January 29, 2013
Feral Cats Kill Billions of Small Critters Each Year
A feral cat, just trying to get by. Photo: Topsynette
There are so many ways for a little bird or squirrel to die these days–they can be squished by cars, splattered into buildings, run over by bulldozers, poisoned or even shot. But if you have ever had to clean up a mangled “present” left on your doorstep by a kitty, you’ll know that little creatures can also be killed by pets.
Cats in particular have earned a nasty reputation for themselves as blood thirsty killers of wildlife. They have been named among the top 100 worst invasive species (PDF) in the world. Cats have also earned credit for countless island extinctions. Arriving onto the virgin specks of land alongside sailors, the naive native fauna didn’t stand a chance against these clever, efficient killers. All said, cats claim 14 percent of modern bird, amphibian and mammal island extinctions. But what about the mainland?
A recent study aimed to find out just that. Now the stats are in, and it’s much worse than we thought. But before bird lovers rush to declaw pets, the study’s scientists also found that feral cats and strays–not house cats–are responsible for the majority of the killings.
To arrive at the new findings, researchers from the Smithsonian’s Migratory Bird Center and the U.S. Fish and Wildlife Center assembled a systematic review of every U.S.-based cat predation study known in the scientific literature (excluding Hawaii and Alaska). Based on figures the authors verified as scientifically rigorous, they statistically quantified the total bird and small mammal mortality estimate caused by cats, further breaking the categories down into domestic versus unowned cats, that latter of which the authors define as barnyard kitties, strays that receive food from kind humans and cats that are completely wild.
Their results paint a grim picture for wildlife. In a paper published today in Nature Communications, they write that between 1.4 to 3.7 billion birds lose their lives to cats each year in the United States. Around 33 percent of the birds killed are non-native species (read: unwelcome). Even more startlingly, between 6.9 to 20.7 billion small mammals succumb to the predators. In urban areas, most of the mammals were pesky rats and mice, though rabbit, squirrel, shrew and vole carcasses turned up in rural and suburban locations. Just under 70 percent of those deaths, the authors calculate, occur at the paws of unowned cats, a number about three times the amount domesticated kitties slay.
Cats may also be impacting reptile and amphibian populations, although calculating those figures remains difficult due to a lack of studies. Based upon data taken from Europe, Australia and New Zealand and extrapolated to fit the United States, the authors think that between 258 to 822 million reptiles and 95 to 299 million amphibians may die by cat each year nationwide, although additional research would be needed to verify those extrapolations.
These estimates, especially for birds, far exceed any previous figures for cat killings, they write, and also exceed all other direct sources of anthropogenic bird deaths, such as cars, buildings and communication towers.
The authors conclude:
The magnitude of wildlife mortality caused by cats that we report here far exceeds all prior estimates. Available evidence suggests that mortality from cat predation is likely to be substantial in all parts of the world where free-ranging cats occur.
Our estimates should alert policy makers and the general public about the large magnitude of wildlife mortality caused by free-ranging cats.
Although our results suggest that owned cats have relatively less impact than un-owned cats, owned cats still cause substantial wildlife mortality; simple solutions to reduce mortality caused by pets, such as limiting or preventing outdoor access, should be pursued.
The authors write that trap-neuter/spay-return programs–or those in which feral cats are caught, “fixed,” and released back into the wild unharmed–are undertaken throughout North American and are carried out largely without consideration towards to native animals and without widespread public knowledge. While cat lovers claim that these methods reduce wildlife mortality by humanely limiting the growth of feral colonies, the authors point out that the scientific literature does not support this assumption. Therefore, such colonies should be a “wildlife management priority,” they write. They don’t come out and say it but the implication is that feral cat colonies should be exterminated.
But feral cats, some animal rights advocates argue, are simply trying to eke out a living in a tough, unloving world. As the Humane Society explains, simply removing the cats may not be the most efficient means of solving the problem because cats that are inevitably left behind repopulate the colony, surrounding colonies may move in to replace the old and “the ongoing abandonment of unaltered pet cats…can also repopulate a vacated territory.” Feral cats, after all, are the “offspring of lost or abandoned pet cats or other feral cats who are not spayed or neutered.” Targeting irresponsible humans may provide a different solution, although spay/neuter laws are controversial.
