The Purrfect Murderers

There’s an old saying “when the cat’s away, the mice will play,” which means that when the authority figure isn’t around, his or her subordinates, students, etc. often act without concern for the rules. Like most idioms, the saying isn’t meant to be taken literally, so let’s not — at least not as it pertains to the mice. But for the cats, let’s. When the cats are away, what are they up to?

If they went outside, it’s probably murder.

Let’s start with this, a low-quality YouTube video uploaded about five years ago, which to date has fewer than 10,000 views. If you watch the video — and you should — you’ll see a bird and a cat playing a game of cat and mouse. The bird flies at the cat repeatedly, as if to taunt it, and the retreats. But, as the title of the video (“Ninja Cat Catches Bully Bird In Mouth In Mid-Air”) gives away, the cat ultimately wins. About 53 seconds into the clip, the cat does this:

In other words: when the cat’s away, it’s bad news for the birds. Very bad news.

In early 2013, a team of researchers shared the results of a study exploring just how bad. And according to Peter Marra, an ornithologist for the Smithsonian’s Conservation Biology Institute (via USA Today) who helped lead the investigation, outdoor cats are “the single greatest source of anthropogenic mortality for U.S. birds and mammals.” (If you had to look up “anthropogenic,” don’t worry, I did too — it means “of, relating to, or resulting from the influence of human beings on nature.”) The total cat-driven bird death toll? There’s still some debate, but it may be as high as 1.4 billion to 3.7 billion per year.

By and large, the “outdoor cats” aren’t pets. They’re feral felines that roam the streets, parks, forests, and the like. That said, some of the outdoor cats are, in fact, pets — just ones that are given the freedom to roam around their owners’ property or prowl the neighborhood. As a result, there have been some creative solutions proposed.

In Australia, for example, one politician proposed a 24-hour “cat curfew” — effectively, a ban on allowing your cat outside at all in areas with species which were endangered by the presence of outdoor cats. (Cats could go outside if on a leash.) The aim was to protect birds and other at-risk animals and in a way, the cats themselves; the Australian government saw feral cats as an invasive species and any cats out on their own were subject to whatever anti-feral cat measures en vogue at the time.

In the U.S., an inventor named Nancy Brennan came up with a less draconian measure: she wanted to turn cats into clowns. Here’s a picture:

That rainbow thing the cat is wearing is called a “Birdbesafe collar,” which Brennan invented. Per the company’s website, the collar reduced the number of birds caught by collared cats by 87%. The collars work, per Brennan’s company’s website, because birds can easily pick out the colorful patterns — and can figure out that something’s amiss, so they better fly off.  Unfortunately, per the Audobon Society, the collars proved unpopular among cat owners — “almost 80 percent who participated in [a study measuring the collar’s efficacy] said afterward that they wouldn’t use the collar again, citing reasons ranging from personal taste to the cats’ (perceived) discomfort.”

Of course, the birds attacked by un-collared cats were probably less comfortable.

Bonus fact: Cats’ innate ability to hunt mice make them a welcome addition to many ships, especially those which are at sea for long periods of time. As Wikipedia notes, rodents were (and are) a specific problem for seafarers; the pests “can cause damage to ropes, woodwork and eventually as technology progressed, electrical wiring;” they “may devour the foodstuff carried to feed the crew;” and they carry diseases. A cat onboard as part of the crew (informally) could prevent a lot of these ills. The Titanic, for example, had a cat named Jenny specifically on board to catch rats. (Jenny, like many of the rats she didn’t catch, went down with the ship, but a few dogs managed to make it into lifeboats.)

From the Archives: Window Pains: Birds also have another threat out there: windows. (The bonus item on that one may be, uh, redundant. Oops.)

Take the Quiz: Six animals, six languages: Pick the English, Spanish, French, German, Italian and Latin words for bird, cat, cow, dog, fish and horse.

Related: A base-red, polka-dotted Bebirdsafe collar. Cat not included.