Animals That Nest in Walls

Rodents

• Deer and house mice are two mice species found in house walls, while roof and Norway rats also nest within the walls of households. These mammals enter wall interiors via small holes or cracks in the house's floors, walls and foundation. When nesting, mice and rats may have up to 84 offspring within a year. Food is the primary reason mice and rats enter household walls and lay nests. Traps and poisons are available for homeowners to remove rodents from their walls. According to Washington State University (wsu.edu), traps are preferable to poison since it kills rodents instantly; also, poison may accidentally harm children or pets if it is not properly used.

Carpenter Bees

• Carpenter bees receive their name from their proneness to develop nest sites within trees and wooden structures. A carpenter bee nest may be identified by circular holes or brown staining on the walls. First generations of carpenter bees cause more cosmetic damage than structural damage, according to Ohio State University (osu.edu). However, second and third carpenter bee generations may affect the integrity of a wall's structure. The university also says the most effective time to eliminate carpenter bee nests is during the evening, when the bees are not as active. Some preemptive measures to prevent carpenter bee nests are sealing any existing holes in the wall and use oil-based paint to ward off bees.

Birds

• According to the Massachusetts Audubon Society (massaudubon.org), house sparrows and European starlings are two bird species that often build their nests within house walls. These birds use dryer vents and holes to access the wall's interior. The primary months for house sparrows to develop a nest is April through September, while European starlings build nests from April to July. Twigs, leaves, dry grass and straw are some of the materials these birds use to construct their nest. The Audubon Society recommends waiting until the birds' offspring have left the nest before blocking the entrance or removing nests. Garden centers sell bird netting for homeowners who want to prevent birds from entering their walls.

Termites

• Termites are small insects who frequently nest in the walls with wooden infrastructures. The University of Kentucky (uky.edu) says termites cause billions of dollars of structural damage annually. Termites prefer warm temperatures and are most active from March to May. Most termite species live in the Southeast region of the United States. Homeowners may identify termite colonies in their house's walls by seeing mud tubes on the house's foundations. Also, the winged termites, known as "swarmers," will shed their wings; the shed wings are evidence of termite infestation. The university recommends hiring professional pest control companies to treat termite infestations.