Cat Wars: The Devastating Consequences of a Cuddly Killer by Peter P. Marra and Chris Santella Princeton University Press, 212 pp., $24.95

Dogs may claim the oxidized trademark of “man’s best friend,” but in this country pet cats outnumber dogs by as much as 20 percent. Nearly half of American households are home to one or more cats, and we treat our 86 million felid companions remarkably, even extravagantly, well. Driven by their fussy palates, we spend $7 billion a year to feed them, to try comically elaborate medleys like “tuna in crab surimi consommé” or “Pumpkin Jack Splash.” We invest another few billion dollars annually in cat veterinary care, cat toys, cat litter, catnip, a little witch’s hat for Halloween. We reward funny cat videos on YouTube with hundreds of millions of views.

Yet even as we make such efforts, we admire cats for not quite buying into the deal, for their legendary independence and aloofness. Dogs may obey their masters and aim to please; but cats, their human partisans will proudly point out, cannot be tamed or herded. Cats are still wild at heart.

In the view of Peter P. Marra and Chris Santella in Cat Wars, the jaunty image of the house cat as a kind of lap-sized leopard and the powerful, almost parental love that cat owners feel for the increasingly popular pet obscure another, darker truth about Felis catus. Free-roaming domestic cats, they argue, are an environmental menace of staggering and still-escalating proportions. They are “cuddly killers” that butcher tens of billions of songbirds, small mammals, reptiles, and lizards each year and push vulnerable species toward extinction. Cats hunt when they are hungry and hunt when they are full. “In the United States,” the authors write, “more birds and mammals die at the mouths of cats than from wind turbines, automobile strikes, pesticides and poisons, collisions with skyscrapers and windows, and other so-called direct anthropogenic causes combined.”

Marra, who directs the Smithsonian Migratory Bird Center in Washington, and Santella, a journalist, attribute about a third of the annual cat-linked carnage to pet cats that are allowed to come and go as they please. The rest is the work of unowned cats: former pets that were abandoned or wandered off—otherwise known as strays—and the feral offspring of strays. The loose-cat problem is not limited to the US. The prestigious International Union for Conservation of Nature lists Felis catus as one of the hundred “worst invasive alien species” in the world, right up there with the Anopheles mosquito, the zebra mussel, and Dutch elm disease.

Not everyone is convinced that free-ranging cats represent a crisis of malarial proportions, particularly not if it means stray and feral cats will be rounded up en masse and delivered to animal shelters, where they are likely to be exterminated. There’s a reason the book…