Monday, August 29, 2011

The Problem with Feral Cats....

Feral and/or stray cats abound around our new rural home.  I'd gotten pictures of them in the woods behind our house on several occassions, but didn't realize the level of the "problem" until I put a cam along the back of our garage facing an Eastern Chipmunk (Tamias striatus) burrow.  Although I thought it was a tad too soon, I checked the camera after 24 hours to see if the angle I used was good.

I was shocked too see how many times a puddy tat passed in front of the camera during that time.  Four different individuals (mugshots below), passed the camera a total of seven times within 24 hours.





They are obviously interested in the Chipmunk burrow as well....I've gotten pics of other rodents scampering around in this spot too, so it's a kitty buffet trail.

The worst part is that I only one of these individuals is one that I've caught pictures of before.  I now believe I have observed a total of SIX different individuals slinking around the property.

The last kitty kat pictured above has been camera-trapped in several different locations near our house.  In one case, the pictures of him depicted dastardly activities (see below)!

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Some folks are shocked when I tell them that I am a wildlife conservation biologist, and that I could care less about protecting stray or feral cats...or even protecting pet cats allowed to run loose.  They seem to think that because I like "animals", I also like feral stray cats.

However, "Wildlife" and "Domestic Animals" or "Feral Domestic Animals" are very different things.  There is nothing "natural" about a feral or stray cat on the loose.  There is also nothing natural about a domestic cat that is allowed by its owners to come and go as it pleases.  They are not native wildlife.  They are an introduced exotic species. As such, in my humble opinion, they have no business loose on the landscape.

We have a number of native wild Felids in North America.  Several once had fairly extensive ranges in the US: the Bobcat (Lynx rufus) and the Cougar (Puma concolor).  The others had historic ranges that barely entered U.S. borders to the south, such as the Jaguar (Panthera onca; which once had a somewhat extensive range in the southwestern US), the Ocelot (Leopardus pardalis) and the Jaguarundi (Puma yagouaroundi).  To the north, the Canada Lynx (Lynx canadensis) had a range that once included a fair portion of the northern U.S..

Most of these wild felids have been extirpated from the U.S., or had their ranges and populations drastically decreased in the last 100 years.  The Bobcat still has a fairly extensive range compared to the other species.  The Cougar is relatively common in the west, and expanding its range eastward (although east of the Mississippi River it is still very uncommon or nonexistent).

So, we have native cats that could actually use protection or conservation. Yet some folks will immediately jump on board with protecting feral cats as fast as they will native wildlife.  There are, in fact, entire organizations devoted to stray pet advocacy, and promote the trap-neuter-release policy for feral cats.  Alot of these folks may actually get down-right angry at any mention of actively controlling feral cat populations via lethal removal.  I often hear it implied that such activities are inhumane.  They seem to prefer the trap-neuter-release method of population control.  Granted, this may result in a decrease in feral cat populations over a longer time period (at least in areas where the method is rigorously practiced and upheld), but a neutered cat still needs to eat.  Trap-neuter-release doesn't make up for the fact that these feral neutered individuals must still hunt for the remainder of their lives. 

I'm also confused about how lethal removal of feral cats is viewed as inhumane, while granting these unnatural predators free reign to eat wildlife is not.

If we must protect feral cats, why not protect all feral animals?  Where are the feral hog advocacy groups?  Why not protect invasive species of snakes?  How 'bout some pro-zebra mussel propaganda?  I'll tell you why feral cats are treated differently: they're cute and make us think of our pets (or they actually are pets).  Who can identify with a giant bristling feral hog, with tusks like bananas tearing up native vegetation?  Who can identify with an exotic snake that eats something "desirable", like a bird (or a house cat)?  Thus, decisions about which side to be on are driven by emotion.

But, I digress.....

I had originally planned to review papers that have studied the impact of feral cats preying on native wildlife in this blog post.  Yet, I've found that this just results in a powder keg of constant squabbling by folks on both sides, so I decided to drop that.

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At any length, I knew there were feral cats in the area after only two nights of camera trapping (see my previous post).  It only took another week to get pictures of them preying on wildlife.  I believe the prey in the pictures below is an Eastern Chipmunk.  We have several that run around the backyard caching food in various places.






