House mice are a species of mice that live almost entirely inside human homes. It is not common for them to live in your yard. Wild mice, however, mice that are native to southern Ontario, will live in your yard. They will come to access your attic in the winter and to eat whatever food you leave out at other times of the year. These mice are not at all like house mice who came to America from Europe. They have been living with and feeding off human food for tens of thousands of years. Wild mice are native mice to North America. They do not know anything about humans other than our houses is warm in the winter. They have no interest in the food stored in the house and likely do not even know there is food in the house. Furthermore, they invade the attic for warmth in the cold months and leave daily to hunt for food outside. Bird feeders and dog food bowls will attract these wild mice. They will also be attracted to your property if you have open garbage. These mice are not a danger to the people living in the house but are a danger to the attic. An ongoing infestation every winter over several years can destroy your attic to the point that you may need to have a new roof installed.
Getting rid of these mice is similar to dealing with house mice. Make sure to remove any access to food on the outside of your home. For wild mice, this can be almost anything. Your garden or grounds may have access to nuts and berries wild mice like to eat. Unlike house mice who lost their ability to climb and jump, wild mice still have those skills and can reach food in the top branches of a tree. They can easily access a bird feeder and leftover food on the ground like pet food or food left from a party or barbecue will draw them in even faster. In the winter food is hard to find and humans have an excess. Make sure you seal your garbage and store it either in your garage or locked in a hard container. Do not give any animal or rodent a chance at accessing your garbage.
There are two main types of wild mice in North America. The deer mouse and the field mouse. The deer mouse is so named for its tendency to carry deer ticks. Deer ticks are highly dangerous and can drink blood even in their nymph stage which makes them very hard to find. The nymph stage of a deer tick looks like a tiny black dot. This tick can pass on Lyme disease to its host in very short times. Lyme disease is a bacterial illness spread by a type of bacteria called Borrelia burgdorferi. This bacteria will start affecting its host immediately but the symptoms are not permanent unless given twenty-four hours to incubate. The first sign, and the sign that should be sending you to the hospital in a massive rash around the bite mark. This rash will radiate in its form and will be yellow in the middle and bright red on the outside. This is the first sign and there is still time to get it dealt with. Other early symptoms are flu-like symptoms with a fever, tiredness and swollen lymph nodes. Muscle aches are also common symptoms. Lethargy is the clearest sign.
A rapid heart rate is also an early sign, if untreated the disease will cause palsies which are sudden and uncontrolled spasms of the body. The disease can then spread into your cerebrospinal fluid which may not be fatal but will have painful symptoms. If the disease is not treated in time then nerve damage will occur, this damage is permanent and will often take place in the brain causing arthritis, facial paralysis, heart issues and more. When getting home from walking in a park or forest make sure to check everyone for ticks.
The mice in the attic are not as likely to pass on ticks as they are in the wild, but they are still a danger and need to be dealt with. The best way to get rid of them is to take away their food source and replace it with domestic grade rodenticide poisons. You can then try finding the opening in the roof they are using to get into the attic and either sealing it off on your own or calling someone in to do it professionally.