Common signs of a rodent infestation include the actual sighting of live or dead rodents, droppings, gnaw marks, rub marks, gnawed fruit in trees, and scratching sounds at night. Look for gnaw marks on door corners, walls, and baseboards. Rat droppings are shiny black and ½ to ¾” long, and mice droppings are smaller with pointed ends. Burrows outdoors along foundation and walls or beneath debris or shrubbery are obvious signs of a Norway rat infestation.