Nobody calls us about mice in August. Everybody calls us about mice in late October.
That two-month gap is the whole problem, because the work that actually ends a rodent problem is sealing the building — and sealing the building is much easier and much cheaper before the animals are inside it.
The seasonal picture in Simcoe County
Field mouse populations build through the summer. Two things then push them toward heated structures:
Cold. The first sustained cold is the main driver. In most years that means October into November.
Loss of cover. On a farmland edge, harvest removes food and shelter over a matter of days, and that pulse can arrive earlier than the cold does. Properties backing onto fields around Stroud, Angus and the Springwater and Oro-Medonte edges tend to see it first.
Once they are in, they are in a heated, sheltered space with no reason to leave. This is why “they went away in the spring” is usually wrong — the activity became quieter, not absent.
Why baiting alone keeps you on an annual contract
Killing the mice in the house does nothing about the gap they used to get in.
That is the whole argument for exclusion-first, and it is worth being blunt about the economics: a treatment-only approach means you pay again next autumn, and the autumn after. It is a good business model. It is not a good outcome for you.
A proper exclusion is a survey of the building envelope followed by sealing every viable entry, in materials that a rodent cannot chew back through. Then, and only then, does dealing with whatever is already inside make sense.
Where they actually get in
Almost never through a dramatic hole. The entries we seal are mundane:
- Utility penetrations — where the gas line, the AC line set, the hose bib or the electrical service passes through the wall. These are the single most common entry.
- Garage door corners. The bottom seal never quite meets the frame at the corners. A garage is also a heated-adjacent space full of stored food.
- Weeping holes and gaps under siding, particularly where a deck or a step has settled against the wall.
- Where a dryer vent or bathroom vent exits, especially when the flap has broken.
- The sill plate line, where the frame meets the foundation, on older houses that have moved.
A mouse gets through a gap about the width of a pencil. If you can push a pencil into it, seal it.
The cottage and seasonal-property version
Innisfil’s shoreline empties for the winter, and an unoccupied house is more attractive to rodents than an occupied one, not less. Nobody is disturbing them and nobody notices for six months.
If you close a property for the season, exclusion before you leave is worth several times what it costs. The alternative is discovering the damage in May, and rodent damage over one winter in an unoccupied building is a different order of problem — insulation, wiring and stored contents.
The timing, plainly
August and early September is the window. The building is dry, the work can be done on a normal schedule, and it happens before the pressure arrives rather than during it.
By the time you hear scratching behind the stove, you are buying the same work plus a treatment, and doing it in worse weather.