Thursday, November 1, 2012

That Darn Cat!

The number of feral cats round these parts is staggering.  Last year, I posted a round of mugshots from individuals skulking around the property (see here).  Since that time, our local feral cat population has not appeared to decline much.

This summer we experienced an unusually long period of drought (weeks long, in fact).  We don't normally feed the birds because we have a nice variety already without spending the cash on birdseed.  Yet, after seeing American Robins hopping around our back porch trying to drink water from the saucers below our potted plants....we caved and put up a makeshift bird bath. 

It wasn't long before Sylvester started stalking around the perimeter of the bath, watching the inhabitants.  I made sure that every puddy-tat I saw got chased off...hoping to instill in them some negative association of the Pavlovian variety with our house. 

Didn't seem to work, though.

A manuscript published several years ago estimated that feral cats and pet cats allowed to roam free kill roughly 1 BILLION wild birds annually in the U.S. (and this is a conservative estimate; Dauphine and Cooper 2009). 

Believe it or not, I haven't seen a cat take a bird on our property (although I'm sure it happens).  I have, however, obtained evidence that they get other wild prey (see below).

Several of the original inhabitants, first photographed when we arrived over a year go, are still around......although a few seem to be gone.

There are are also some new faces.

Calico Joe
This one had been a constant figure on the property from last fall through early spring.  But I haven't seen much of old Joe this summer and fall.  He may no longer be around....although the other night as I drove up to the house I saw a kitty that looked very similar dart across the street.  Might have been him.

Mr. Marmalade:
He's definitely been around since last year and was the individual I captured a picture of killing a chipmunk a year ago.  He must be a wily sort.  Others have come and gone since last year, but Mr. Marmalade keeps on showing up.  He's the only one that I've consistently gotten pictures over the last year.  Probably his coat color helps him blend in.....something useful for hunting and hiding.

I first saw this one in early spring 2012, but he has been a permanent figure on my cameras since.  I probably have more pictures of Tiger than any other feral puddy tat on-site.  Although I don't think he's been around as long as Mr. Marmalade, he has staying power.

Mr. Boots
I only have one picture of Bootsie from this spring.  He almost looks like a Siamese, but I haven't gotten a face-shot of him, and he's only been through once.

I don't think I'd seen this one until late September of this year.  Yet, since that time she/he's been photographed consistently.  He/She seems a bit small, so might be a juvenile.

Another new one from late summer 2012.  Also looks on the small side, like it might be a juvenile.  Since late August, he has shown up on my cameras frequently. (Note; this picture also portrays how dry it was this summer.  Compare this picture to the picture taken of Mr. Boots above at the same location in May).

These are just the cats that have passed this one camera location. There are others on-site, and some that appear to have moved on.

For example:
Here Tiger is following a long haired such-n-such that I saw commonly last fall and in the early spring, but has been AWOL since.

There's also El Diablo, whom I've posted about before.  He was everywhere this spring, but has been gone for months.

BUT....don't be fooled by the cutesy names.  These kitties have claws!  And they use them to great effect on native wildlife.

What I find the most un-fathomable is that, of the literally tens of thousands of camera trap pictures and video clips generated from projects I've been involved with....I've only ever gotten pictures that definitively show predation being committed by one species:

Felis catus

No fox predation shots, no coyotes, no nothing.  But I have a numerous pictures of kitties carrying a meal of native wildlife in their mouth.

The first of these incidences involved an Eastern Chipmunk (Tamias striatus), which was in my post from a year ago.

There have been more acts of predation captured since that time....

Here is a picture of Calico Joe from last fall, as he saunters by with a bit of din-din.

After zooming in a bit, you can see he's carrying something in its mouth, which is the right size for a rodent (Peromyscus is common on site).

Below is Tiger trotting home with his meal of hapless Eastern Chipmunk.

The new crop of kitties don't want to be left out either.  Below is a shot of Whiskers with a mouse in tow (another Peromyscus sp.).  Note the set of eyes watching him in the background.  I have no idea what they are from.

Of course, we already know that Mr. Marmalade is very effective at catching wildlife.  But here's another shot of him in the act again (appears to be another Peromyscus).

