When Sheryl Poulsen and her husband bought their house 10 years ago, they didn't plan on turning it into a rest stop for wayward felines.

And they wish their uninvited guests would leave.Ever since the snow melted on their third-of-an-acre yard last spring, the Poulsens have been besieged by stray cats who insist on using the family's lawn as a litter box.

The Poulsens are not alone. Other residents of their Cottonwood Heights neighborhood have similar problems. Some have resorted to bee-bee guns.

"I don't mind cats," Poulsen said. "I don't mind if they walk through my yard. But it's when they use my yard as a litter box that I mind."

According to Salt Lake County Animal Services Director Peggy Hinnen, stray cats are booming all over the valley. Her employees picked up 172 dead cats from roads between July and September of this year, compared with only 112 dead dogs. They impounded 899 cats during that same period, compared with 885 dogs.

"Cats are becoming the pet of choice in our society," Hinnen said. People are looking for pets that require less care and attention. Many cat owners figure their pets are self-sufficient. But they are wrong, Hinnen said.

"We've domesticated cats just like we have dogs. They're not nearly as self-sufficient as people think they are," she said.

What intrigues Poulsen is that the cats relieve themselves directly on her lawn, the type of behavior one would expect from a dog. Her husband has to shovel the lawn almost nightly, and Poulsen worries about the health of her four children, especially the younger ones who like to play in the yard.

Jim Wilson, a North Salt Lake veterinarian, said it is not unusual for a cat to relieve itself on grass.

"Some cats will go on the grass and go through the motions of burying it without actually doing so," he said.

But he warns that the cat feces could be a health threat to young children, who face the danger of acquiring parasites.

Poulsen doesn't want to resort to trying to hurt the cats. Although she believes they are stray, she isn't certain. "You can't exactly follow a cat home," she said.

She often finds cats sleeping in her garden, particularly amid corn stalks, and in a trailer parked in the yard. She wouldn't mind so much if the cats used a weed patch along the side of the house as a litter box. The family plans to pour concrete over that section soon. But the cats ignore the weeds and head for the grass.

Poulsen called the Salt Lake County Animal Services Division and was told she could use a cat trap - a steel cage with food bait and a trip pad that would shut the door once the cat was inside. But Poulsen would have to pay a $30 refundable deposit from which $3 would be deducted each day as rent.

She was disappointed. "What am I paying taxes for?" she asked, noting her father got an immediate response from state Fish and Game officials when he found a quail in his yard. "I've even thought of shoveling all this stuff and taking it down to the county and saying here, you take this."

Hinnen said the division doesn't have enough employees to begin rounding up stray felines. County ordinances do not require animal services officers to control stray cats, although Hinnen expects that soon will change.

Hinnen also believes cat owners soon may be required to license their pets, similar to requirements placed on dog owners.

In the meantime, Poulsen can think of few other solutions to her problem, short of buying a dog.