Sign up for our Free email Newsletter
and get all the latest wildlife news!

Browse Old Articles


Cats kill 2.4 billion birds and 12 billion mammals every year in US alone

29/01/2013 16:09:49

Cat with American Coot by Debi Shearwater.

Outdoor cats: Single greatest source of human-caused mortality for birds and mammals, says new study
January 2013. A new peer-reviewed study published and authored by scientists from two of the world's leading science and wildlife organizations - the Smithsonian Conservation Biology Institute and the U.S. Fish and Wildlife Service (FWS) - has found that bird and mammal mortality caused by outdoor cats is much higher than has been widely reported, with annual bird mortality now estimated to be 1.4 to 3.7 billion and mammal mortality likely 6.9 - 20.7 billion individuals in the US alone.

The study, which offers the most comprehensive analysis of information on the issue of outdoor cat predation, was published in the online research journal Nature Communications and is based on a review of 90 previous studies. The study was authored by Dr. Peter Marra and Scott Loss, research scientists at the Smithsonian Conservation Biology Institute and by Tom Will from the U.S. Fish and Wildlife Service's Division of Migratory Birds.

Propblem is even worse than previously suspected
According to Dr. George Fenwick, President of American Bird Conservancy, one of the leading bird conservation organizations in the U.S. and a group that has called for action on this issue for many years, "This study, which employed scientifically rigorous standards for data inclusion, demonstrates that the issue of cat predation on birds and mammals is an even bigger environmental and ecological threat than we thought. No estimates of any other anthropogenic [human-caused] mortality source approach the bird mortality this study calculated for cat predation."

"To maintain the integrity of our ecosystems, we have to conserve the animals that play integral roles in those ecosystems. Every time we lose another bird species or suppress their population numbers, we're altering the very ecosystems that we depend on as humans. This issue clearly needs immediate conservation attention," he said further.

"The very high credibility of this study should finally put to rest the misguided notions that outdoor cats represent some harmless, new component to the natural environment. The carnage that outdoor cats inflict is staggering and can no longer be ignored or dismissed. This is a wake-up call for cat owners and communities to get serious about this problem before even more ecological damage occurs," Fenwick said.

The study's estimate of bird mortality far exceeds any previously estimated U.S. figure for cats. In fact, this magnitude of mortality may exceed all other direct sources of anthropogenic bird and mammal mortality combined. Other bird mortality sources would include collisions with windows, buildings, communication towers, vehicles, and pesticide poisoning.

2.4 billion birds and 12 billion mammals killed by cats
The study estimated that the median number of birds killed by cats annually is 2.4 billion and the median number of mammals killed is 12.3 billion. About 69 percent of the bird mortality from cat predation and 89 percent of the mammal mortality was from un-owned cats. Un-owned cats are defined to include farm/barn cats, strays that are fed but not granted access to human habitations, cats in subsidized colonies, and cats that are completely feral.

Extinction cause
Free-ranging cats on islands have caused or contributed to 33 (14 percent) of the modern bird, mammal, and reptile extinctions recorded by the International Union for Conservation of Nature Red List of threatened animals and plant species.

Native species make up the majority of the birds preyed upon by cats. On average, only 33 percent of bird prey items identified to species were non-native species in 10 studies. Studies of mammals in suburban and rural areas found that 75-100 percent of mammalian prey were native mice, shrews, voles, squirrels, and rabbits, all of which serve as food sources for birds of prey such as hawks, owls, and eagles.

The study charges that, "Despite these harmful effects, policies for management of free-ranging cat populations and regulation of pet ownership behaviours are dictated by animal welfare issues rather than ecological impacts.

Projects to manage free-ranging cats, such as Trap-Neuter-Return (TNR) colonies, are potentially harmful to wildlife populations, but are implemented across the United States without widespread public knowledge, consideration of scientific evidence, or the environmental review processes typically required for actions with harmful environmental consequences."

Read the comments about this article and leave your own comment

I recently found a lot of useful information in your website, especially this blog page . Among the many comments on your articles. Thanks for sharing .