Whenever I'm depressed about the impacts of feral cats on native wildlife, I like to watch this clip from the Muppet Show.  Rowlf sings The Cat Came Back in a way that makes me smile every time...


Literature Cited

Dauphine and Cooper. 2009. Impacts of free-ranging domestic cats (Felis catus) on birds in the United States: a review of recent research with conservation and management recommendations. Proceedings of the Fourth International Partners in Flight Conference: Tundra to Tropics, p 205-219.

Further Reading .

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.


  1. Great post TB. I am blown away by the number of individual feral cats you got at a single locale. Good god! Don't know how you feel about it (I guess my take is that it is better than nothing) but are there any vet clinics in your area that do free spay/neuter of feral cats. It is a very common thing in CA, but it might be because we are a bunch of wildlife loving hippies. You could set live traps and at least keep them from breeding.

  2. Whoa, seriously a lot of cats. We have 2-3 that are roaming around our neck of the woods. One is extremely friendly and my roommate actually started petting it and BROUGHT IT INTO THE HOUSE for a little bit one night. Then she discovered that the cat ("Nacho"- notched and frostbitten ears) was covered in ticks and fleas, and had God only knows what else. I just bought a puppy and have forbidden the roomie from bringing that cat into the house ever again. And I don't even want it hanging around outside! I'm an animal lover, but I'm not ok with this cat. I could never *dispatch* the cat, but I want to hang up a Wanted poster down the street asking the owners, if there are any to keep this thing inside!

  3. (quoting): I've only ever gotten pictures that definitively show predation being committed by one species...

    Why do you think that is? Is it just the volume of cats, or do the behaviors of the others (foxes, coyotes, etc.) preclude these types of photos being very common?

  4. I'm assuming it's a combination of the high density of cats on-site and the fact that they are very effective predators. There are not as many fox/coyotes on the property. If they were in higher density, I would have a higher probability of catching photos of them catching prey.......

    Although Canines are wary and (in theory) could avoid the cameras, this is also true of feral cats. Furthermore, Canines acclimate to the cameras over time, which again is true of the cats. In fact, I have numerous pictures of red fox passing that camera....and a few coyote pictures. They appear undisturbed by the presence of the camera now (or, at least, no more so than the feral cats). Despite this, with all of the cameras I've had on that site over the last year, I've never gotten a picture of any actual predation that didn't involve a feral cat.

    This is also gets to the heart of the problem with feral cats: large numbers of them (particularly compared to other predators) = high predation rates on wildlife. No doubt fox and coyotes (and hawks, etc.) get lots of rodents....but they don't exist on-site in as high of densities as do the cats.

  5. That makes sense. It seems a lot of the research focuses on feral cat impacts on prey populations. What about up the chain? Do feral cats out-compete other, natural predators? For that matter, how often do the feral cats end up on the food chain of the bigger, natural predators?

    1. Great questions!

      Evidence to support whether feral cats out-compete native predators is something I'm not sure of. It's often suggested that this occurs....but I can't think of any studies that have investigated this off the top of my head (although some may exist). Obviously, feral cats (and house cats allowed to roam free) have an advantage over wildlife: they are often provided food, water and shelter by humans in some form,so don't have the same difficulties that native wildlife does. Thus, it seems likely they could easily out-compete native predators.

      There has been research looking at the interaction between cats, coyotes and bird populations in the Southwest. Crooks and Soule (referenced above) coined the term "meso-predator release" to describe this interaction. In areas where there were no coyotes, the populations of middle-sized (or meso-) predators were higher and bird diversity was lower (because these meso-predators like cats were eating them). In areas with the bigger predator (i.e. coyotes) meso-predators were kept in-check and bird diversity was much greater.

      There are also other negative impacts to consider...such as disease transmission. Feral cats transmit rabies, tapeworms, etc. When their densities increase, the rate of transmission of communicable diseases amongst themselves AND to native wildlife also increases.

  6. Sounds like you have your own cast of the Usual Suspects. Since you are able to identify individuals based on color pattern, would there be any way to do long-term survivorship of feral cats at your research station? Any sort of population analysis possible? Also, the Muppet's tune has never made me feel so good about cats.