People often ask when rodent season begins. The honest answer is that it creeps in. As nights get cooler, as rain sets in and as outdoor food runs short, animals that lived in the yard all summer start testing buildings. This guide breaks that drift into stages so you can match your effort to the calendar.
Late summer: the quiet window.
This is the best time to work, because you can see gaps in dry light and repairs are easy. Walk the outside of the house and look at the places where animals enter: vents, garage seals, pipe collars, roofline gaps and crawl space screens. A mouse needs only a gap about the width of a pencil.
Use this window to move firewood away from the wall, cut back plants that touch the siding and store pet food in a lidded bin. These steps cost almost nothing and reduce the pull toward the house.
Early autumn: the first cool nights.
When the first cold nights arrive, animals begin to look for warmth. Garages, sheds and outbuildings feel it first, since they are closest to the yard. Check these spaces for droppings, shredded paper or chewed bags, and look under stored items.
| Stage. | What happens. | What to do. |
|---|---|---|
| Late summer. | Animals stay outdoors and gaps are easy to see. | Inspect and seal, move wood and tidy edges. |
| Early autumn. | Cool nights send animals toward outbuildings. | Check garage and shed, clear stored boxes. |
| First heavy rains. | Burrows flood and food scatters. | Walk the lot after storms and clear debris. |
| Early winter. | Animals reach the house itself. | Listen at night and check attic and pantry. |
| Deep winter. | Established nests and breeding indoors. | Call for inspection and sealing. |
First heavy rains.
Heavy rain moves things. Burrows flood, leaf litter soaks and seeds wash into piles. An animal that has just lost its shelter will look for another, so the days after a storm are the ones when new activity shows up at the wall.
Walk the lot the morning after. Look for fresh soil at the base of the foundation, new holes beside vents and wet cardboard near the door. If you find a burrow, photograph it and call before you fill it.
Scratching after midnight can be reported after midnight, since somebody picks up the phone at every hour.
Dial (888) 686-4821Early winter: inside the walls.
By early winter, an animal that found a gap may already be in the attic, a wall or the crawl space. The signs are subtle at first: a faint scratching at dusk, a few droppings in a kitchen drawer or the smell of a closed room. Do not wait for these to become loud.
- Listen in the evening and just before dawn, when animals are most active.
- Check the back of kitchen cabinets and the space under the sink.
- Look at the attic hatch and the crawl space door.
- Inspect stored dry goods for gnawed corners.
Deep winter: nests and breeding.
Mice and rats can keep breeding through winter, because a warm house supplies shelter and food, and a few animals may become many by spring. If sign is already present, the useful steps are removal first and sealing second.
The mouse control and rat control pages describe what each visit includes. Exclusion closes the gaps, and the inspection comes first when you are not sure what you have.
Spring: finding out what winter did.
Spring is a good time to look for what the season left. Check the attic for matted insulation and droppings, and the crawl space for nests. If you find soiled areas, do not sweep. Follow our guide to safe cleanup of droppings and call if the area is large.
The aim of the whole timeline is simple. Seal in summer, watch in autumn, act early in winter and clean in spring.
How to treat rodent waste without raising dust
Nothing here is particular to our visits. Any health agency would tell you the same before you start picking things up.
- Dry sweeping is the common error: it makes old waste airborne and easy to inhale.
- Let air move through a stale crawl space or storage room for about thirty minutes before you begin.
- Use gloves for the entire task and wash your hands thoroughly after.
- Soak droppings and the surface beneath them with disinfectant or a label-directed bleach mix, wait about five minutes, then wipe up with paper towels.
- Wipes and droppings go in a bag that is closed tight, and carcasses stay off bare skin.
- How risky an exposure was is a doctor's call. Go if fever, aches or labored breathing develop.
Public guidelines behind this advice
Public documents sit behind the advice above. They set out general practice and rules, and none of them endorses us.
- CDC page on hantavirus prevention: Reducing exposure in houses, sheds and vehicles through practical steps from the CDC's hantavirus page.
- CDC page on rodent cleanup: Cleanup guidance explaining why sweeping or vacuuming dry waste is advised against.