Back in high school, I read a poem called “The Prize Cat” by E.J. Pratt. As a cat owner and lover, I delighted in Pratt’s descriptions of a pure blood domestic tabby cat with a soft-mannered, musical purr. “The ribbon had declared the breed, Gentility was in the fur.” Essentially, Pratt muses about the tamed majesty of the now-domesticated feline. And then, a flash of instinct:
I saw the generations pass
Along the reflex of a spring,
A bird had rustled in the grass,
The tab had caught it on the wing:
Behind the leap so furtive-wild
Was such ignition in the gleam,
I thought an Abyssinian child
Had cried out in the whitethroat’s scream.
I think that was the first time I considered the predatory instincts of my beloved pet and, though it was unsettling, I didn’t think about what outdoor cats might be doing to bird populations on a wide scale.
In her recent article for the New York Times, Natalie Angier offers a bird’s eye view. Although Angier definitely editorializes—describing cats as bored, carnivorous tourists and recreational, subsidized hunters—she raises some interesting points.
It’s not hard to imagine the high number of feral and stray cats already feeding on bird populations, but to imagine our “tamed” pets killing birds by the billions may seem strange at first. Sure, they have room and board, but Angier argues that they are, nonetheless, members of an invasive species. She quotes Peter P. Marra, a research scientist at the Smithsonian Migratory Bird Center, in estimating that there are 117 million to 150 million free-ranging cats in the United States alone. In fact, Marra calls them “the most abundant carnivore in North America today.” (I mean, woah, is that true?)
Although Marra’s study of fledgling survival seems interesting, I wonder why Angier didn’t publish the numbers. All we read is that Marra studied two neighbourhoods: In Bethesda—“a largely cat-free” neighbourhood—fledgling survivorship is at 55%. In Takoma park—a place “crawling with outdoor cats”—the rate apparently plummets to 10%. The thing is, if we don’t know how many birds and cats were involved in the study, it’s hard to know if these percentages are statistically significant and what they mean for bird populations in various North American neighbourhoods. Though the issue may be big, this isolated two-neighbourhood sample seems far too small.
I don’t purport to know much, but if this article in the Journal of Animal Ecology is any indication, food chains, which include our introduced mammals, are much more complex than Angier implies.