Female squirrels use numerous materials to build a nest, including trash, paper, plastic, sticks and insulation. A quick way to know if there is a squirrel in your attic is to look for fecal droppings. If you see nesting materials in the insulation or near your vents, there are most likely babies nearby. Baby squirrels can often be heard crying and crawling around in the ceiling.
Squirrels are wonderful mothers, but they tend to choose nesting materials that can be flammable, such as wood, leaves, pine needles, feathers and even man-made materials such as plastic. These nesting materials pose a threat because they could easily catch fire. And if the materials are near wiring, they must be removed immediately. Squirrels will chew through almost anything, and one of their favorite things to chew is wiring. If a squirrel chews into the electrical wires, this could easily start a fire.