House Mouse — Identification & Control

A female house mouse can produce five to ten litters per year, each of five to seven pups, and those pups reach breeding age in six to eight weeks. Indoors, with climate control and steady food, reproduction is continuous — there is no winter slowdown. That compounds fast. It is why a homeowner who first hears scratching in October can be dealing with dozens of mice by February.

They are also highly mobile and neophobic — cautious around new objects in their environment — which is why professional trap and bait placement matters more than quantity. A properly placed pair of traps in the right runway will out-catch a scattered dozen in bad spots.

An adult house mouse can squeeze through any opening a #2 pencil can pass through — roughly a quarter of an inch. That means the entry points people expect (obvious holes, unsealed doors) are only the beginning. In a typical Triangle home the real entry points are:

• Gaps around plumbing and utility penetrations under sinks and behind washing machines.
• Unsealed gaps where the sill plate meets the foundation.
• Gaps around dryer vents, HVAC line sets, and gas-line penetrations.
• Damaged crawl-space vents and vapor barriers.
• Garage-door corner seals that no longer meet the concrete.
• Roof-line gaps at soffit corners and fascia returns.

Any effective rodent job in the Triangle includes a full exclusion inspection, not just trap placement.

• Droppings — dark rice-grain-shaped, 3-6 mm, often concentrated along walls, in pantries, in silverware drawers, and behind the stove.
• Chew marks on cardboard, plastic packaging, wood trim, and — most dangerously — electrical wiring.
• Scratching or scampering sounds in ceilings, walls, and attics, especially just after dark.
• Grease marks (rub marks) — dark smudges along baseboards where mice repeatedly follow the same path.
• Urine smell — a distinct musky odor in heavy infestations, especially in cabinets.
• Nests — shredded insulation, fabric, and paper tucked into wall voids, drawers, or appliance motor housings.

House mice are documented carriers of salmonella, hantavirus, lymphocytic choriomeningitis (LCMV), and leptospirosis, and they mechanically spread contamination through droppings and urine across pantries and food-prep surfaces. The property-damage side is just as real: chewed insulation loses R-value; chewed wiring is one of the most cited causes of otherwise-unexplained house fires; and chewed HVAC ducts, plumbing insulation, and drywall corners add up to repair bills that dwarf the cost of professional rodent control.

This is why we treat rodent work as both a health and a structural service — not a nuisance call.

Castle's rodent program is built around exclusion first — because trapping without sealing entry points is a treadmill. A typical plan includes:

• Whole-home inspection — attic, crawl space, garage, plumbing penetrations, roofline, and foundation perimeter — to identify every likely entry.
• Exclusion work — sealing gaps with rodent-resistant materials (copper mesh, hardware cloth, sealants rated for gnawing) so new mice cannot replace the ones we remove.
• Interior trapping placed in actual runways along walls and behind appliances — not the middle of a room where mice do not travel.
• Exterior tamper-resistant bait stations around the perimeter to intercept mice before they enter.
• Follow-up service until sightings and evidence stop, then transition to ongoing monitoring.

Every plan is scoped and priced with a personalized quote based on the home's size, construction, and current rodent pressure.

• Seal any gap wider than a quarter-inch around plumbing, utility, and HVAC penetrations.
• Replace worn garage-door corner seals — one of the top entry points we find.
• Keep garage-stored pet food, birdseed, and grass seed in hard-sided sealed containers, never in the bag.
• Store firewood off the ground and at least twenty feet from the house.
• Trim tree limbs back so branches do not touch the roof or gutters.
• Keep the kitchen tight overnight — crumbs, cereal spills, uncovered fruit.
• Do not rely on cats. Cats catch some mice; they do not eliminate infestations.