HealthLink BC File #37, February 2011

Getting Rid of Rats and Mice

• What harm can rats and mice cause?
• Is it easy to find rats and mice?
• How can I get rid of rodents?
• How can I prevent rodents from living on my property?
• What about using poison?

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Although there are more than 20 types of rodents in British Columbia, only 3 types cause common domestic or farmyard problems. The 3 species most likely to invade a home or farm outbuildings are the house mouse, the Norway rat, and the black rat.

What harm can rats and mice cause?

Rats and mice can pose a threat to health and property. They cause damage to buildings by chewing on insulation, sidings, and wallboard. They also eat a variety of stored food. These rodents often contaminate food that they do not eat, which can lead to food poisoning.

All 3 types of rodents can also spread diseases, which are carried on their feet. Diseases can be spread by their bite, urine, or droppings. The ticks and fleas carried by rodents can also spread diseases. For more information, see HealthLink BC File #01 Tick Bites and Disease.

Is it easy to find rats and mice?

Rats and mice are easy to detect and leave plenty of evidence. They chew cereal boxes or dried foods in plastic bags, leaving a mess. Chewing marks on woodwork and plumbing pipes are other signs of a rodent infestation. Dark brown droppings are also commonly found where rodents eat and in other areas. Rats and mice often hide in between walls and in the ground under sheds, garages, and foundations. . It is possible to hear them moving around or even chewing when your house is quiet.

How can I get rid of rodents?

How can I get rid of rodents? Rats and mice have babies often, so it is important to find and get rid of them. Even if you do not see an actual rodent, the size of the droppings can tell you if there is a mouse or rat. Mouse droppings are approximately 6.35 mm (1/4 inch) long, and rat droppings measure up to 19.05 mm (3/4 inch) long.

The best way to get rid of rats or mice is by using traps. Buy several of the appropriate snap traps and bait them with dried fruit, peanut butter mixed with oats, or cheese. Be sure that the bait is securely attached to the trip pedal; otherwise the trap may not spring when the food is removed.

Set the traps at right angles to the walls where the rodents are known to travel, with the bait side of the trap toward the wall. Wear gloves or use a plastic bag for disposing of the trapped rodent, which should be wrapped in plastic and placed in the garbage.

How can I prevent rodents from living on my property?

There are steps you can take to prevent rodents on your property.

1. Eliminate food and water sources:

• Keep all garbage in metal containers with tight fitting lids.
• Compost kitchen waste in rodent-resistant containers. Do not throw meat, bones, grease, fish or other food scraps into the compost.
• Ensure the compost is away from the house. Properly maintain the compost by stirring and adding lime every few months.
• Remove fallen fruit and nuts from your yard.
• Remove pet food right after feeding and do not leave it outside overnight. Clean out waste and food from pet pens and enclosures.
• Equip bird feeders with trays and clean spilled seeds often.
• Repair any plumbing leaks to remove collected water. Cover pools and whirlpools when not in use.

2. Eliminate hiding and living places:

• Do not plant shrubs or flowers close to buildings. Keep a space clear between buildings and plants and allow 15 cm to 20 cm (6 to 8 inches) under plants. Trim grass and ditch areas.
• Remove unused piles of lumber, old sheds, or buildings.
• Do not store old cars or furniture outside.
• Store lumber and firewood on stands 30 cm to 45 cm (12 to 18 inches) off the ground.

3. Protect buildings:

• Cover crawl spaces, fresh air and attic vents with 6.35 mm (1/4 inch) metal screening or steel mesh.
• Repair cracks in cement footings and foundations.
• Build sheds on concrete slabs.
• Install 6.35 mm (1/4 inch) hardware cloth inside your compost.

What about using poison?

It is not a good idea to use poison or baits to control rodents. Poisoned rodents can crawl away and die, and their bodies can be hard to find and breeding grounds for disease. Poisons can also accidentally harm pets, wild animals, or even children.

Ultrasound repellers, although initially effective, are expensive and do not have long-term success at eliminating rodents.

After trying preventive measures, if a pest problem still exists on your property and you want to try rat poison, there are certain things you should consider:

• Set out non-poisoned food for a few days prior to baiting, so the rodent starts feeding in the area.
• Read and follow the directions on the label carefully.
• Set bait in areas where there is no access to children or pets.
• If there are children or pets around, place baits in protected and locked boxes.
• Place bait deep in burrows, tunnels or holes.
• Change bait frequently and before it starts to smell.
• Remove dead rodents and all baits once pest control has been completed.

If you are unable to remove the rodents on your own, contact a licensed company with certified staff to help you.

For more information

For more information, please visit the BC Ministry of Environment website at www.gov.bc.ca/env/, or contact your local environmental health officer.

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