Chipmunks are, obviously, not a rare species...but that is not the issue.  The problem is that, in less than a month, I have captured pictures of six different feral cats in the vicinity of our house.  Within the first week of us being here, I captured three cat pictures just off our back porch.  One of these was a photograph of a predation event. 

The numbers of predation events that go undetected are likely substantial.  All of these cats are going to eat somehow.

Further Reading (just a smattering from the diverse body of literature that exists on this subject).

Crooks and Soule, 1999. Mesopredator release and avifauna extinctions in a fragmented system. Nature 400:563-566.

Guttilla, G.A. and P. Stapp. 2010. Effects of sterilization on movements of feral cats at a wildlife-urban interface. Journal of Mammalogy 91:482-489.

Foley, et al. 2005. Analysis of the impact of trap-neuter-return programs on populations of feral cats. Journal of the American Veterinary Medical Association 227:1775-1781.

Hawkins, C.C., et al. 2004. Effects of house cats, being fed in parks, on California birds and rodents. Pgs. 164-170. In Shaw et al. (Eds.) Proceedings of the 4th International Urban Wildlife Symposium.

Lepczyk, C.A. et al. 2003. Landowners and cat predation across rural-to-urban landscapes. Biological Conservation 115:191-201.

Levy, J.K., et al. 2003. Evaluation of the effect of a long-term trap-neuter-return and adoption program on a free-roaming cat population. Journal of the American Veterinary Medical Association. 222:42-46.

Nogales, M. et al. 2004. A review of feral cat eradication on islands. Conservation Biology 18:310-317.

Risbey, D.A. et al. 2005. The impact of cats and foxes on the small vertebrate fauna of Heirisson Prong, Western Australia. II. A field experiment. Wildlife Research 27:223-235.

The Wildlife Society. 2011. In Focus: the impacts of free-roaming cats (multiple entries by several authors).  The Wildlife Professional 5: 50-68.

16 comments:

  1. Free-range house cats have a MUCH larger impact on the environment than most folks realize. My two dearly-beloved kitties stay indoors or visit the great outdoors on a leash (yes, a leash, if you can imagine). I bet you'd enjoy this post by my friend Murr--she shares our point of view on this, but comes at it with a wicked sense of humor: http://murrbrewster.blogspot.com/2011/05/it-came-from-cretaceous.html

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  2. Good post. Few people realize how destructive cats can be to wildlife.

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  3. Few people want to admit their cats have a HUGE impact on songbird population..it's shocking.
    Or..the impact on 500 pounds of organic soil in ones raised beds. SOMEONE out there owes me a lot of money. Grr.

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  4. I wonder if there are more feral cats in areas where there aren't so many bobcats, cougars, and coyotes. Around here, a feral cat simply cannot survive. It is killed by natural predators. I have never seen one or camera trapped one in the 12 years that I've lived here.

    You asked in my post with mountain lion photos about where I live relative to "suburbia" or a big city. The nearest "city" is Boulder, not huge, but definitely urban near its center. It's about 10 miles and 3000' vertical feet away. I live in an area where the smallest lots for houses are about 5 acres, and there are only major arteries (ha! our "major" artery is a dirt road but it connects two paved roads). There aren't networks of roads made just for houses like in suburbia. That leaves vast swaths of open land.

    My main camera trapping area is a very steep north-facing wall of a canyon. The area is very seldomly traveled by people. It looks too steep to naive people, and the locals are scared to go there due to the high density of cats and bears. So, fewer than a dozen different people per year walk on the one trail that traverses thousands of acres of hillside. As you know from my photos, many more animals, including cougars, go there regularly during the snow-free months.

    One last point of interest - all of the animals don't use that slope for travel in the winter. I'm still working on figuring out their alternative routes - but a main one seems to on the very edge of the top of the canyon wall where the snow doesn't get so deep.

    Sorry for the long comment - I thought that you might be interested in the details given your expertise. I'd love to have someone like you evaluate our area and give me tips about the significance of different geographical features. I'm learning on the fly.

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  5. Hey KB...

    I think you're correct regarding the natural predators and feral cats. In fact, the work by Crooks and Soule I reference above discusses this phenomena as it relates to feral cats in chapparal fragments out west. The natural predator in this case being the coyote. The presence of coyotes in fragments increased bird diversity because the 'yotes excluded kitty kats.

    Interestingly, we have coyotes on our property....or at least they use a portion of our property. But they are wary here and don't often seem to come near the home. Thus, the puddy tats congregate 'round here: easy food and no 'yotes, I would suspect.

