Cats may be great at keeping your house mouse-free, but let them outside and they could become part of a major environmental problem. According to a 2013 report published in the journal Nature, cats are one of the biggest human-related threats to ecosystems around the world. In the U.S. alone, they kill between 1.3 and 4 billion birds and between 6.3 and 22 billion mammals every year.
People have struggled to find ways to prevent outdoor pet cats from adding to the body count with solutions like creating enclosed backdoor “catios” or by banning outdoor cats altogether. But recently, two unrelated groups of scientists each found that forcing Fluffy to wear a large, brightly-colored collar while she’s running around outside can make a dramatic difference in the rates of dead birds she drags back home, Conor Gearin reports for The Atlantic.
Go to any pet store and you’ll likely find a wall of cat collars designed to keep the furry murderbeasts from claiming new victims whenever they go outside, whether by using loud bells or trying to slow down their lightning-quick strikes. In this case, both studies looked at one cat collar brand that uses bright colors to warn birds that they are being stalked.
Unlike many small mammals that rely on their sense of smell to detect and avoid predators, birds can see color extremely well. While most mammals only have two color pigments in their eyes and primates (including humans) have three, birds and some lizards use four color pigments, Gearin reports. Usually this helps them find food and mates, but that extra pigment also allows them to easily spot a cat wearing a big, rainbow-colored collar.
"They're best used by owners whose cats catch a lot of birds and lizards and either don't catch a lot of mice and rats, or their owners don't care whether they catch mice and rats," Catherine Hall, the Murdoch University Ph.D. student who authored one of the studies, said in a statement.
While this may be great news for birds, these collars won’t do anything to stop cats from going after small mammals that may be endangered, especially in places like Australia where some conservationists believe that cats are responsible for almost all recent small mammal extinctions, Cara Giaimo writes for Atlas Obscura.
And even if all the pet cats got collared, they are just a small fraction of the world’s bird-killing felines, University of Nebraska biologist John Carroll tells Gearin. Feral cats are also big-time bird hunters with no human owners to curtail their killing.
“There’s some value to it,” Carroll says. “But it doesn’t get to the root of the problem.”
So while it’s far from a total solution to the threat, if your kitten has brought home one too many bird carcasses lately, this rainbow collar might just do the trick.