Rats & Mice Problems
Although British Columbia is home to more than twenty types of rodents, only three cause common domestic or farmyard problems. The three species most likely to invade your home or farm outbuildings are the house mouse, the Norway rat, and the black rat. All three originated in Europe before the 20th century.
Rats and mice can pose a serious threat to property and health. They cause building damage by chewing on insulation, sidings, and wallboard. They will eat a wide variety of stored food. These rodents will often contaminate food that they don't eat, which could lead to food poisoning, as well as leaving a mess in your cupboards.
All three types of rodents can also transmit diseases, which are carried on their feet and spread through their urine, droppings or bite. The ticks and fleas carried by rodents can also spread diseases. See BC HealthFile #01 Tick Bites and Disease for more information.
Rats and mice are easier to detect and leave plenty of evidence. They will chew cereal boxes or dried foods in plastic bags, leaving quite a mess behind. Chewing marks on woodwork and plumbing pipes are other signs of a rodent infestation. Dark brown rodent droppings are commonly found at eating sites and other areas. Rats and mice often burrow in the ground under sheds, garages, and foundations, and in between walls.
It is possible to hear them moving around or even chewing when your house is quiet.
Rats and mice breed rapidly, so it is important not to let them get established on your property. Even if you don't spot an actual rodent, the size of the droppings will tell you whether you are dealing with mice or rats (mouse droppings are approximately 1/4 inch long, and rat droppings measure up to 3/4 inch).
The best way to get rid of rats or mice is by using traps. Buy several of the appropriate snap traps from a hardware store and bait them with dried fruit or 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 when disposing of the trapped animal. They should be wrapped in plastic and placed in the garbage.
Rats will only stay on your property if food, water and a place to live are available.
There are a number of steps you can take to make your property less attractive to rodents.
1. Eliminate food and water sources:
- Keep all garbage in metal containers with tight fitting lids.
- Do not leave pet food outside overnight. Remove it right after feeding.
- Bird feeders should be equipped with trays to catch spillage; spilled seeds should be cleaned up often.
- Remove fallen fruit and nuts.
- Clean out waste and food from pet pens and enclosures.
- Repair any plumbing leaks to remove water supply.
- Cover pools and whirlpools when not in use.
- 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.
2. Eliminate hiding and living places:
- Remove all unused piles of lumber, old sheds, or buildings.
- Do not store old cars or furniture outside.
- Store lumber and firewood on stands twelve to eighteen inches off the ground.
- Do not plant shrubs or flowers right next to buildings. Keep a space clear between plants and buildings and allow six to eight inches under plants. Keep grass and ditch areas trimmed.
3. Protect buildings
- Cover crawl spaces, fresh air and attic vents with 1/4 inch metal screening or steel mesh.
- Repair cracks in cement footings and foundations.
- Build sheds on concrete slabs.
- Install 1/4-inch hardware cloth inside your compost.
It is not a good idea to use poison or baits to control rodents unless all other control measures have failed. Poisoned animals crawl away to die; their decomposing bodies not only smell bad, but are often hard to retrieve and can be breeding grounds for disease. Poisons can also accidentally harm pets, wild animals, or even children. Ultrasound repellers, although initially effective, are expensive and don't seem to have long-term success at eliminating unwanted rodent populations.
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 rats get used to feeding in this area.
- Several types of rat poisons can be found in local hardware stores and garden shops. 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 becomes rancid.
- Remove dead rats and all baits once pest control has been completed.