Cara Membuat Akun Facebook:
Cara Membuat Akun Twitter :
Paket Internet Smartfren :
Paket Internet 3 :
Hp Lenovo Murah Berkualitas:
Paket Internet XL :
Paket Internet IM3 :
Cara Download uTorrent :
Aplikasi Antivirus Android Terbaik :
Aplikasi Download Video :
Aplikasi Edit Video Android :
Aplikasi Edit Foto Android :
Aplikasi Android Terbaru :
Game Strategi Android :
Cara Instal Windows 7 :
Cara Promosi di Facebook :
Cara Membuat Akun Facebook :
Apa itu Internet Marketing :
Cara Membuat Blog :
Harga Apple iPhone 6 Terbaru :
Kecanggihan iPhone 6 :
Aplikasi Download Lagu Android :
Software Animasi Terbaik :
Kecanggihan iPhone 6 :
hp android harga 1 jutaan :
Jadwal Motogp :
Cara Membuat Email :
Cara Root Android :

Posted by: kdrcyber | 14 Nov 2015 03:06:50

Coyote Food and You Get Back What You Give To Your Cat

What a lot of people in the US do not realize is that cats are eaten by coyotes. Outdoor cats, feral cats, and barn cats are eaten in my area of the Olympic Peninsula, even in the local towns, by coyotes. I do not think that outdoor cats are a problem in the mainland US. Other countries, and islands, I do believe that they are a problem. In Hawaii there are cat colonies eating the sea birds and also they eat the local introduced birds in the jungles and towns. There is an island of catch and spay/neuter on the southeast coast that want the stray cats to help keep the rat population down. That is why they have them in Hawaii also I recall. Thing is cats need to be kept indoors so they don't eat the birds around your home. Most birds at feeders figure it out, but there are the ground birds that don't. I own 2 cats, and they killed less than a dozen birds a year and ate voles that were in the garden, native mammals that were overabundant eating up my garden. They also kept the birds out of my garden that ate my blueberries and strawberries. I keep my cats indoors now because a coyote tried to kill one of them. We have a rural area to live in, and that is just how it is. I think the catch and release from neuter/spray is an expensive gourmet dish for a coyote later on. Cats should be rehabilitated to indoor life, or they end up in humane catteries, instead of being let out as coyote food. I love my cats, so they live inside. I also love birds, and the predator birds and the other birds have increased in population in my area since then. However, we now have to pay for a rat control person, since the cats were not around to patrol the yard for vermin. Also you treat a cat like a companion/dog, and they act like one. You treat them like they are just something to decorate or amuse you, and your cat will treat you like you treat them.

Posted by: Pamela Paskell | 05 Feb 2013 04:08:44

Too much inaccuracy!

Beware the double consonant ;-)!
As I read the article I conclude that the median figure referred to would probably be backed up by most of the ninety studies concerned, leaving the outside estimates to be the exteme variation in results. Even if the lowest figure were the most accurate, it is still a formidable loss of wild birds to a predator not natural to the environment.
Here in Ireland we have approached the extinction of some of our breeding wildfowl through predation by feral mink. No one, except the loony people who "liberated" the mink from farms, objects to culling of these animals. Why can cat people not see their pets for the predators unnatural to our environment that they are and control them?

Posted by: Dermot McCabe | 04 Feb 2013 21:24:26

too much innacuracy

(Beware the return key!).

With the amount of acknowledged uncertainty in every factor of these tests from actual numbers of animals to true predation rates, these figures are more projections than estimates.

As stated, a difference in conclusion numbers that varies by nearly 300 percent suggests a vagueness of focus.

Reasonable variances are a few tenths of a percentage point; acceptable variances are under twenty percent. 300 percent variance misses by miles.

It's logical to assume predators nab more birds and mice than what we are able to observe--but to project actual values without acknowledging that we are guessing is pretty softcore science.

Posted by: bando shamaly | 04 Feb 2013 17:54:14


A mere statement that results are "impossibly variant" does not prove them impossibly so. If the results of the study are implausible or incredible, show how this is the case. Address the issue that such mainstream institutions and named scientists are so unprofessional and that peer reviews make no mention of this.

Posted by: Dermot McCabe | 04 Feb 2013 11:50:45

more hyperbole

That different studies of an identical phenomenon should yield such impossibly variant results: it beggars plausibility, it beggars credibility.

Posted by: bando shamaly | 04 Feb 2013 05:23:42

What's in dispute?

The article states that the figures are based on 90 (NINETY) different studies - not 1 (ONE) study with wide ranging results.
The variation is perfectly understandable in this context.

Posted by: Dermot McCabe | 03 Feb 2013 20:36:25

what's in dispute here?

That felis domesticus is an apex predator? Hardly.

That these estimates differ by such a hyperbolic amount? Absolutely.

If you were traveling to destination X and were planning the amount of fuel you'd have to carry to get you there based on someone's estimate that the distance was between 300 and 900 miles, you'd look for a better estimate.

Posted by: bando shamaly | 03 Feb 2013 18:45:42

Study dismissed?

