Chirping noises, droppings, scratches on the walls, and stains at entries and exits are all signs that you have bats in your house or, more specifically, your attic. Because bats are nocturnal, there’s a chance that bats have already infested your home before you start to see warning signs, so don’t delay if you notice anything. If you see a bat or two at sunrise or sunset near your property, that’s another telltale sign that they could be setting up shop inside your space.

It can be difficult to know what type of animal is in your attic until you see it. But several clues can help you narrow down the suspects:

• Sounds: Smaller animals like rats and mice make scurrying and tapping/gnawing sounds. Larger animals like raccoons and opossums make louder clambering noises. Also, note when animals are noisy: Squirrels are active during the day, while rats are busiest at night.

• Droppings: Rats and mice leave small, rice-shaped droppings (the rat’s version is significantly larger). Bigger droppings belong to larger critters like raccoons. As long as you’re not squeamish, an image search can help you identify what you’re seeing in your attic.

When in doubt, take photos of damage or other evidence and show them to an experienced pest control pro.

When woodpeckers start banging on your walls or roof, they are probably looking for insects to eat, storing nuts for winter, drilling a hole to make a nest, or communicating with other birds to establish territory or find a mate.

The size of the hole can help determine the reason for the pecking. Small irregular holes are a result of insect hunts. Acorn holes are more consistently sized and often fitted with a nut in the middle. Nest holes are large and have rounded edges. If the bird is pecking to mark its territory or attract a mate, it may leave dents rather than holes, and the noise will stop when the mating season starts in spring.

Yes, professionals use humane and safe methods. Inform your provider of any specific concerns before treatment.