"If your house is not animal-proof, you could easily find yourself sharing winter quarters with a skunk, for example, and we all know what happens when they get irritated," said Washington State Extension Service analyst Dave Pehling.
While skunks are relatively infrequent stowaways in this region, raccoons, opossums, rats and mice aren't. And an occasional otter has slithered under beachfront houses, Pehling said.
Three simple ways to keep home pests at bay:
Block access: Cover all potential entrances to crawl space, attic, garage and storage areas. Cover vents with quarter-inch or smaller galvanized steel screen.
Don't offer easy meals: Lock or place elastic cords on solid-bottom outdoor trash and compost bins. Pick up and bury fallen fruit and vegetables. Keep bird feeders apart from living quarters.
Control moisture: Damp wood and insulation are ideal habitats for some of the most destructive insects and for some animals. Where leaks or flooding occur, clean up promptly and thoroughly.
He and other experts agree that keeping wildlife out can be as simple as not inviting them in.
"It's easy to prevent wildlife from being around your home, and right now is a great time to do it," said Zibby Wilder, public affairs officer for the Progressive Animal Welfare Society in Lynnwood. "Inspect the outside of your house to make sure there are no open invitations."
Holes or gaps in crawl-space covers and vents, attic dormers and vents, windows, and garage and other doors are the primary means of entry. A raccoon, for example, can get into any opening big enough to let its whiskers pass. And a rat can chew open even a tiny hole.
The experts recommend repairing holes and cracks in the walls, roof, attic, crawl space and garage and covering necessary openings, such as vents, with quarter-inch galvanized steel screen. Zibby noted that homeowners should take care not to overlook the obvious, such as pet doors.
Reducing incentive is equally important. A trash can or compost bin with a loose-fitting lid, fallen apples, lots of pet feces and outdoor pet food dishes all invite visits from hungry animals. The solutions are as simple as locking bins, cleaning the yard and moving Fido's dinner indoors.
The same truths apply to smaller but often more damaging pests. In addition to screened vents, Pehling said caulking and weatherstripping around windows and doors, and maintaining a dry crawl space, are essential to keeping insects out.
"Moisture is a big problem," he said. "Check your vapor barrier and ventilation under the house. If you're moisture level gets much above 15 percent for long, you're opening yourself up to trouble."
Moisture makes a fine habitat for rodents and bugs. Both the powder post beetle and carpenter ant rely on moist environments to ease the way for infestation.
Once an unwanted visitor has gained a foothold in your home, how do you get rid of it? Determining what youre dealing with is an important first step. In the case of rodents, said Townsend Pest Control manager Jeff Calkins, you've likely got a rat if you hear gnawing or find bite marks.
"If you just hear scurrying inside the house at night, it's probably mice," he added.
If you suspect rodents in or near the house but have no visible evidence, Calkins suggests setting plates of whole peanuts in the crawl space and attic and checking back a day or so later. If they're gone, you're probably right. Calkins added that rats can be hard to trap.
For larger mammals, Pehling recommended trying exclusion as a first step.
"You're going to put some tracing dust outside of the house and watch for prints," he said. "Then you'll probably spend the better part of a night on your belly in the dirt watching for it to leave. When it does, you block access to re-entry."
Pest control services like Calkins' and a few licensed wildlife trappers charge to capture animals or poison them. State law requires that all trapped nuisance wildlife be euthanized or released elsewhere on the same property, Wilder and Pehling said.
As for insects, baits and poisons are available for consumer use.
Calkins cautions people not to try and poison the small, black moisture ants they find in their kitchens, however.
"Spraying moisture ants is the worst thing you could do," he said. "It sets the ants into a state of panic, and they take their larvae and spread them throughout the house for safekeeping."
He recommends moisture ant bait or professional treatment instead.
As with any contractor, the Better Business Bureau recommends checking the license and record of potential pest inspectors and trappers. And whether you call in a pro to deal with existing visitors or not, all the experts agree that deterrence is the surest choice when it comes to unwanted winter guests - be they clawed or microscopic.
Kristin Fetters-Walp is a Lake Stevens freelance writer.