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April 27, 2015

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House cats: The invasive species

There is an invasive species in the United States responsible for the deaths of an estimated 14.7 billion birds and mammals each year. If that’s not shocking enough, consider this: There’s a good chance that one of these invaders is living in your house.

The next in a long line of scientific studies documenting the impact of outdoor cats on our natural environment has just been released, bringing national attention again to the issue. This study was published in Nature Communications and authored by scientists from the Smithsonian Conservation Biology Institute and U.S. Fish and Wildlife Service.

Another study, published in the peer-reviewed public health journal Zoonoses and Public Health, found that free-roaming cats also pose a threat from “serious public health diseases” to humans, domestic animals and wildlife. The study came from scientists at the University of Tennessee and a retired scientist from the California Department of Fish and Game. Among the key findings of that paper:

• Free-roaming cats are an important source of animal-transmitted, serious diseases such as rabies, toxoplasmosis and plague;

• Free-roaming cats account for the most cases of human rabies exposure among domestic animals, and are the source for one-third of rabies post-exposure treatments in the United States (because of inconsistent incident reporting, that number is likely an underestimate of the actual cases of rabies exposure);

• Trap, neuter and release programs may lead to increased, uninoculated populations of cats that can serve as a source of transmittable, serious diseases.

The study also noted that since 1988, rabies has been detected more frequently in cats than in dogs; in 2008, the number of cats detected with rabies was four times higher than dogs. In 2010, rabies cases declined for all domestic animals except cats.

A different study on the effects of urbanization on wildlife tracked the early lives of gray catbirds in three areas of Washington, D.C.’s suburbs. It found that outdoor cats were the top source of known predation on the young birds.

On top of that, a University of Georgia study announced this past summer found that outdoor cats that killed did so once every 17 hours. The study authors attached small video cameras to 60 outdoor domestic cats in Athens, Ga., and recorded their outdoor activities during all four seasons.

These recent studies and dozens more lay to rest any argument as to whether outdoor cats inflict great damage on native wildlife. They demand from the public a serious look at how we can protect biodiversity from this introduced predator.

The only sure way to protect wildlife, cats and people is for domestic cats to be permanently removed from the outdoor environment. Trap-neuter-release programs that perpetuate the slaughter of wildlife and encourage the dumping of unwanted cats is a failed strategy. It can no longer be tolerated.

Local governments need to act swiftly and decisively to gather the 30 million to 80 million unowned cats, aggressively seek adoptions, and establish sanctuaries for or euthanize those cats that are not adoptable. Furthermore, pet cats should be spayed/neutered and kept indoors. For their own safety, owned cats need to be licensed and microchipped.

Any notion that cats need “outdoor time” flies in the face of reality. Outdoor cats live about one-third as long as indoor cats, owing to their exposure to a variety of diseases, parasites and toxins, as well as to their predictable run-ins with dogs, other cats, foxes, coyotes, vehicles and, of course, abusive people.

Only through proper identification can lost cats be consistently returned to their homes, and no owners need worry about accidental adoption or euthanasia of their beloved companion. It is also time to treat cat owners as we treat dog owners by enforcing anti-abandonment laws and requiring leashes or enclosures for cats outdoors. Such an approach is better for cats, better for birds and better for people.

George Fenwick, president of the American Bird Conservancy, received a Ph.D. in pathobiology at the Johns Hopkins University, studying the effects of alien species on native birds. He wrote this for the Baltimore Sun.

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  1. The article is scholarly and erudite. But lacks the common sense reality that cats are and always will be outdoor/indoor inhabitants. They roam and prey. It's what distinguishes them as a domesticated species from dogs.


  2. There's an old saying that says you can own a dog, but cats own you. I always observed that, once outdoors, you couldn't tell the difference between a feral and a "domesticated" cat.

  3. Although I love cats, well, all our animal friends, there is a point where I also draw the line and look for pet owners to be responsible about their pets, any of them. In the case of feral cats, the writer, George Fenwick, is correct in his observations and analysis.

    Here in Las Vegas, and with hundreds of thousands of people losing their homes during this financial crisis, at least the same amount of domestic cats had been left behind, uncared for, while their owners moved on. As a consequence, these cats have freely reproduced, and are all over the place.

    Some well intentioned folks at my school, leave food and water for such animals, not realizing these adorable cats defecate in the gravel ladened dirt, leaving piles that students invariably step on and track throughout the school campus. Also, these cats go underneath the portables to do their business. Then there is the issue of cats having sex around the students (try being a teacher having to deal with that hot potato!) From time to time, the playground field is littered with dead bird corpses, grossing out young children. We tried to curtail the population with the local organization that traps, vacinates, neuters, return release program, and still, the problem exists.

    Because a forth of my neighborhood has foreclosures, there are a plethera of roaming cats...everywhere. "Invasive species" is putting it mildly from my perspective.