A peer reviewed study by reputable institutions is hardly likely to be so grossly unscientific as some correspondents suggest. It is not conceivable that falsehoods or errors of the kind described could get into circulation without major and widspread criticism. Imagine for a moment a similar study concerning rats was in discussion. Can anyone think that the science would be so immediately and scathingly pooh-poohed? Why the bias in favour of cats?

Posted by: Dermot McCabe | 03 Feb 2013 18:05:19

mea culpa: it's yearly, not daily!

Friend who linked this message told me the figures were per day, not annually, hence my error.

But my skepticism of this article stands. Openhanded estimates of bird kills by domesticated felines still barely comes close to the low-end figure, which would make the high-end hyperbolic at best, even factoring in ferals.

Neighbors here keep kats and they do stalk birds at our feeding stations. We've erected dog-wire (ha) rings about the base of the feeders so the ground peckers are safe.

Their kats can scale these little fences but they spook the birds before they can catch them.

Acknowledge how sickening it is the few times I've seen the kats score one of our birds, but if you can accept statistics from an anecdotal source, we've killed far more birds
here than any of the area kats--with salmonella by not keeping our feeders antiseptic.

Posted by: bando shamaly | 02 Feb 2013 23:45:15

yelling won't change the facts

As an amerikan wildlife biologist bater, I can assure you shooting pellets into anything in this borough would land you in prison.

Which hiatus would give you pause to reflect on what the science of statistics represents and how easily those not versed in it can be manipulated.

A low-to-high-end estimate that varies by nearly 300% is not statistics but guesswork.

So rounding up the best approximation of the # of domestic felines in amerika to an easy 100 million, even if every one of these killed ten birds a day, that would still account for just over half of this so-called study's low-end.

That can only mean that to validate this so-called study, there would have to be about 300 million additional feral cats--and each of them would also have to kill ten birds a day.

Nearly 400 million felines each killing ten birds a day?

Yeah right.

Whether pitched to the bird-lover or the kat-despiser, emotions are what this survey is about, not science. No reputable scientist would conscience these sweeping generalizations based on such inconclusive reportage.

Posted by: bando shamaly | 02 Feb 2013 22:45:41

What proof can possibly convince?

The Smithsonian Conservation Biology Institute and the US Parks and Wildlife serevice are out to get your poor little pussycat? Get real! A. Polden remarks that studies done when fledgelings are about give higher results! Studies confined to Antarctica would exonerate cats completely. Keeping pet cats in at night is fine - the study, however says 69% of wildbird predation is from unowned cats. No one is advocating cruelty, just an honest reappraisal of the situation by selfish owners and sentimental animal "lovers".

Posted by: Dermot McCabe | 02 Feb 2013 11:56:56

What proof can possibly convince?

Posted by: Dermot McCabe | 02 Feb 2013 11:45:39

Robert King

I am a Wildlife Biologist and all Wildlife Biologists have known for decades that in suburban America the domestic cat is the most lethal predator to our small wild species.

In America at least, the domestic cat is the greatest predator to our nesting passerine birds. There is no doubt about it.


I feed birds a lot at my house in Maine. There is a cat in the neighborhood that will not come around when it sees me. Why? Because it knows that I have filled its ass with pellets before. And I would do the same to you damn cat. Cat's should be kept inside. It is that simple.

Now if you are one of those who are such a cat lover that you simply refute these truths.......then I do not want to hear from your ass. I am glad that these studies are beginning to be forced onto the public. Accept it. It is the truth.

Posted by: Robert King | 02 Feb 2013 09:24:28

not science but cheap rhetoric

Let's forget there's no such word as "shamely" and stick to the stats quoted in the article: 1.4 to 3.7 billion kills.

Day one of any statistics class we learn to beware the gee-whizz graph. This is stereotypic gee-whizz strategy, not even remotely scientific but plainly laid down like an emotional land mine for the sophomoric--or felineophobic--candidate to tread on.

Posted by: bando shamaly | 02 Feb 2013 05:43:40

Poor interpretation

I know from Cats Protection's response to similar 'surveys' in England that much of the data is misleading. In many cases much depends on the time of year that such studies are made. Obviously if they are done when fledglings are first out of the nest, the figures are likely to be higher, as the baby birds are not 'street-wise', but frequently details of when the surveys were made is not given, and as Louise says data is extrapolated over a wider area, even when this is totally inappropriate.
If people kept their cats in at night much of the problem would be solved. The greatest danger to birds and other animals is during the periods of dawn and dusk.

