Two species of rats (Norway and roof rats) and one species of mouse (house mouse) are the most common pest rodents in suburban areas. The three species have different behaviors and nesting characteristics so it is important to know which species you are dealing with in order to properly control an infestation. Learn more about rodent identification.
Improving sanitation and blocking entry points and hiding spaces are essential to increasing the effectiveness of the controls and preventing re-infestations. Precautions should also be followed when cleaning up areas that are contaminated with rodent droppings. Learn more.
There are multiple methods available for rodent control, each with their own advantages and disadvantages:
Snap Traps: traps are inexpensive, do not use poison, generally kill the rodent immediately, and are very effective for small infestations. However, they must be placed at the correct locations (e.g. along known rodent runways close to the nest, or where droppings are being noticed, with the trigger facing the wall). Keep in mind snap traps used for mice may not be effective on rats (and vice versa) due to the size difference between the animals.
Multiple traps are generally needed to control infestations, up to 1 every 10 feet apart from a suspected nest. No other food sources must be present so that the rodents will be enticed by the bait on the trap. For rat infestations, it is recommended to bait the trap but not set it until the bait is taken for a few days to overcome the rat’s inherent fear of new objects. Traps must be checked regularly and any caught rodents removed quickly, as surviving rodents (especially rats) may become trap shy if they see a caught animal. A rat that had a “near miss” with a snap trap is unlikely to be caught by the same trap.
Live Traps: Live traps do not use poison and are inexpensive; however, you will have to kill or relocate the trapped rodent yourself.
Glueboards: Glueboards are not recommended because they are not humane; trapped rodents usually suffer while still alive. If the glueboards are not regularly checked, death due to dehydration or starvation is prolonged while fighting and cannibalism amongst trapped animals can occur; rodents caught in glueboards need to be humanely euthanized as soon as possible. Partially stuck rats may chew off their limbs in order to escape, or may drag the entire trap away if only the fur is entangled. Glue traps become ineffective when the sticky surface becomes contaminated with excessive dust or dirt.
Rodenticides: Rodenticides are generally more cost effective at controlling large infestations, but have significant disadvantages. Only consider using rodenticide when trapping is not successful. Always read and follow all of the instructions on the product label prior to using rodenticide. Never use any pesticides that are not approved for use in Canada or use the products contrary to the instructions. There have been cases of human fatalities associated with improper use of pesticides. Unused or unwanted rodenticide is considered hazardous waste and cannot be disposed of as regular garbage.
Poisoned rodents do not die immediately after rodenticide consumption and may return to their nest before dying. The dead rodent, especially rats, will create a strong odor and retrieving the body may be difficult if the rodent dies in a relatively inaccessible area (e.g. inside walls, attics, or crawlspaces).
Certain rodenticides use blood-thinning agents to cause a delayed death; these anti-coagulant based rodenticides can poison animals that consume poisoned rodents. House pets, birds of prey and other urban wildlife can be fatally poisoned. There are non anti-coagulant rodenticides available (e.g. powdered corn cobs, bromethalin), but neither of these rodenticides can be used outdoors and bromethalin does not have an antidote in case of accidental ingestion by non target animals. If rodenticides are used, regularly check the outside of your property for dead rodents; if found, double bag the bodies prior to disposing in the garbage.
Ultrasonic Repellants: sound-based rodent repellents are generally ineffective; while the rodents may initially scatter, they will become accustomed to the noise and return.