Friday, February 01, 2013

Birds, cats, science, emotion, and compassion

If you follow any news media online, chances are you have read about a study that came out this week, estimating the numbers of birds and mammals that are killed by domestic cats (pets and feral) each year. And, even from respectable, restrained news outlets such as NPR, this story was accompanied by sensationalist headlines, such as "That cute kitty is a killer!" Well, duh. Anyone who is familiar with cats, or has watched an episode of "Tom and Jerry", knows that cats have a desire to kill small animals. That's why humans found cats useful, long before the advent of the Internet and cat videos.

A disclaimer: I am an avid bird watcher, and I have cats. Three indoor cats, to be exact, and three cats that hang around my house outdoors, the remnants of a once larger "cat colony" that showed up uninvited here the summer after we moved in, nine years ago, in the body of a promiscuous female I called "Evil Calico". The bird loving me and the cat loving me had intense internal struggles about how to handle the outdoor cat population; bringing excess cats to a shelter was not an option around here, and although we have a .22 rifle, I never felt right about the killing solution. As it turned out, the number of cats eventually dropped to two females, one male, and a kitten has not survived to maturity in two years. This "cat herd" did provide my Best Cat Ever, though:

Anyway, back to cats killing birds. The news releases about the study provoked the usual response: bird watchers shared it on social media, and my local birding listserv lit up with posts from birders getting in their two cents' worth about "irresponsible cat owners", "this is astonishing", etc. I, being the scientifically trained skeptic I am, wondered if there was more to the story than the sound bites and headlines. Something about a study that could provoke such rancor did not seem objective and scientific to me.

I read the published paper, which can be found at no cost here. Since I seem to have left that part of my brain that deals with methodology and statistics behind as soon as I defended my Master's thesis, I was glad that another source, Vox Felina, did a thoughtful job of critiquing the methodology and conclusions.

Now, I think we can find some points that cat people and bird people can agree upon. And, I think the media did a disservice to both groups by portraying each as single minded fanatics. One, cats, if left to roam, will kill what they can. Sometimes they won't even eat it. (Humans have this same disgraceful habit) Two, there are specific areas, such as islands, where predation by cats, whether pet or feral, has contributed to the decline, and even extinction, of some species. For these areas, a recovery plan, if feasible, should definitely address the harm done by cats.

...a study that gives numbers without context is meaningless. Do we have population estimates of the bird population in the US? As a fish biologist, I know how difficult it is to get an accurate estimate of the population of fish in a small lake.
...a study that gives numbers without any estimates of what species are killed, and in what proportion to the total, is meaningless.
...The issue of mortality is hard to convey to a public who does not have a basic understanding of animal population dynamics. A certain number of any species will succumb to mortality, without affecting the overall population. Certain species that are adapted to the urban environment may occur in higher numbers than what would be expected in nature, and may also be preyed upon by urban cats.

And then we have conflicting issues of compassion. The drive of compassion in humans is undeniable; it is what keeps us civilized, it is what gives us hope. One side has compassion for the prey, the poor vulnerable victims of a predator brought upon all corners of the earth by humans. One side has compassion for the cats; it is not their fault they are here, and that they have an urge to kill (a Sylvester and Tweety cartoon comes to mind, in which Sylvester attends a twelve step program for his "addiction"). Cold, hard science tends to disregard compassion. In my career I have seen, on one hand, ridicule for people who bring "nongame" species in (i.e. songbirds) for rehabilitation; on the other, I have seen many people who choose wildlife management as a career who think the only good cat is a dead cat.

Can we find common ground? I think the media hype surrounding the "study" that came out this week only serves to divide people. As is the case with most stories that qualify as "news" these days.

UPDATE: Apparently I am not alone in thinking this way. NPR blogger Barbara J. King questioned the statistical validity of the study,  as well as its usefulness:
Demonizing cats with shaky statistics, however, won't help us build the pillar of understanding required to strike a satisfying balance between the needs of cats and their supporters with the needs of wildlife facing a feline threat.
There is a (mostly) thoughtful discussion in the comments section of King's blog post.


webb said...

A thoughtful, reasonable post. Glad you took the time to actually read the study and the analysis.

Deb said...

Thanks Webb, that was my goal, to be thoughtful and reasonable. There are so many more angles to this story I would have liked to comment on, but are beyond the scope of one blog post. The bottom line: might as well consider cats as part of the ecosystem we humans have created.

Jayne said...

I cringe when I see neighborhood cats, left to roam, sitting under the swing in my birding area and stalking my feeders. And I do silently curse their owners for allowing them to roam. On the other hand, as you said, there are two sides to every story, and I wonder how much this keeps the natural balance of bird population. I mean, I have no problem if a hawk gets some of the birds I lure to my "hawk feeding station" and yet I loathe the cat just "being a cat?" Lots of ways to think about this issue I suppose. I am the one who sets up this artificial feeding platform that others simply take advantage of, as they are programmed to do.

Deb said...

Jayne- I forgot to mention that I do strongly believe pet cats should stay indoors, especially in urban and suburban neighborhoods. I don't know if there are any studies available on what percent of owners keep their cats indoors, but I suspect that may be increasing due to public awareness campaigns. But this study pointed out that more predation likely comes from feral cats, although it is difficult to come up with a precise population estimate for them, and therefore calculate total predation

Deb said...

Arrgghh! My ipad won't let me continue typing after I've deleted something. I just wanted to conclude that it is a more complex issue than can be contained in a media sound bite.

YonassanGershom said...

Very good post. We have a colony of cats on our 15 acres here (at one time there were 16, but now down to 9 kitties, all fixed) that we inherited with the land -- part when we moved here and part when there were so many foreclosures around here and people started abandoned their cats. I make it a rule that any unclaimed cat who shows up here gets neutered or spayed, and at present the colony population is slowly declining from old age.

Yes, they go outside and that is why we do not have bird feeders. Most of what my cats catch are rodents, which makes them very useful around the chicken coop. Sometimes they do get a bird -- when the Slate-Colored Juncos migrate through each spring, one or two usually succumb. But it isn't the whole flock, and I find myself wondering if these are not the weaker (or stupider)ones. Maybe the cat predation actually strengthens the flock, so only the stronger ones make it to Canada to breed? The flocks do not seem any smaller when the come back through in the fall.

I feel sad when they do get a bird, but I also felt sad when a Red-Tailed Hawk ate one of my chickens right there in the chicken yard. (See my blog post on that at However, that is nature. Death is part of life.

Deb said...

YonassonGershom- That's a good point about the bird feeders. I have gone to great lengths to try and make my bird feeders cat proof, but a cat can still jump up almost four feet in the air and sometimes nab a bird that maybe had slower reflexes than the others, or perhaps was just unlucky. Junco time is an open invitation for cats, since these birds feed mostly on the ground. However their numbers never seem to suffer. That is another question- how much do bird feeders influence cat predation on birds, since birds are concentrated at feeders?