In Washington D.C. alone, for example, there are more than 300 known feral cat colonies. Wildlife are victims of this problem, but feral cats are too as conditions for survival are tough. And as with so many other environmental banes, the root of the problem neatly traces back to a single source: humans. As the authors write in their paper, feral cats are the single greatest source of anthropogenic (human-driven) mortality for U.S. birds and mammals.
Incidentally, the Humane Society will host World Spay Day on February 26. Find an event for your furry friend to attend, or even host a spaying party yourself.
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Nice to see that smithsonianmag.com allows and posts death-threats against humans from the oh-so-typical sociopathic and psychopathic cat-lickers, but you won’t post my viable and humane solution for cats — one that works 100% too. If shooting cats is not a humane solution, then you must outlaw the issuing of hunting licenses in every state in every country. Cats are, after all, just another animal.
(Don’t bother deleting the cat-lickers’ death-threats, I love to collect them and archive them all, locally and at an online source. It not only shows the world for cat-lickers being the true sociopaths and psychopaths that they are, but … I know an agency that is very interested in my collection of them. :-) )
The law in the USA is that it is perfectly legal to destroy any animal, someone’s pet or not, that is threatening the health, well-being, and safety of yourself, your family, your animals, or even your property. Also true even in most densely populated cities, firearms laws permitting, if not then 700-1200fps air-rifles are commonly used. The only animals exempt from you taking immediate action, legally, are those listed on endangered or threatened species lists, and any bird species under protection of MBTA (the Migratory Bird Treaty Act). Even then variances can be given should there be sufficient problem but this requires further study by authorities. Since cats are listed in the TOP 100 WORST invasive species of the world in the “Global Invasive Species Database” ( http://www.issg.org/database/species/ecology.asp?si=24&fr=1&sts=sss ), this means they have no protection whatsoever from being shot on sight, they are not on any protected species list anywhere in the world. Quite the opposite as a matter of fact. (This is precisely how I managed to clear out every last one of hundreds of these invasive species vermin cats from my own lands. On the sound advice of the sheriff. Even he found that trying to reason with and warn the cat-lovers did no good. But shooting every last cat finally worked! My lands have been 100% cat-free for 3 years now, for less than the price of a couple cups of coffee for the ammo.)
Shoot to maim is punishable under the laws that define animal-cruelty (these are the ONLY cases that cat-lovers cite to try to manipulate and scare everyone from shooting their only favorite animal). But shoot to kill is a perfectly legal way to humanely destroy an animal. The same laws and principles that apply to methods of humanely hunting animals also applies to cats. (Hint: outfit your rifle with a good scope and laser-sight, inexpensive on ebay. This will ensure a totally humane, instant, and LEGAL kill each and every time. Though use a fatal chest-shot, a head-shot is not always a sure thing.) Unlike cat-lovers’ psychotic beliefs, the reality is that a cat is just another animal. It’s NOT their baby, their child, their offspring. Even if they do view their cats that way, letting them roam free is no less criminally irresponsible than them telling their child to go play in the freeway and then blaming the cars for their child’s death. If they let their cat roam free, NO MATTER HOW IT DIES, that is THEIR fault and they can be charged with all laws that clearly define animal-neglect, animal-abandonment, and animal-endangerment. Not to mention being in direct violation of all international invasive species laws in existence.
In fact, here’s a publication from a study done by the University of Nebraska on the best ways to HUMANELY deal with a feral-cat problem wherever you live. This documentation INCLUDES the best firearms, ammo, and air-rifles required to HUMANELY destroy cats. deenawinter.files.wordpress.com/2010/12/ec1781.pdf
Besides, what difference does it make if the cat gets shot or ran over by a car, attacked by another cat or animal, drowned, or poisoned by plants animals or chemicals (inexpensive 1-adult-strength generic acetaminophen pain-relievers gaining in popularity, for being so species specific, far far safer than antifreeze and rat-poisons that cat-lovers have forced everyone else into using lately). The result is the same. The cause is the same — the fault of the criminally irresponsible pet-owner that let their invasive species pet roam free. They’ve already proved that their animal is 100% expendable. You can either destroy their cat for them humanely, or let their lack of care cause it to inevitably die inhumanely. They don’t care one bit how their cat might cruelly suffer to death if they let it roam free. Humanely destroy their cat for them before that can happen. A well aimed bullet is the MOST humane death that ANY stray or feral cat can ever look forward to. Any other death that they WILL eventually face is all inhumanely downhill from there.
