Look out, lizards! Birds, beware! Run, rodents, run!

There is a predator slinking through the grass. She is quick, but she is not a weasel. She is clever, but she is not a coyote. In fact, this predator is not a wild animal at all. Her name is Scruffy, and she is an ordinary house cat.

Scruffy likes to go outside and hunt even though she has plenty of cat chow to eat at home. After all, catching critters can be fun.

She hears the flutter of feathers or spies the twitch of a tail, and then she attacks. Hardly any small animal stands a chance against Scruffy's quick paws and sharp claws.

Playing "cat and mouse" might be fun for Scruffy, but her game is not fair to wildlife, including species that may be threatened or endangered such as the Kirtland's Warbler. Unlike predators such as red-tailed hawks, raccoons, and gray foxes, domestic cats are not a natural part of America's ecosystems. In fact, pet cats did not even exist in this country until the early European settlers brought them here. People wanted cats to eat mice and rats around their farms, but nobody guessed how much trouble cats could cause beyond the barnyard.

Domestic cats, officially considered an invasive species, kill a lot of wildlife. "Exact numbers are unknown, but scientists estimate that nationwide, cats kill hundreds of millions of birds, and more than a billion small mammals, such as rabbits, squirrels, and chipmunks, each year.

One cat alone can kill up to 1000 small animals per year. This might not be such a big deal except that there are now about 70 million outdoor cats in the United States. With so many cats on the hunt, some small animal species are even in danger of extinction. In southern Florida, for instance, cats have taken a toll on remaining populations of endangered Lower Keys marsh rabbits and Key Largo woodrats.

What's worse is that songbirds, rodents, and reptiles aren't the only ones hurt by hunting house cats. Bobcats, kestrels, and other wild predators can starve to death when cats kill the small animals that they need for food.

Does this mean that cats are better hunters than wild predators? The answer is yes, but mainly because people feed cats. Cat chow and table scraps give cats more energy to hunt than predators who don't get dependable dinners from humans. And even with a full belly, Scruffy's natural urge is to catch all the critters she can.

Of course pets are our pals. We can't blame them for "bad" behavior - hunting is just part of their animal instinct. But when they are allowed to run loose outdoors, pets become a problem. So, how can we keep our kitties and watch out for wildlife? The solution is simple, and you can help. Here's how:

• Keep cats indoors or in an enclosed outdoor pen.
• Move any birdbaths, bird feeders, and birdhouses in your yard away from places where cats can hide.
• Get your pets spayed and neutered.
• Make sure your pets have all their shots so that they won't spread diseases to wildlife.
• Only keep as many pets as your family can care for.
• When you see a stray dog or cat, call your locak Humane Society or other animal rescue organization so that they can take the animal to a shelter.

You can make a big difference just by taking good care of your own cat. Encouragingly, Mother Jones reported in 2011 that "the American Bird Conservancy campaign to convince pet owners to keep cats indoors has had some success-bird deaths have declined by a third in areas that passed ordinances against free-ranging cats."