Years ago, when I was briefly an adjunct faulty member in the Communications Department at Cornell University, I remember attending a faculty meeting where a full-time tenure-track colleague was giving an advance presentation of a paper he was soon to deliver. He had conducted an experiment to see whether negative political advertising was effective or not, and concluded, after a couple of controlled tests, that it was not. I asked him who his test subjects were, and he said they were volunteer students from Cornell. I asked how representative such a test could be, if the students were from an Ivy League school, and were probably among the smartest, most intellectual young people in the country. He couldn’t really answer. Clearly, his results were meaningless at best, but hey, he would soon be delivering a paper at a prestigious conference.
I’m reminded of that flawed study by the current cat fight over a new study claiming that feral cats are the primary cause of a rapid decline in the US bird population. The authors of the study, according to a heavy-breathing report in the New York Times’ Science section today, “scaled up local and pilot studies to national dimensions,” to conclude that wild and domestic cats kill an annual 2.4 billion birds and 12.3 billion small mammals a year in the US. If true, this would, they say, make the cat “one of the single greatest human-linked threats to wildlife in the nation.”
I love the decimal points applied to an amalgamation of small geographic studies that all, as the Times notes, “admittedly come with wide ranges and uncertainties.” Decimal points are great tools for implying mathematical rigor when there clearly was none.
The whole thing is of course ridiculous (like those periodic scary, and always seemingly scientific, reports claiming that Iran is building a nuclear bomb, or that Mali or Somalia is about to attack the US). Feral cats have been present in abundance across the US now for a good 150 years, as cats, a European import, have followed modern Americans to occupy the continent. And as European immigrants displaced the native human population, along the way killing off competing predators like foxes, weasels, wolves, lynx, bobcats, and pumas, not to mention raptors, snakes and owls, cats replaced those lost predators==at least where small prey are involved. And yet despite this long-running holocaust, the collapse of songbird populations has been a relatively recent phenomenon, corresponding, oddly enough, not to the dispersal of non-native cats, but rather to the also more recent phenomenon of suburban sprawl and the ubiquitous impacts of the chemical herbicide and pesticide industry.
What has been killing North American birds? Plenty of studies have reported that it is a loss of secure nesting sites in boundary undergrowth, such as is found on the edge of forests and groves, a bane of suburban homeowners, a loss of wetlands, another prime nesting area for many bird species, a loss of connection between sections of woodland, the mowing or plowing up of grasslands, and of course the widespread use of pesticides to eliminate the flies, mosquitos, and other bugs that are a mainstay of the bird food supply in summer months.
A second problem with this cat “study”: If anything, since feral cats have been replacing decimated native predators like the bobcat, weasel, fox, snake and hawk, to accurately assess the true impact of these “killer cats,” one would have to first establish what the historic native predators had been killing, and then deduct that toll from the estimated cat kill count. This was not done in this study so even if their numbers were correct, we’d have no way to know the net impact of cat kills on bird mortality.
Anecdotally, I should add that I’ve walked miles in the forests of the Catskills and even more locally outside of Philadelphia, and away from houses and communities, I have never spotted a feral cat. These animals, even if they are afraid of people, tend to hang around in the vicinity of humans, where there is garbage to be had, as well as favored prey like roaches, mice and rats, which are attracted to human detritus. It seems quite a stretch to say that feral cats are decimating small birds, most of which are well away from human habitation in the country’s still vast forest areas.
Meanwhile, as for the more populated areas where feral cats are readily found, I can tell you that on my own 2.3 acres in an outer suburb of Philadelphia, there are no snakes (I am a good snake hunter and I have found only one garter snake on the grounds, which are pretty wild and unkempt, in the 16 years we’ve lived here–and that was years ago). We have no weasels, only an occasional visiting fox, and the lawn is swarming with rabbits and woodchucks because of a paucity of predators. Our own cat, FuFu, is almost the size and bulk of a woodchuck, but he’d be hard-pressed to tag one, much less take it out. He is okay as a mouser, but half the time he doesn’t kill them — just mouths them and plays with them. He could never catch a bird. Besides, he’s an indoor cat exclusively. That said, the feral cats that occasionally raise their litters in our barn are clearly not denting our rabbit or gray squirrel population, and don’t seem to be getting at the birds either. I suspect they focus on deer mice, which we have in abundance, and which are much easier to catch.
The three authors of the study in question, Scott R. Loss, Tom Will and Peter P. Marra, state in their abstract that they have “no competing financial interests” and that may be true. Although their study reads like it was prepared by a PR agency for Monsanto or the wind-turbine industry, they may be simply lazy researchers who haven’t given enough critical thought to the validity of simply extrapolating from a bunch of small studies to reach a continental conclusion. Either that or they are dog people.
The way I see it, this report on “killer cats” is for the birds.
(The author is a life-long cat owner. Among his colleagues at ThisCantBeHappening are cat owner John Grant, multiple cat owner Linn Washington, Jr. and former cat-owner Charles M. Young.)