You might also enjoy knowing …
If you advocate for cats as rodent-control on farms and ranches you’ve already doomed them to being destroyed by drowning or shooting when it becomes a financial liability more than any asset. Ranchers and farmers worldwide are fully aware that cats’ Toxoplasma gondii parasite can cause the very same birth defects (hydrocephaly and microcephaly), still-births, and miscarriages in their livestock and important wildlife as it can in pregnant women. Consequently, this is also how this cats’ brain-parasite gets into your meats and onto your dinner-tables, from herbivores ingesting this cat-parasites’ oocysts in the soils, transferred to the plants and grains that they eat. Not even washing your hands in bleach will destroy this parasites’ oocysts if you have contracted it from your garden or yard that a cat has defecated in.
This is why any cats are ROUTINELY destroyed around gestating livestock and wildlife-management areas in the most efficient, humane, and least-expensive method available. Common rural practice everywhere. The risk of financial loss from dead livestock and important native wildlife from an invasive-species cat is far too great to do otherwise. This cats’ parasite is now even killing off rare marine-mammals along all coastal regions from run-off containing this cat-parasites’ oocysts.
The next time you bite into that whole-grain veggie-muffin or McBurger, you need to just envision biting down on a shot-dead or drowned kitten or cat. For that’s precisely how that food supply got to your mouth — whether you want to face up to it or not. It’s not going to change reality no matter how much you twist your mind away from the truth of your world.
If you want to blame someone for the drowning and shooting of cats, you need to prosecute yourself — every time you eat.
Woodsman,
Somehow, the inappropriate comment you refer to was approved when it should not have been. I have removed it. I’m terribly sorry for this!
Mohi Kumar
Surprising Science Blog Editor
Human beings are by far the most dangerous, destructive animals on this planet. All one need as an example is this article. I wish I had a subscription to cancel, but will encourage as many as I can to do so, via the Net.
I have a friend who has a farm. She had barn cats Until they all passed away and then she began using pesticides to control the rodents that were overtaking her barn. Since she began using the pesticides, she noticed that she no longer sees barn owls, hawks and other birds of prey, After doing some research, she discovered that they were more than likely disappearing because of secondary poisoning from the pesticides. She was heartbroken to discover that she may be responsible for poisoning a lot more than the rodents. She plans on getting more cats (spayed and neutered, is course) and getting rid of the pesticides. And in argument that cats carry diseases like toxo which are hazardous to humans, don’t forget that they also kill mice which carry fleas that cause the plague and hantavirus, so that argument is really null and void. I believe that pollution, pesticides and deforestation have a much greater effect on the environment than cats.
Tammy, how about CAT TRANSMITTED FATAL PNEUMONIC PLAGUE
Cat-Transmitted PLAGUE:
http://www.ncbi.nlm.nih.gov/pubmed/8059908
http://www.pagosasun.com/archives/2011/07July/072811/webplague.html
http://www.nydailynews.com/life-style/health/oregon-man-suffering-plague-critical-condition-article-1.1094782
http://www.daily-times.com/ci_20849462/health-department-said-taos-cat-has-plague
Totally disproving that oft-spewed myth that cats in Europe could have prevented the plague. No rats nor fleas even required. Cats themselves carry and transmit the plague all on their own.
Google for: “Cat-transmitted fatal pneumonic plague”, or Oregon man suffering plague, or Taos cats plague, or Yellowstone feral cats plague, or hundreds of others in the last decade. Yes, people have been dying from cat-transmitted plague in the USA. Not too bright, are you. But then what cat-lover is?
Totally disproving that oft-spewed myth that cats in Europe could have prevented the plague. No rats nor fleas even required. Cats themselves carry and transmit the plague all on their own.
These are just the diseases YOUR CATS have been spreading to humans, not counting the ones they spread to all wildlife. THERE ARE NO VACCINES against many of these, and are in-fact listed as bio-terrorism agents. They include: Campylobacter Infection, Cat Scratch Disease, Coxiella burnetti Infection (Q fever), Cryptosporidium Infection, Dipylidium Infection (tapeworm), Hookworm Infection, Leptospira Infection, Giardia, Plague (no rats nor fleas even required, cats themselves carry and spread it all on their own once infected), Rabies, Ringworm, Salmonella Infection, Toxocara Infection, Toxoplasma. [Centers for Disease Control, July 2010] Sarcosporidiosis, Flea-borne Typhus, Tularemia, and Rat-Bite Fever can now also be added to that list.
