Like humans, critters prefer to stay warm and protected from the elements during cold weather. Attics and crawlspaces provide wildlife with warmth, nesting materials, and safety they need to survive during cold temperatures.
The most common pests we see moving indoors during the colder months are squirrels, rats/mice, raccoons, and opossums. It’s important none of these animals hibernate. So if they are in your home to escape the cold weather, they’ll continue to be a nuisance.