Rodent Control in Champaign: Why Mice Come In and How Exclusion Works

Rodent control in Champaign gets busy every fall for a simple reason. The corn and soybean harvest clears the fields around town in September and October, and the first cold nights follow. House mice and deer mice lose their cover and food at the same time. The nearest warm building is often your garage or basement.

Why mice come in when they do

Mice do not move indoors at random. They follow warmth, food and shelter, and a house offers all three once nights fall near freezing. Homes on the edges of Champaign, Savoy and Mahomet that back onto fields usually see the first ones. Older homes near downtown see them too, because their foundations have more gaps.

A few mice can become a real problem fast. House mice breed all year once they are indoors, so a handful in October can turn into a colony by spring if nothing changes.

Signs you have mice

• Droppings about the size of a grain of rice along walls, in drawers and under sinks
• Chewed corners on cereal boxes, pet food and birdseed bags
• Scratching inside walls or ceilings at night
• Nests of shredded paper, fabric or insulation in quiet corners
• Greasy smudges along the paths they run

Larger droppings, burrows beside the foundation and gnawed wood point to Norway rats. They are common near grain storage and farm buildings around the county.

How mice get in

A house mouse can squeeze through a gap about the width of a pencil. Gaps most people never notice are wide enough. These are the usual entry points in Champaign homes:

• Gaps where gas, water and cable lines enter the house
• Dryer vents and bath fan vents without a working flap
• The bottom corners of garage doors
• Cracks in older brick or block foundations
• Spaces where siding meets the foundation
• Crawl space vents and doors that do not close tight

How exclusion works

Exclusion means sealing the gaps so new mice cannot get in. Traps alone clear the mice inside, but more keep arriving through the same holes. Sealing first, then trapping, ends the cycle.

The technician walks the outside of the house at ground level and along the roof line, then checks the basement, crawl space and garage from inside. Each gap gets a material mice cannot chew through. Steel wool or copper mesh fills small gaps around pipes, with sealant over it. Hardware cloth covers larger vents. Metal flashing or a new door sweep closes gaps at the garage door. Expanding foam alone does not stop mice, because they chew right through it.

Once the house is sealed, traps go along the inside walls where mice travel. Return visits clear the traps and check whether any new gap has opened.

What rodent control costs

HomeGuide's national cost data puts mouse extermination at $150 to $550, depending on the method and how many mice there are. HomeGuide lists rodent cleanup at $600 to $1,000 when droppings and nests need removal. The number of gaps to seal, access to the crawl space and the number of return visits move the price. The technician writes the price down after the inspection.

Cleaning up safely

Deer mice, common near fields and sheds, can carry hantavirus. The CDC advises airing out closed spaces for at least 30 minutes before cleaning. Wear rubber gloves and spray droppings with disinfectant or a bleach solution until they are soaked. Wipe them up with paper towels. Do not sweep or vacuum droppings, which can stir the virus into the air.

What you can do before fall

• Store birdseed, grass seed, pet food and pantry goods in sealed metal or hard plastic bins
• Stack firewood away from the house
• Trim shrubs back from the siding
• Check the garage door seal in September

If you already see droppings, rodent control works best before the colony grows. Summer brings a different pest, and mosquito yard treatment covers what spraying can and cannot do.