    Cool stuff about your camera trapping location! It would seem logical that the critters would follow ridge tops in the winter (good spot to see and smell things...and with the wind the snow drifts should be lower, I'd think....? Also, I'll bet alot of them just follow plowed roads, especially considering that yours likely don't get alot of traffic from your description (just a guess).

    I would love a reason to come to Colorado and hike around on those mountains of yours!! Some day if my family can ever afford to take a vacation, I'll maybe come knock on your door. :)

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  6. Don't have a lot to add as you really hit the nail on the head, but thanks for this post.

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  7. I'm not shocked that you don't care about the ferals. I am saddened, but not shocked.

    There are all too many humans who, like you, wish to destroy the evidence of human failure. Humans caused the feral cats and humans would rather destroy them quickly than work to eliminate them through education on spay neuter and TNR.

    Just pathetic.

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  8. Let’s set aside the question of whether lethal control is humane or not. Can we kill our way out of the “feral cat problem”? Experience suggests we cannot.

    Consider what “successful” eradications program involve:

    On Marion Island (115 square miles in total area, barren, and uninhabited), located in the South Indian Ocean, it took 19 years to eradicate approximately 2,200 cats, using disease (feline distemper), poisoning, intensive hunting and trapping, and dogs.

    On Ascension Island (34 square miles, and a population <1,000), eradication efforts (~635 cats killed over 27 months) totaled GBP 650,000 (approximately $1.1M today).

    Being a wildlife conservation biologist, you must be familiar with these case studies. I wonder, then, what solution(s) you would propose.

    Peter J. Wolf
    http://www.voxfelina.com

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  9. Thanks for this excellent post, which further documents what The Wildife Society and 60 other conservation and scientific organizations and societies, such as Audubon, SCB, ABC, and NWF, have been saying for some time. Feral cats are bad for our native wildlife and for people. They kill millions of birds and other small animals annually and spread dangerous diseases such as toxoplasmosis to both humans and wildlife. Models have shown that capture and removal is much more effective than TNR in reducing cat numbers and many communities (e.g. Maui, San Antonio, etc.) seeing that TNR is ineffective, are having second thoughts. It is high time to keep cats indoors. By the way coyotes love to eat cats; in one study in Tucson, AZ, cats made up 40% of their diet. Many outdor cats are also killed by cars and trucks--another good reason for people to keep their precious pets indoors!

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  10. Yes, it is high time to keep pets indoors. It is also high time to spay and neuter pets.

    I notice that the only "scientific organizations" you mention are wildlife organizations. I find that rather telling. That must mean that there are no scientific types who dispute this. I find that mildly unbelievable.

    I do not dislike any of the organizations you mention and have, indeed, contributed to them. I do not go to them however for my information on feral cat control. They also are lobbyist organizations backed by many dollars from hunters, fishermen and bird watchers, some of whom have a distinct wish to hunt feral and stray cats.

    Now here's a "scientific study" idea. Do you suppose there would be any interest in how much wildlife is destroyed because we have moved into their habitat? I realize that "we" brought the feral cats with us but I would be interested in seeing a study talking about how many animals and birds have lost their habitat due to the encroachment of humans - some of whom have never had a pet.

    Interesting concept? Maybe the Audubon Society, ABC and NWF should broaden their research horizons.

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  11. Susie: This has nothing to do with "destroying evidence of human failure". Such an endeavor would be an act of futility...and anyone thinking otherwise is kidding themselves. This is about biodiversity conservation, which should transcend anything to do with humans (including covering our failures or being fond of pet cats).

    It is my opinion that it is a much greater travesty to let these exotic predators have un-controlled access to eat native fauna.

    In addition, to suggest that, because humans caused the problem in the first place means we should not attempt to correct it, is ridiculous. What would have happened if humans stood back and did nothing to correct our mistakes associated with much larger problems? We are the cause of climate change. Should we sit back and let it drive polar bears to extinction? Humans have made lots of money selling bits of tigers for folk remedies. Should we passively stand around while tigers are poached into non-existence? No.

    I would not consider this point of view to be "pathetic". What I DO consider pathetic is deeming it acceptable to allow this exotic species to wreak havoc on native wildlife. I also consider it pathetic that people can be so selfish as to only care about one type of domestic animal that they are fond of...and at the expense of entire communities of native species.

