Rats and mice
What are they?
The house mouse has large ears and is light brown to dark grey, with a lighter colour on its belly. It is often found in urban areas. The deer mouse is brown or grey with a white belly and feet. The white colour on the underside of its tail is an easy way to spot a deer mouse. It may invade buildings near fields and woodlands in the fall.
A rat is larger than a mouse and can weigh up to 0.5 kilograms (1 pound). The Norway rat and the roof rat look similar, but their habits are different. The Norway rat builds elaborate systems of tunnels and burrows at ground level. It prefers damp areas like crawl spaces or building perimeters. The roof rat is an agile climber and prefers to live in trees, vines, and other dense vegetation. It will infest attics, rafters, or roofs, and upper stories of buildings.
Knowing the type of pest you have can help you figure out the best approach to controlling them. (For example, a rat trap is too large to kill a mouse.)
Should I be concerned?
Mice and rats are carriers of disease, and can damage property. The deer mouse is the most common carrier of the deadly hantavirus.
How do I know if I have a problem?
Scampering and scratching sounds in the walls of your home at night, signs of gnawing or chewing, or damaged food packages can mean you have an infestation of mice or rats. Other signs include droppings and urine, burrows or holes in and around foundation walls, or tracks on dusty surfaces.
Mice and rats are prolific breeders. Tackle the problem of occasional invaders right away to avoid a severe infestation.
How can I get rid of rats and mice?
Prevention is key in controlling rats and mice problems in your home.
Rodent-proof your home
The first line of defence is to get rid of easy entry points. Mice can squeeze through cracks as small as a dime, while rats can enter through a quarter-sized hole. Even the small gaps created by worn thresholds under doors will allow mice access to your home.
- Use metal weather stripping under doors, and weather strip windows.
- Patch cracks in foundations.
- Stuff steel wool around pipes before caulking or plastering.
- Cover dryer vents, attic vents, and soffits with fine mesh metal screening.
Make your home less appealing to rodents
- Remove cosy nesting sites in unused clutter around your house and garage.
- Cut tall grass and weeds back from your house.
- Secure garbage in containers with tight-fitting lids.
- Raise woodpiles about 30 centimetres (1 foot) off the ground. Place them away from your house.
- Never place fatty or oily food waste, eggs, or milk products in the composter.
- Use a layer of heavy metal mesh between the soil and the bottom of the composter.
- Eliminate water sources (like leaky taps, sweating pipes, and open drains).
- Keep your kitchen clean. Store dry food and dry pet food in metal or glass containers.
Physical control options
If you already have rats or mice in your home, there are several options for control.
There are several types of traps that can be used to control rats and mice. Snap traps and electronic traps are easy to use and very effective if well positioned and set properly. They generally kill rats and mice instantly. Live traps have trap doors that are triggered when rats or mice walk over them.
Follow the manufacturer's directions on how to use a particular trap. These are general guidelines:
- Most traps without covers should be set at right angles to the wall, with the baited end of the trap closest to the wall. Some traps (like electronic traps and covered snap traps) should be set with the entrance parallel and flush against the wall. Set 1 trap per metre (yard) along walls, or 5 to 10 traps per visible mouse hole.
- Allow a warm-up period of 3 to 4 days (bait the traps but do not set them), so that the rats or mice become comfortable taking the bait.
- Use baits of strong-smelling, sticky foods like peanut butter, bacon grease mixed with oats, raisins, or gumdrops.
- Reuse the traps: they are more attractive to rats and mice.
- Move traps to different locations if the bait does not disappear regularly.
- Reset the traps in 2 to 3 weeks to catch maturing rats and mice.
- Glue traps are also available and can be used with or without bait.
Note: It is important to check all types of traps daily.
Ultrasonic devices give off sound waves or vibrations that rats and mice dislike. Rats and mice may, however, adapt to the devices and return. It is recommended that ultrasonic devices be used along with other pest control options.
If you use a pesticide to control your pest problem, read the label to make sure you are choosing the right product for the right pest. Follow all label directions and warnings carefully. Always look for a Pest Control Products (PCP) number on the label so you know the product has been approved by Health Canada. See Use pesticides safely for more information on using pesticides safely.
Baits or poisons should not be used as the only method to control rats and mice. Other management strategies such as rat and mouse-proofing and good sanitation must be used to achieve satisfactory control of rats and mice.
- Poisoned baits are a common way of controlling rodents; they must be used with a tamper-proof bait station in areas accessible to children and pets. Read the product label and follow the label directions and safety precautions closely.
- Anticoagulant rodenticides prevent the clotting of blood. These products are sold to the general public in a solid form such as a paraffin block. Note: Anticoagulants are usually highly toxic. Keep away from children and pets.
- Other products containing non-anticoagulant poisons available to the general public include the active ingredients cellulose from powdered corn cobs and bromethalin.
- Commercial class products must be applied by a certified professional. Commercial applicators have access to other bait types such as loose pre-mixed bait.
- Repellents may also be used to discourage rats and mice from damaging young trees and ornamentals, structures, and garbage bags.
Use caution when near urine and droppings:
- Wear rubber gloves and a dust mask during cleanup.
- Dampen droppings and debris with a solution of bleach and water before wiping up.
- Wear gloves to dispose of dead rats and mice.
- Double bag the bodies of dead rats and mice in plastic bags and put in a garbage bin with a secure lid.
- Wash hands and exposed clothing thoroughly after clean-up, and separate from other laundry.
- Never sweep or vacuum dry droppings. The dust that is raised can cause illness.
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