Why Rodents Enter Homes in Winter (and How to Stop Them at the Door)

Every year, the week after Central Texas's first real cold front, our phones light up with the same report: scratching in the attic, droppings in the pantry, something scurrying behind the dishwasher. It's not a coincidence — it's biology on a schedule.

Rodents don't hibernate. When temperatures drop, their outdoor food supply collapses at exactly the moment their bodies need more calories to stay warm. A heated structure with stored food isn't just attractive; it's survival.

How They Actually Get In

A mouse fits through a gap the width of a pencil (about 1/4 inch); a rat needs only a quarter-sized hole. The most common winter entry points we document are garage door corner gaps, gaps around A/C line penetrations, unscreened weep holes, roof returns where fascia meets shingles, and dryer vents with broken flaps.

Roof rats — the dominant species in tree-heavy Austin neighborhoods — enter high, traveling branches to the roofline. If you hear noise above the ceiling rather than in the walls, think roof, not foundation.

Why Traps Alone Don't Work

Trapping removes individuals; it doesn't remove the opening, the scent trail marking it, or the conditions that attracted rodents in the first place. As long as the doorway stays open, winter replaces every rodent you remove.

Real winter rodent control is exclusion: sealing every entry point with materials rodents can't chew — steel mesh, hardware cloth, metal flashing — after removing the animals currently inside. Done properly, it's a permanent fix, not a subscription to trap-checking.

Your Pre-Winter Checklist

Before the first November front, walk your home's perimeter and check these:

• Garage door seals — daylight at the corners means mouse access
• Door sweeps on all exterior doors
• Gaps where cables, pipes, and A/C lines enter walls
• Tree limbs within 6 feet of the roofline (trim them)
• Pet food and bird seed stored in chew-proof containers
• Firewood stacked away from the house and off the ground

Already Hearing Noises?

Act quickly — a pair of mice becomes a colony in weeks, and rodents gnaw wiring year-round. A professional inspection maps every entry point and quantifies the population, and combined trapping-plus-exclusion typically reaches zero activity within two to three weeks. GreenShield's rodent exclusion work is warrantied, because sealed correctly means sealed for good.