Posted by: Andrea Polden | 01 Feb 2013 23:11:19

The end of my previous post

Posted by: Louise Holton | 01 Feb 2013 18:21:56


Every few years someone publishes an article about how many birds re killed of eaten by feral cats wmf an environmental or animal welfare organisation makes dig issue of it I am a lifetime environmentalist, deeply involved ib animal welfare and a biologist working in the fields of wild animal population dynamics and animal welfare. Those articles I have seen over 5o years are universally worthless from the point of view of ecology and policy; they never attempt to put hig numbers into meaningful context THey merely serve - as often intended to create an emotional and irrational response to serve some other purpose. Sidney Holt

Posted by: Sidney Holt | 01 Feb 2013 14:42:59

Let's support nonlethal control.

For the past 15 years the American Bird Conservancy has been waging war on cats. They have been spreading deliberate myths and misinterpretations about feral cats and wildlife predation, as well as Zoonotic diseases. They use science that exaggerates the data; they then extrapolate the data from small studies across states and even countries. The Temple/ Wisconsin study was in a rural area and the figures were extrapolated across the state. The Churcher study of 70 cats in a rural area brought about an outcry that cats were killing 100 million birds and small mammals in Britain each year.
Roger Tabor, British naturalist and biologist, says of the Churcher study:

Posted by: Louise Holton | 01 Feb 2013 14:24:30

Th trying to "outlaw" nonlethal cat control.

For the past 15 years the American Bird Conservancy has been waging war on cats. They have been spreading deliberate myths and misinterpretations about feral cats and wildlife predation, as well as Zoonotic diseases. They use science that exaggerates the data; they then extrapolate the data from small studies across states and even countries. The Temple/ Wisconsin study was in a rural area and the figures were extrapolated across the state. The Churcher study of 70 cats in a rural area brought about an outcry that cats were killing 100 million birds and small mammals in Britain each year.
Roger Tabor, British naturalist and biologist, says of the Churcher study:

Posted by: Louise Holton | 01 Feb 2013 14:22:18

Cats and Dogs

My cats have a large cage that I put up in the garden and they can enter the house at any time. Both of them watch the birds from their cage which feed in the garden and are used to the cats. My neighbour on one side takes his dogs out walking otherwise they are kept on his premises - if he goes on holiday we look after them. I have lost three cats due to drivers going faster than 30 mph in the limit and early mornings when they think nothing is around. Another neighbours dog used to come in my garden so I cut my hedge down and put a fence up. I love walking and like some of my friends have been befriended or even attacked by dogs - usually young and playful - sometimes wet and muddy - which have jumped up and it's been my fault for being there. The common denominator is there are too many of us and we are creating an imbalance - now finding it difficult to get on with ourselves and the rest of the animal kingdom suffers as well.

Posted by: Keith Capon | 01 Feb 2013 14:03:58

Face the facts!

It is very difficult to accurately know how many feral cats there are, and thus the wide spread estimate that bando shamaly noted. Cat science deniers will use anything to deny the problem. Maybe we don't know within 300%, but the lower number is still an ecological disaster. The scientists working on this are top professionals, and report what can be reported. To call this sensationalism is to not recognize the importance of this research, and is a typical chant of the cat lovers that can not face the facts.

Posted by: Douglas Trent | 01 Feb 2013 13:39:25

Suspicious figures

Does anyone know how many domestic cats there are in the US? I would assume its in the tens of millions. Assuming its 50million, which I wold say is generous, this would mean each cat kills an average of 6 animals per week. Seems like a bit much!

Posted by: Caleb | 01 Feb 2013 13:21:11

don't be fooled by this so-called study

No one would deny domestic cats are avid predators--but any first-quarter statistics student would dismiss this as bad science.

To give an estimate of between 1.4 and 3.7 billion kills is laughable. That's over a 300% difference. Who could possibly believe a figure with such a huge discrepancy to be accurate?

To use such obviously flawed and exaggerated data to stir up an emotional reaction against cats is the worst kind of sensationalism.

Posted by: bando shamaly | 31 Jan 2013 08:09:43

cats killers

ive never worked out any use for domestic cats ! they are called companion animals, but spend most of the time away from home. especially at night. when a companion might be handy ? put collars on them all, neuter the queens, and keep them indoors at night. license them and dogs as well actually. then maybe we wouldnt have so many of them fouling the worlds gardens ( including mine "" )

Posted by: dee donworth | 30 Jan 2013 20:40:25

To post a comment you must be logged in.

New user? Register here


Click join and we will email you with your password. You can then sign on and join the discussions right away.