By Chris Schultz Winsted-Lester Prairie Journal & Howard Lake Herald, Minn. April 13, 1998
Well fed and well armed, free-ranging domestic cats kill millions of birds each year
Reprinted from Fish and Wildlife Today, Winter 1998.
Is a fat cat a satisfied cat? Apparently not when it has birds nearby. According to a recent report by Wisconsin researchers, free-ranging domestic cats destroy millions of birds in that state each year.
Many of these tubby tabbies kill for fun rather than for food. Unlike wild predators, domestic cats hunt whether they are hungry or not. Professor Stan Temple of the University of Wisconsin (UW) calls cats "subsidized predators" because they receive a steady supply of food at home. "Pet cats can hunt longer and are less suspectible to disease than many wild predators," says Temple.
The problem is so severe that in 1997 the American Bird Conservancy (ABC) began a national campaign to educate cat owners about the threat to birds from cat predation.
"Like many cat owners, I once thought my cat was supposed to roam outside," says Linda Whiter, coordinator of the ABC's new Cats Indoors! campaign. "But the fact is that it's better for cats and for wildlife if they stay indoors."
Originally domesticated from an ancestral wild cat of Europe and Africa, cats are now considered a separate species (Felis catus). Though not legally classified as such, the domestic free-ranging cat is actually a harmful exotic species, like a zebra mussel with name tags.
The cuddly kitty that provides companionship indoors transforms into a ferocious feline hunter when it gets outside. UW studies show that the diet of free-ranging domestic cats is composed of 70 percent small mammals (predominantly mice and ground squirrels), 20 percent birds, and 10 percent other animals.
It's the bird kill that particularly concerns Joan Galli, a DNR nongame wildlife specialist. The most recent UW research suggests that the estimated 1 million to 2 million free-ranging rural cats in Wisconsin kill roughly 40 million birds each year. Galli and other Minnesota wildlife officials believe that the number here is likely comparable.
"Everything we know about the Wisconsin studies suggests that at least that many cats are doing the same amount of harm to birds in Minnesota," says Galli. "I think most people don't realize just what kind of damage domestic cats are doing to wildlife, particularly birds."
Bluebirds are among the birds harassed by cats, according to Dick Peterson, a bluebird expert and designer of the widely used Peterson bluebird-house pattern. "A cat is about the worst mammal there is on the bluebird trail," Peterson says. Particularly lethal, Peterson explains, are the cat's curved claws, which it uses to reach into the bird house and hook fledglings and nesting adults.
To keep cats from killing nesting bluebirds and their young, Peterson suggests mounting bluebird houses on a steel pole or a wooden rod covered by PVC pipe. (Under no circumstances should the house be near a tree or fence post that a cat can climb, he adds.) As an added measure, Peterson recommends mixing extra-hot pepper sauce with grease and putting it on the pole. "A cat or 'coon will get that on its claws or feet and then lick it off," he says. "If you use a hot enough pepper, it won't come back."
In addition to killing birds, free-ranging domestic cats also rob food from native predators such as foxes, snakes, and raccoons. In some study areas of Wisconsin, cat densities reach more than 100 animals per square mile-several times more than all similar-sized wild predators (skunks, foxes, and raccoons) combined.
Wildlife officials believe the only way to reduce the damage to birds by free-ranging cats is for cat owners to keep their pets indoors. Many municipalities currently have ordinances that require cats to be kept indoors or on a leash. However, these measures are rarely enforced, causing some bird fans to take matters into their own hands.
"You can live-trap a cat just like you would a raccoon, by using a can of tuna for bait." says Dorene Scrivener, chair of the Minnesota Bluebird Recovery Project. "Take the cat back to its owner and remind them to keep it indoors, or take it to the nearest animal-control center."
Cat owners might consider such measures extreme. But bird supporters say that something must be done to prevent cats from killing wildlife that's already under siege.
"Birds are having a hard enough time these days from habitat loss," says Galli. "As we try to save their habitat, it only makes sense to make sure that birds aren't being killed by our pets."
Prevent your pet from becoming a predator
Joan Galli likes catsbut only indoors. "Once they step outside, they become potential predators to native wildlife, particularly songbirds," says the DNR nongame wildlife biologist. Here are her tips to prevent pet cats from harming wildlife:
1. Keep your cat indoors. Kittens confined to the house will soon adapt. If you choose to let the cat out, keep it on a tether, or in a fenced area or enclosed runway. "Even if your cat is declawed and wears a collar bell, it can still catch and kill birds," Galli says.
2. Neuter your cat or otherwise prevent it from breeding. Obey existing laws that require licensing or neutering or initiate new laws if your community doesn't have them. To learn about local laws, call your local health department or humane society.
Keep feeders and bluebird houses away from trees or posts where cats can get to them. If a cat can reach a bird house, it can reach in and grab fledglings or nesting adults.
4. Don't release unwanted cats in rural areas. They'll either die of starvation or learn to become effective predators and eat wild birds. Take unwanted cats to an animal shelter or humane society for adoption or have them euthanized.
5. Don't feed strays. This maintains high cat densities that kill or compete with wildlife. Strays will often reproduce where there's a source of food creating large colonies of feral cats.
Studies in Wisconsin have found that the two most common causes of death for cats are disease and being run over by cars. For the good of cats and birds, it's best to keep your kitty indoors.