    Pete, I don't think there are any great solutions to this issue. However, I am of the mind that spending several million dollars to eliminate this threat is worth the money. Millions of dollars are already spent on conservation initiatives. There is a large body of literature supporting the hypothesis that feral/stray cats have a significantly negative impact on native wildlife....thus this is an important conservation initiative.

    Furthermore, on both Marion and Ascension island the methods employed were successful (i.e., to my knowledge feral cats have been eradicated from both). Therefore, spending the money was justified and the outcome was successful. Using resources to control this issue should be no different than using them to control invasive plants world wide, sea lampreys in the Great Lakes, Nile Perch in lake Victoria, and etc..

    A review of cat eradication on islands can be found here:

    Nogales, M. et al. 2004. A review of feral cat eradication on islands. Conservation Biology 18: 310-319.

    I understand that some folks may not agree with me on this. That's fine. Susie, your being required to resort to insults, however, is hardly justified and shows incredible insecurity regarding your stance on the issue. It's fine to like pet cats. Yet in my opinion, once they are outside, they are no longer pets. Any other pets that has destructive tendencies is not allowed to roam free. I have a dog. Should I let it run loose in my neighborhood because I like him? No. I used to have a pet rattlesnake that I used for educational purposes. Did I allow it to roam free because I liked it? No. The same should hold true for cat owners.

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  12. Well, your last post is probably the most damning for your reputability.

    Your comment: "I notice that the only "scientific organizations" you mention are wildlife organizations. I find that rather telling. That must mean that there are no scientific types who dispute this. I find that mildly unbelievable.

    I do not dislike any of the organizations you mention and have, indeed, contributed to them. I do not go to them however for my information on feral cat control. They also are lobbyist organizations backed by many dollars from hunters, fishermen and bird watchers, some of whom have a distinct wish to hunt feral and stray cats."

    My response: none of the organizations mentioned are "lobbyist" organizations. They are also rarely backed by individuals with a sole goal of hunting and fishing, although I'm sure there are many members that hunt and fish, these organizations are devoted biodiversity conservation...not outdoor sports. While organizations like the Audubon society does have many bird watchers in their membership, the majority of the members of organizations like The Wildlife Society are ecologists and biologists who are trying to determine the level of threat (which all evidence suggests is substantial) and how to correct it. Trust me...if it was found that feral cats had no negative impact on wildlife, most would probably be just fine with letting them alone.

    This isn't about wanting to hunt anything. Again, it's about biodiversity conservation.

    Your Comment: "Now here's a "scientific study" idea. Do you suppose there would be any interest in how much wildlife is destroyed because we have moved into their habitat? I realize that "we" brought the feral cats with us but I would be interested in seeing a study talking about how many animals and birds have lost their habitat due to the encroachment of humans - some of whom have never had a pet.

    Interesting concept? Maybe the Audubon Society, ABC and NWF should broaden their research horizons."

    My response: there are literally hundreds and hundreds of papers on the topic of how habitat loss/destruction impacts wildlife. Even a quick google search would have revealed this. Yes, this issue is probably a larger concern than the threat posed by feral cats....HOWEVER...the feral cat issue would be easier to correct.

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  13. I didn't realize I insulted anyone. I try very hard not to.

    Now, was I being mildly sarcastic? Why yes I was. I was not, however, sarcastic about the organizations mentioned when it comes to the work they do best. I thought that was clear by my having said that I have contributed.

    And I totally agree that pets should not be allowed to roam free. I know I mentioned that as well.

    I just find it interesting and sad that so many people wish to destroy a "problem" that people created. No insult - just sad.

    I'm sorry you took my dispute as an insult. It was not intended that way but people will believe what people will believe.

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  14. Michael,

    Thank you and thanks for stopping by to read my blog!

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  15. Alright, folks...as usual...discussion on this issue simply devolved into a digital screaming match, with insults and occasional profanity to-boot. Where no one listens to the other's point of view and folks are so ingrained in their own thoughts that they aren't going to change their mind.

    So, from this point on I've set up the blogger account to allow me to screen all comments before publishing them.

    I will delete any new comments related to this topic.

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  16. ...btw....I forgot to mention that I also deleted about 12 comments full of ranting, rather than actual discussion, which prompted me to make this decision.

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