The pitter-patter of little feet can be an endearing sound. But not if it's coming from your attic.

It's the time of year when the weather turns chilly, nudging mice, squirrels, chipmunks and even raccoons to seek the warmth of humans' homes. While the wild creatures may be cozy inside, they're also liable to chew on wiring and insulation, get into pantries to raid cereal boxes, and leave urine and feces throughout the house.

"The reason they move in is because the weather is changing," said naturalist Franklin Klock of the Carbon County Environmental Education Center in Summit Hill. "We see animals like field mice moving into wooded areas in the winter time because there's natural protection there. These animals don't know the difference between your house and a big tree. They are just doing whatever they can to get out of the weather and prepare for the winter."

John Marzen, co-owner of Marzen's Feed and Hardware in Franklin Township, is seeing more customers come in with complaints about wildlife invasions, mostly mice.

"This year, there's no shortage of critters. I always attribute that to a lot of rain in the summer. You get a lot more vegetation and bugs, and that runs up the food chain," he said.

Last year's warm winter also contributed a bump in the mouse population, Marzen said.

Human homes offer creature comforts

"Our homes are perfect for small animals because they find all kinds of nesting materials. Mice will make nests out of old blankets, out of newspapers, out of fiberglass insulation. In the woods, it's leaves and sticks and twigs and feathers and cattail fluff. But we have all this great stuff that they use, and they like that," he said.

Once the critters are cozy and warm inside, they look for dinner.

"Many times, they find a food source in these places, and that's what makes them stay," Klock said.

That food source can be Fido's food bowl, the cookies left out on the kitchen counter, or that forgotten pizza crust under a teenager's bed.

According to the Penn State Extension office, mice are active at night, but evidence of their activity can be seen during the day. Look for gnaw marks, nesting material, and mouse droppings, which are about the size of rice grains.

Why they should

stay outside

A couple of mice may not wreak havoc in your home, at least not right away. But a mouse can have five to 10 litters a year, each of about five babies.

Some small rodents, including mice, can carry diseases like hantavirus and Lyme disease. Another problem is the "ick factor."

"They're not leaving the area to eliminate, so they're going to the bathroom and making messes," Klock said. "Mice will build a nest and stay in that nest for a finite amount of time. Once it becomes polluted with feces and urine, they'll abandon it and move to the next one. That's why you'll find these caches and balls of shredded newspaper in drawers.

Although mice do chew, they aren't as liable to chew electrical wiring, causing fires, as are chipmunks, he said.

De-mousing

your house

The first thing we recommend are the good old-fashioned snap traps. They're fast and relatively painless. It's a quick death," Klock said.

"Poisons are the least recommended. The animals go through horrible pain. And when that animal drags itself somewhere else and dies, something else is going to eat that. Those toxins are in that carcass, and now we have what is called secondary poisoning. An animal that isn't a problem to you a hawk or somebody's cat is going to eat that (poisoned) animal, and they'll have those toxins inside them," he said.

"Mice are a number one prey item just about everything eats them. Once those poisons are out there, you're poisoning a whole wide, vast group of species," Klock said.

Also, poisoned mice will often die in inaccessible places, like inside walls, making it difficult if not impossible to remove the reeking, decomposing carcasses.

Marzen agrees.

"For your house, I never recommend using poison. You're better off putting out traps at least you'll know when you've got them," he said.

Glue traps are cruel, and may cause more problems than they solve.

"Glue traps are not a means of eradication. They just trap the animal. If that animal dies, it dies of starvation. Anything that gets stuck on there becomes prey for something else, so you're going to attract the other things. You're better off with a snap trap," Klock said.

For those too squeamish to dispose of a mouse caught in a snap trap, there are versions that hide the tiny corpse.

The fall critter invasion is not just into our homes; it's also into our cars.

"It's not a bad idea to check under the hood, and in the air cleaner," Klock says.

One person who works at the center had a car that wasn't running well. Her mechanic discovered that mice had cached food inside the catalytic converter.

The mechanic has since put a screen over the tailpipe.