once had a dog (that I kept in my yard) that killed cats. He got three in his lifetime that had roamed into my yard. All I could think was how irresponsible those cats' owners were.
If you are going to have a pet, be responsible about having it.
How utterly desperate for you to bring snakes into this "argument!" ha!
Cataptra replies:
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Sorry MY CATS DO NOT ROAM the neighborhood and were neutered as soon as they became of age to do so. They are INDOORS ONLY and only go out if they are ON A LEASH as per the leash laws where I live. So sorry to burst your bubble, but I have been an extremelhy responsible pet owner since the day I started having a pet. Unlike the sorry dog owners in my neighborhood whose dogs are continually OFF LEASH, a violation of the law, as well as allowing them to take a sh*t in MY yard and NOT CLEAN IT UP, again a violation of law. Nor was I as defensive as you so try to blatantly point out, just fed up with IRRESPONSIBLE PET OWNERS, despite the type of pet owned and that HUMANS are the main downfall of animals that are going by the wayside or have become extinct to overhunting, etc. So say what you want, I know where I stand and I know my cats can't spray anyones property because they were fixed as soon as they came of age to be neutered. And I used to have dogs, I just prefer cats because I don't have to take them for walks out in inclement weather such as rain, freezinfg cold, etc. Just easier to take care of. But that's just my and my spouses opinion on that score.
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Rocket_USA says:
After I saw the headline I had to come just for the comments section...it didn't disapoint!!!
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SiriuslyPOed replies:
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No kidding! All the "crazy cat people" left their scratching posts and came out!
SiriuslyPOed replies:
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The "crazy cat people" left their scratching posts and came out in numbers.
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tudognight says:
Ferrel cats do not have the size or strength of a well fed pet cat and not are as good a killer. A healthy bird is less likely to become cat prey than an weaker or sick one. Unhealthy birds carry diseases that can contaminate our domestic food birds (ie: Chickens,ducks, and turkeys). Ancient Egyptians kept cats as they wanted their grains free from rodent droppings and disease. Like dogs, cats have been us humans for centuries and as goes their fate, so goes ours. Simply put we need them. They historically have been a part of our story of survival.
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tudognight says:
Obviously, most of you are forgetting about decades of health plagues from rodent populations. Rabies is another thing nature gave us. Any grain farmer worth his salt will own a dozen outdoor cats. Well fed cats by the way make the best rat and mouse killers. So unless you want a disease driven reduction of human population, you ought to leave the cats alone. Cats on farms are subject to hawks killing them, farm machinery killing them, and lots of fights lost to predators in nature. The fact that we have not had large death of humans from diseases of the past is a result of a large cat population. And with birds.....ever heard of bird flu and the cross contamination of human populations a few years ago. The wild birds infected the chickens, the chickens infected humans.....humans died.....we missed a world epidemic....leave the cats alone fools.
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