The scratching sounds in walls reach their peak during this season as rodents seek shelter from cooling temperatures. These pests create more than just noise – they pose serious risks to property and peace of mind.
Hannu Heinänen, a professional pest control expert, explains that rodent season hits its worst point during this period. 'When rodents have direct access to bird feeders or spilled grains on the ground, more and more appear in the area,' he said. 'They move indoors when temperatures drop and natural food sources diminish.'
Rodents typically need food, shelter, and water to survive. Mice can obtain sufficient moisture from their food alone. They most commonly enter buildings through ventilation gaps in exterior cladding. From there, they move between walls according to their needs.
The scratching sounds might seem like the main concern, but Heinänen identifies greater problems. 'Rodents must constantly gnaw to control their teeth growth. One rat can urinate five liters per year, and there's never just one,' he explained. 'I know cases where mice have chewed holes in sauna moisture barriers, allowing steam into structures and causing major damage.'
Electrical wiring presents another danger. Mice enjoy chewing on cables, creating fire hazards throughout homes. Beyond physical damage, the psychological impact affects residents. 'People feel terrible,' Heinänen noted. 'The scratching keeps them awake, stress increases, and some become hysterical thinking about what's happening inside their walls.'
Prevention offers the best defense against pests. Heinänen recommends installing protective netting during construction phases. 'It increases costs initially, but solving problems later proves much more expensive,' he stated. Buildings should not have vegetation attached, tree branches shouldn't reach roofs, and all potential entry points should be netted.
Homeowners can improve their situation independently. They can net openings and acquire various mouse and rat traps. 'For trap bait, I recommend peanut butter because it's sticky and nutritious,' Heinänen suggested. 'Hard baits like cheese pieces can detach easily, allowing mice to steal them without triggering the trap.'
Place traps along rodent pathways since the creatures always seek shelter in dark places. When pest problems grow too large, professionals become necessary. 'Experts know where to search for pests and how control works best,' Heinänen explained. Carefulness serves as one of their most important tools.
Professional pest control isn't free, but it usually costs considerably less than repairing damage caused by pests. The solution requires finding every possible entry point, pathway, and optimal control method for each location and pest type.
In one household, initial measures included removing all open dog treat bags from tables and cabinets, transferring human food to sealed containers, and adding lids to biowaste bins. These actions stopped the scratching temporarily. The recent addition of a cat has caught several mice, though rodents still appear occasionally.
This seasonal pattern reflects broader Nordic housing challenges where older wooden structures provide easy access for wildlife. The problem intensifies during colder months across Finland, Sweden, Norway, and Denmark as animals seek warmth. International residents often underestimate how destructive small rodents can become in Scandinavian climates where buildings require tight insulation against harsh winters.
Property damage from Nordic rodent infestations typically involves both structural and electrical systems. Insurance companies in the region report increased claims during autumn months when animals become most active indoors. The situation demonstrates how climate and architecture create unique pest control challenges across Northern Europe.