Especially dangerous today since cats attract rodents right to them with their Toxoplasma gondii parasite that hijacks the minds of rodents.
Its strange life cycle is meant to infect rodents. Any rodents infected with it lose their fear of cats and are actually attracted to cat urine.
Google for: parasite-hijacks-the-mind-of-its-host
Cats attract rodents to your home with their whole slew of diseases. If you want rodents in your home keep cats outside of it to attract diseased rodents to your home and family.
If the cats infect all rodents with their T. gondii parasite everywhere that cats defecate you’ll see a plague the likes of which have never existed before. Especially when you breed super-strains of plague with your overuse and irresponsible use of antibiotics.
The time has come to destroy them all whenever spotted away from supervised confinement. There’s no other solution. We have nobody but cat-lickers to thank for this disaster. All stray-cats, the very source of all feral-cats, must be destroyed too or you’ll never stop the feral-cat disaster that exists on every continent today.
And here I thought the Smithsonian was a scientific, intelligent, fact-based institution dedicated to good sound research, um-biased reporting and education.
Guess I was wrong.
Turns out they’re just as susceptible to bias, pay-offs, and all-around nonsensical crap as everyone else. My faith in humanity is now knocked down another peg.
If this comment is not approved I will know for certain I am right.
P.s. The “research” for this article is funded in part by the U.S. FISH AND WILDLIFE SERVICE. What do they want? More game for hunters to shoot.
Let’s take this into consideration when reading.
Complete claptrap. I will not read anymore Smithsonian materials nor will I ever support this place again. This is bad science, and totally slanted. No eveidence, no fact and data given – thus we can only conclude what the cat hater bird lover crazy wants. Perhaps they (the bird lover crazies) should focus on the man made threats to song birds – population, pollution, habitat loss, pesticides and the like. Unfortunately they are using this as scince and feeding it to kids and others who don’t know enough about science to be descriminating in their consumption of “facts”. And yes, a large portion of those “mammals” killed are rodents that damage crops, carry fleas and ticks and are disease vectors(hum, Lyme’s disease, Hanta virus, bubonic plague, babiosis or bartonella ring a bell, anyone??)
We have a creek in the apartment complex suburb where I live, with Mallard ducks, mourning doves and all sorts of songbirds. There were a few feral cats that didn’t really cause any problem. Then a crazy cat fanatic moved in who started leaving deli trays on the parking lot, actually left old sofa cushions in the wooded area behind the apartments so the cats would have a place to lounge, and left all sorts of food all over the proerty. Thanks to this nutjob, we now have a cat army of aggressive predatory ferals roaming all over the property and we cannot get any help with this. They killed all of the early season ducklings last spring, plus a number of adults, we found dead decapitated songbirds all over the place, we no longer have any doves. This crazy cat person volunteers for a cat rescue group but lies about doing TNR. We are trying to work with the group’s head person, now, to get this mess under control, but frankly, I have my doubts. My experience with cat people is, unfortunately, all they care about are cats, they have no regard for other animals and I think they have control issues and this is how they act out.Like all animal problems, it is caused by humans. But the animals pay the price.
I know there is some claim that the Smithsonian study is tainted but I have to say, after seeing what cats did here – and I have lived in my development for 40 years without any problem until this cat situation got out of hand – I believe they are 100% on target.
The feral cat problem is completely out of control and TNR is not working.
As usuall it’s more the humans fault that the infestation occurs. I am a cat person and our cats stay indoors exclusively. The feral cat issue is solely due to the irresponsible humans who turn them loose instead of taking the resposibility of taking care of their pets and if they didn’t want them, don’t take them in in the first place. If activists are going to take pity on feral cats they need to be responsible about it as well and try to find them homes or get them neutered or spayed. The other side of this debate also needs to realize that cats have been wild for centuries in areas of the world like Egypt and India without devastating the small critter community. Cats provide a valuable service to us all by keeping the mice and rats to a manageable level. Maybe instead of killing the feral cats we should trap, neuter , then ship them to The big cities to feed on the rats In the sewers and warehouses… I have helped out local cat coalitions and have found homes for a few and taken in others. In conclusion, we need to take Bob Barker’s advise and please spay and neuter your pets!!!
