Information on rats and mice can also be seen on the Healthy Canadians website.
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.
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 the 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.
Mice and rats are carriers of disease, and can damage property. The deer mouse is the most common carrier of the deadly Hantavirus.
Prevention is key in controlling rats and mice problems in the 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.
There are several types of traps that can be used to control rats and mice. Follow the manufacturer's directions on how to use a particular trap.
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 these general guidelines:
**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. Therefore, it is recommended that ultrasonic devices be used along with other pest management practices.
Poisoned baits are a common way of controlling rodents. Follow the directions for use closely. Baits or poisons cannot replace rat and mouse-proofing.
Anticoagulant rodenticides inhibit the clotting of blood. These products are sold as liquids or powders to mix with seed, paraffin blocks, bait packages or loose pre-mixed bait. Products available to the general public may contain the active ingredients warfarin, diphacinone, chlorophacinone or bromadiolone. Note : anticoagulants are usually highly toxic.
Non anticoagulant poisons available to the general public may include the active ingredient cellulose from powdered corn cobs. Some anticoagulant and non-anticoagulant rodenticides are sold as commercial class products and must be applied by a certified professional.
Repellents containing thiram have also been found effective in discouraging mice from damaging young trees and ornamentals.
Use caution when near urine and droppings: