Rodent Control

Mice or rats changes the plan

A house mouse gets through a gap of about a quarter of an inch — a hole the width of a pencil is enough — and stays close to home, usually within a room or two of the nest. Rats need a larger opening but travel much further and are far more wary of anything new, which is why a rat job takes longer to get right.

Droppings tell you which. Mouse droppings are about a quarter of an inch and pointed at the ends; rat droppings are half an inch or more and blunt. Mice are curious about a new trap. Rats avoid it for days.

Exclusion is the actual work

Trapping without sealing is a subscription. The gaps are the same few places in most houses: where the water line and the gas line come through the wall, the gap behind a dryer vent, the corner of a garage door seal, a soffit that has pulled away, the space where a deck ledger meets the siding.

A technician goes round the outside with a flashlight before setting anything inside. Steel wool and foam are a stopgap; sheet metal, hardware cloth and mortar are the repair.

Poison is not the default answer

Bait placed indoors kills the animal wherever it happens to be, which is often inside a wall or under a floor, and the smell lasts weeks. It also carries a risk to pets and to whatever eats the carcass outside.

Ask what is being placed, where, and in what kind of station. A technician who cannot answer that in plain words is worth a second opinion.

What to say when you call

• Where you found droppings, and how big they are.
• Whether you hear scratching, and whether it is in a wall, a ceiling or under the floor.
• Whether anything has been gnawed — packaging, wiring, the corner of a door.
• Whether there is a crawl space or an attic, and whether it can be reached.