The Sounds In Your Walls And Attic Might Be Rodents
Rodents are often quite busy at night. If you are hearing noises at night in your attic or in your wall, you likely have a nocturnal creature living or trapped there. The most common would be mice, rats, and bats.
Rats
Rats can get trapped in your wall voids, or nest in your attic. They will bump, scratch and thump as they maneuver their way up and down your walls and around your attic.
Bats
Bats are usually much quieter, unless you have several.
Mice
With mice, you will probably hear a scampering noise, notice nests or gnaw holes, and probably see droppings.