Many rodent problems begin outside before activity is noticed indoors. Overgrown shrubs, trees touching the roofline, thick ground cover, block walls, garages, sheds, and attic spaces can all create opportunities for rodents to move, hide, and settle in. Roof rats are especially common in Las Vegas because they are strong climbers and can use trees, walls, utility lines, and roof edges to reach protected areas.
Once rodents find a weak point, they do not need a large opening to create a problem. Small gaps around rooflines, vents, garage doors, utility openings, and construction seams can be enough for mice or rats to investigate, squeeze through, or chew open further. Because rodents can gnaw through many common building materials, a small vulnerability can turn into an active infestation if the source of the activity is not addressed.