I’m a bit puzzled about the whole TNR thing. Pro-TNR people will say it is morally wrong to euthanize a feral cat instead of fixing it and letting it go, and many will send death threats to anti-TNR people. However, shelters are euthanizing healthy friendly cats every day, whether it be due to lack of space or simply because it is easier to kill an animal than put in the effort to start a fostering program or keep the shelter open for longer hours to promote more adoptions.
How come pro-TNR people aren’t sending death threats to shelter workers? Why is it okay to kill a friendly cat, but not an unfriendly one? Why don’t shelter cats deserve to be let loose?
If these were feral ball pythons (which are completely harmless to humans) we were talking about instead of cats, there would be no argument. Even reptile owners are fine with removing invasive reptile species. It’s like there is something about cats that makes people act irrational.
This article isn’t surprising science it’s junk science.
You do know Coyotes kill birds,foxes,rabbits,cats,small to medium dogs,deer,chickens,livestock ect… Coyotes are everywhere they are large they eat a lot more that a cat. They carry deceases especially deceases that effect dogs. They jump fences in suburban yards to grab pets. Why do we always have to blame cats when there are many other larger predators out there. Don’t forget Hawks eat small mammals and yes a lot of birds. There’s a long list of bird eaters, why only zero in on cats? Maybe because you see it where as the other bird eating predators are more on the sly I don’t know, but you should maybe you should do some research on other bird eaters once in the while.
HaHa these comments are so predictable & laughable. Most of these fools including woodsman are just bird lovers in disguise. they advocate killing all stray & feral cats to further the repopulation of native birds. The fact of the matter is they would love to completely rid the world of all Cats domestic & otherwise because they love birds, end of story. ROFL
I am outraged and sickened by the vicious, hateful message of this article. I am nearly unable to compose a thought. But I can say that focusing on cats as killers because they need to eat is quite heartless and tunnel-visioned. I believe that there are a few more animals in this world that have to kill to eat besides cats, and dogs are “killers” as well. If they aren’t out chasing squirrels and such other animal, they are eating dog food made from animals who were raised in unspeakable conditions and killed by cruel methods. I daresay a dog will kill a bird also, given half a chance. Even though I love cats and find their company wonderful, I respect the right of others to delight in birds or other animals. But I also expect my right to love my pets to be tolerated, if not appreciated. The love for a pet can be a very deep and serious relationship, which should be respected. I am absolutely stunned that The Smithsonian would publish such malicious tripe. My regard for you has just plummeted, as well as my regard for the Audubon Society.
S. O. Rooney
Colour me not surprised, to see this coming from the institution that harboured Nico Dauphine as a ‘researcher’ into the impact of cats on wildlife, until the said ‘researcher’ was convicted of animal cruelty for attempting to poison cats.
Even then Dauphine was not dismissed, but was allowed to resign having published a number of papers on the topic.
Smithsonian has nil credibility on this issue.
http://opinion.latimes.com/opinionla/2011/11/a-dc-bird-researcher-is-convicted-of-trying-to-poison-cats.html
That said, I do not expect this comment to be published. Too embarrassing, you see, for the Smithsonian.
Cats are predators. Of course they will eat prey animals. And they are a potentially invasive species, because they’re tough and will eat just about anything that can’t eat them first. Overpopulation of pet species is a rampant issue in the US, specifically with regard to dogs and cats, because people don’t spay/neuter. I don’t agree with the idea of exterminating entire populations, but I otherwise fail to see what everyone’s issue is. Most of this article is just common sense facts repeated with large numbers. Of course cats eat birds and small mammals in an area. Sure, Woodsman is coming off as a jerk, but people will be people, and though he is coming off as a jerk, he may be right. If spaying and neutering isn’t affecting a population and it’s growing out of control, killing the population off may be the only option available. I’m a cat lover with two rescues at home, and that doesn’t change the facts of a situation.
So far my neutered ferals have eaten several mice, one squirrel, and many crickets and similiarly sized insects as well as the diet I provide. So far the owls, eagles, and hawks have killed 4 of my ferals. The birds are winning. Birds have more defensive equipment than cats. I have little sympathy for the bird people in this little war. Individual have rights too not just broader populations. As in any war, we have to choose sides. Rationality has nothing to do with it. “Reason” has lead us to disaster just as efficiently as emotion.