Domestic cats an invasive species

The Polish Academy of Sciences added the domestic cat, Felis catus, to its list of invasive species. Cats won't be rounded up or anything, but their propensity to slaughter everything within acres of their homes is now well-understood—and understood to be a serious ecological problem: "They kill anything that catches their eye."

"A lot of [studies] show that much of the hunting that cats do is just invisible to us, invisible to their owners," Helmuth says. In one study, Helmuth put small video cameras on cats and followed what they did over most of a summer. She found the cats killed a lot of species in their neighborhood. Only 20% of the time would they bring their catch back home, leading many owners to believe their cats weren't causing trouble. More than 100 years ago, the Lyall's wren was entirely wiped out by a cat named Tibbles in 1894. Helmuth says cats have that kind of impact because birds and other species have never experienced these predators in their evolutionary history.

Some towns in Iceland are putting restrictions—kitty curfews—on when housecats can be outside, and some towns in the U.S. (e.g.) include cats in leash laws applied to outdoor dogs. The expectation people leash cats or keep them indoors is an emerging rage story for British tabloids—any legislation is likely to result in them announcing a unilateral declaration of war on swifts and voles.

[Thanks, Heather!]