Nesting is a particular problem, Miller says, because many animals like to return to the same nesting spot year after year. And if that spot happens to be your attic, they'll try hard to find a way in. If an animal has her young in your house, make sure to remove the whole family, or Mom will find a way back in, no matter how diligently you try to block her path, says Terry Rastetter of Critter Control in Alliance, Ohio. Any opening in a house is an open door to wildlife, Rastetter says. Raccoons will even tear out loose siding or rotting wood to get in, he says, so it's wise to inspect your house periodically and keep up with maintenance.
Chimneys are another common entry point, particularly for birds.
Nuisance-animal trapper Cathy Schultz recommends investing in a chimney cap to keep animals out. In fact, hardware cloth is a pretty handy material for animal-proofing many parts of the house, trappers say. Schultz also suggests nailing or stapling it securely over vent openings inside the attic and using it as a barrier beneath decks and raised sheds. Dig a trench around the perimeter of the building or deck, she says, staple or nail the hardware cloth to the base of the structure and extend the cloth down into the trench, bending it outward. Schultz says a trench 2 or 3 inches deep will work, although Miller recommends digging down about a foot.