Rodent Signs in a House, and When to Call

The kitchen and the pantry

In the kitchen, rodent signs are droppings in cupboards, gnaw marks on food packets and the smell of urine in a corner. A pantry is the most likely place for a mouse to start.

Look along the back of the cupboards, under the sink and behind the fridge and the stove. Dark, rod-shaped droppings are a sign of mice. Larger droppings usually mean rats. Gnaw marks on cereal packets and bread bags show that the animal has found food and is returning to it.

A pet that stares at a cupboard or a wall, or a smell of urine in a corner, is a sign to look harder. Note the place and the time, and bag any food that is open.

• Droppings along the back of cupboards and under the sink
• Gnaw marks on food packets, bread bags and cereal boxes
• A urine smell in a corner or under a shelf

The garage and the outbuildings

The garage is the most common entry point for rodents in a house, because it has gaps at the door, the vents and the utility lines. Rub marks and droppings along the wall are the signs to look for.

Check the seal at the bottom of the garage door, the vent screen and the place where a utility line enters the wall. A gap the width of a coin is enough for a mouse, and a rat can use a gap the size of a finger. Greasy rub marks along a wall or a pipe show the route the animal travels.

Look at stored boxes and bags of feed or pet food. A chewed bag and a scattering of droppings are a clear sign that the stock is being used.

• The garage door seal and vents
• Rub marks along walls and pipes
• Chewed bags of food or feed

The attic and the roof space

In the attic, rodent signs are scratching or running in the insulation at night, droppings on the boards and nesting material. The attic is often where a rodent population becomes established.

Listen after dark. A scratching or running sound in the wall or the ceiling is a sign of activity, and a sound that comes and goes at the same time each night suggests a route the animal uses regularly. Check the boards and the insulation for droppings, and look for shredded material near the eaves.

Do not go into the attic if the boards are weak or the insulation is wet. Describe what you see on the call and let the technician plan the access.

• Scratching or running sounds at night
• Droppings on the boards and insulation
• Shredded nesting material near the eaves

The crawl space or the cellar

Under the floor, rodent signs include droppings on the joists, tracks in the dust and a smell of damp or nesting. The entry is often at a vent or where a pipe enters the foundation wall.

Check the vents and the openings around pipes and wires. A gap at the foundation wall is a route in, and the technician will look for it on the visit. Note any standing water or damp soil, since a damp crawl draws insects and makes the space attractive to animals.

Do not enter a crawl or cellar that has standing water, exposed wiring or a damaged floor. Tell the technician what is there and where the access is.

• Droppings on joists and dust tracks
• Gaps at vents and at pipes through the foundation
• Standing water or damp soil noted

The point at which to call

Call the line when the signs are in a food area, when they are spreading to more rooms, when a pet or a child is affected, or when the signs have not changed after a week of waiting. Those are the points at which waiting makes the problem larger.

A single old dropping in the garage is not an emergency, but it is a reason to look for the gap. Activity in the kitchen, in the food store or near a child's bedding should be reported at once, and the line sorts those calls first.

If you have set traps and caught nothing for a week, the problem is probably the entry, not the trap. Call the line and ask for an exclusion check, which finds the gap before more traps are set.

• Call at once: activity in a food area or near a child
• Call soon: signs in more than one room, or a pet affected
• Call after a week: no change in the signs, or traps with no catch

Signs that are not rodents

Some signs look like rodent activity but come from other causes, such as a wild bird in a vent, a loose cable tapping on a wall or a damp stain. Checking for them first saves a visit and a trap.

A scratching sound in the ceiling in the early morning can be a bird that has entered a vent or a gap under the roof. Look for feathers and droppings with a different shape and size, and for a fresh opening at a vent or a soffit. A tapping or rattling in the wall at a regular time may be a loose cable or a pipe that expands as the water heats.

A dark stain on a ceiling or a wall is usually moisture, and it is a reason to check for a leak rather than for an animal. Where the signs are unclear, describe them on the call, and let the technician decide which cause to check first on the visit.

What the technician does on the visit

The technician confirms the animal from its signs, traces the route, finds the entry gaps and then sets the traps and the sealing plan. The order keeps the traps where the animal goes and the household's time on the gaps that matter.

On arrival the technician asks where the signs were first seen, when they changed and whether any trap was set. The answers shape the walk. The technician then checks the foundation, the vents, the eaves, the garage and the utility lines, and marks each gap on the sketch.

Traps are set along the walls where the droppings and rub marks show the animals travel, and each one is numbered on the plan. Sealing is explained before it is done, and the household decides which gaps are closed on the day. The follow-up checks the traps and the gaps, and the record shows the catch and the openings still open.

Keeping the signs from coming back

Once the animals are removed and the entry gaps are sealed, the household's habits decide whether the problem returns. Food, clutter and standing water are the three things to control.

Store all food in sealed containers, including pet food and birdseed, and wipe up crumbs and spills the same day. A rodent that finds food in a cupboard or a garage will come back for it, and a sealed container is cheaper than another visit. Keep the bins outside lidded and away from the walls of the house.

Remove clutter from the garage, the shed and the attic. Stacked boxes, old newspaper and piled clothes give a rodent nest material and shelter out of sight. Store items on shelves off the floor, and keep the stored wood away from the house. Dripping outside taps and gutters that overflow hold water that draws other animals close to the walls, so note them for the next visit.

Sealing materials and what they are for

The right material depends on the size and the place of the gap. Using the wrong one wastes the visit, because an animal can chew through a soft filler or push past a loose mesh.

Small gaps around pipes and cables are usually sealed with steel wool packed in first, then a sealant over it, because a rodent chews through soft material but not through packed steel. Larger openings at a vent, a soffit or a gap under a door are closed with metal mesh fixed firmly to the framing, since foam alone is easily gnawed. A door sweep or a new seal at the bottom of a garage door closes the gap that most often lets animals in.

The technician chooses the material on the day and explains the choice. A household should not seal a gap with a material it has picked up at a shop without asking, since the wrong filler can trap an animal inside a wall, which creates a new problem and a smell.