    Blessings and Peace,

  4. Hunting licenses for cats-yeh !

  5. There are at least a dozen feral cats that live in the ravines surrounding my apartment complex. Some are as big as small dogs!! And by my observations, they are content to live off the wildlife that is available to them (and there is plenty for them to choose from) instead of eating the cat food I sometimes I leave out. Also, it would be very hard to "trap" any of these cats to take to the shelter to be neutered. And yes, some have had kittens and unfortunately, most likely some were dinner for the deer and hawks and God knows what else that also live in the ravines. I'm a huge cat lover and it worries me when the weather is bad, ie cold, snowy. I always want to take them all in - or at least build some kind of shelter for them but let's face - it's nature. Feral cats can take care of themselves in ways we know nothing about. Once the weather clears and warms up - they'll all be out there hunting for food, no worse from the wear and tear of snow and cold!!

  6. "Common sense reality" is not evidence -- or even a reasoned argument. The author has cited several studies in support of his proposition that domesticated cats can, and should, enjoy their lives indoors. If you have a contrary view, we'd like to hear it -- and your evidence to support that view.

  7. I must admit to being a cat lover. The writer does make a valid point in that it is a shame that cats kill so many birds, mice and rats. The high cost of veterinary care is certainly a big impediment to keeping the cat population, feral and domesticated, under control. So many people simply don't have the spare funds to get their pets neutered, so they either let them roam intact or dump them.
    However, the writer's solution of forcing cats to remain indoors seems both unkind and unnatural to me.
    Having said that, perhaps his line of reasoning could be usefully employed to keep hunters and their guns indoors as well. After all, hunters are also responsible for extensive slaughter of innocent wildlife. Just a thought!

    Donald W. Desaulniers

  8. "...some have had kittens and unfortunately, most likely some were dinner for the deer and hawks and God knows what else that also live in the ravines."

    Det__Munch -- deer don't eat cats or any other meat. Are you really that ignorant?

    Where I live we have a feral cat problem. Cayenne on the parts of my yard they use for a litter box is short term solution, but expensive. Seems the only thing they respect is the bb gun.

    "All animals are equal, but some animals are more equal than others." -- George Orwell's "Animal Farm" (1945)

  9. ""Common sense reality" is not evidence -- or even a reasoned argument." Emthree

    Statements like this prove common sense is uncommon.


  10. According to the science of physics, an erudite and scholarly discipline, bees can't fly. But somehow they do.


  11. I got to agree with killer and I rarely do , but dogs and cats are really one species of mammal which are really plastic creations bred to entertain first the rich elites. We loose many species of the order Aves frequently.

  12. <<Det__Munch -- deer don't eat cats or any other meat. Are you really that ignorant?>>

    KillerB: No I'm not ignorant, but I at least have more class than you because I wouldn't suggest you are ignorant even though some of your posts suggest otherwise.

    Besides - I'm a "city girl" - having wild life roaming 10ft off my patio is all new to me and I'm fascinated by all of it. And how the hell do I know what deer eat????

  13. <<According to the science of physics, an erudite and scholarly discipline, bees can't fly. But somehow they do>>

    And they always seem to be flying into open car windows and towards me when I'm just minding my own business!!

  14. "...I at least have more class than you..."

    Det__M -- opinions vary

    "I'm never too busy that I can't stop to enjoy someone else's suffering." -- the late, great George Carlin in "White Guys Who Shave Their Heads"

  15. "And they always seem to be flying into open car windows and towards me when I'm just minding my own business!!" Det__Munch

    It's your perfume. Bees have excellent sense of smell. ;-)


  16. I have not been able to get this column off my mind, because no one mentioned what bothered me about the column, namely the flawed support for Fenwick's drastic conclusion that local governments should spend resources to "swiftly and decisively" gather all of the homeless cats. Those that can't be placed will be euthanized. That is overkill. Of course,I do agree with his statement that we should use adoption and sanctuaries.

    He carelessly stated the "shocking" estimate of 14.7 billion birds and mammals that are killed annually by "an invasive species." This significantly differed from his referenced source (a 1/29/13 article in Nature Communications). It gave "speculative" estimates: 1.4-3.7 billion birds and 6.9-20.7 billion mammals annually.

    Also, the statement that "free-roaming cats are an important source...of rabies, toxoplasmosis, and plague" was an exaggeration. reports that people are more likely to catch toxoplasmosis from eating raw meat or gardening than from cats.

    Fenwick tried to discredit trap-neuter-return (TNR) programs, but they are part of the solution. TNR volunteers and representatives vaccinate and give medical treatment. By definition, neutering will reduce the feral cat population.

    He called TNR a "failed strategy" that "encourages the dumping of unwanted cats." I think his degradation and demonization of "an invasive species" contributes to cat dislike and neglect.

    Invasive species Homo sapiens is supposed to be the wise species. Fenwick's idea that we have to choose between cats and birds is a false dichotomy. We are smart enough to help both species.