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Mice in Calgary can cause a good deal of gnawing damage to food, clothing, walls, boxes, books and electrical wiring. These items can also become contaminated with their droppings and urine, and often have to be thrown away. Mice are also known to transmit a bacterium that causes food poisoning.

Preventing mice

Mice can squeeze through cracks as small as a dime, so it’s crucial to weather-strip doors and windows in your house and patch any cracks in the foundation or exterior. You should also cover dryer vents, attic vents or soffits with fine mesh.

Make your home less appealing to mice by taking the following steps:

  • Remove cozy nesting sites in unused clutter around the house and garage
  • Cut tall grass and weeds back from the house
  • Make sure garbage is secured in containers with tightly fitting lids, raise woodpiles about 30cm and place them away from the house
  • Never place fatty or oily food waste, eggs or milk products in a backyard composter. Keeping your compost material as moist as a wrung out sponge will deter mice from building nests in a composter. You can also install a layer of heavy metal mesh between the soil and the bottom of the composter as an effective barrier to prevent mouse invasion
  • Cleanliness in the kitchen is essential; dry goods, including grain and dry pet foods, should be stored in metal or glass containers

Getting rid of mice

Metal snap traps and live traps are easy to use and are very effective in ridding your home of mice.

Follow these guidelines for both types:

  • Set the traps at right angles to the wall, with the baited end of the trap closest to the wall.
  • Set a large number of traps, such as five to ten traps per visible mouse hole.
  • Allow a warm-up period of three to four days (bait the traps but don’t set them) so that the rodents become comfortable taking the bait.
  • Try using baits of strong-smelling, sticky foods (like peanut butter or bacon grease) mixed with oats, raisins or gumdrops.
  • You can re-use the traps, but move them to different locations if the bait does not start to disappear regularly.
  • Reset the traps in two to three weeks to catch maturing young mice.

Glue traps, sticky boxes or tube traps may be an effective choice if snap traps fail, or for use in hard to reach places. They can be used with or without bait.

Live and glue traps might appear to be more humane, but if you intend to release the rodents, check the traps daily. Mice quickly die of stress and exposure if they are held without food and water.

Ultrasonic devices emit sound waves or vibrations that rodents dislike. The devices may drive mice out of certain areas and into areas where baits or traps have been set. This may help increase the effectiveness of control methods. Mice may adapt to the devices over time and return to areas within the device range.

Poisoned baits are a common method of mouse control. The bait must be used in areas out of the reach of children, pets or non-target animals. Never scatter poison bait over the ground or inside a building. Bait stations (e.g. those used by professional pest control operators) must be tamper resistant. Read and follow all label directions and precautions.

Rodenticides should only be used as a last resort. Physical control methods and alternatives to pesticides should always be your first choice. When using pesticides, it’s important to identify the pest correctly and follow all of the proper procedures for the product. Safe handling of pesticides is critical, and you should have a contact number for a poisoning centre on hand.

Always wear gloves to dispose of dead rodents and always wrap rodents in a plastic bag.

Types of mice

Mice are a destructive rodent and unfortunately, they’re common in Calgary. There are two different types of mice in the Calgary area:

  1. The house mouse is found in urban areas. It is a small slender rodent with grey or light brown fur, a pointed snout and large ears.
  2. The deer mouse may invade buildings near fields and woodlands at the onset of cold weather. It is brown or grey in colour, with white belly and feet. The underside of the tail is white, which is perhaps the easiest way to distinguish between a deer mouse and a house mouse.

Mice have a wide-ranging diet and will eat just about anything. They prefer cereal grains, seeds and foods high in fat, protein and sugar. Those that live in outbuildings can live on weeds, seeds and insects.

What to do about mouse droppings

Mice are carriers of disease. Some diseases like the hantavirus are spread by contact with the urine and droppings, and breathing dust raised during the cleanup of droppings can cause serious illnesses.

Practice safe cleanup procedures with these tips:

  • Never sweep or vacuum dry droppings
  • Dampen droppings and debris with a bleach and water solution before wiping up
  • Wear rubber gloves and a mask during cleanup
  • Wash your hands and exposed clothing thoroughly after cleanup

​​​Learn more about common pests in Calgary​