Two kinds of mice turn up most in and around Colorado homes. The house mouse is light brown to gray with a lighter belly and a naked tail, while the deer mouse has white feet and a gray to brown body that contrasts sharply with its white belly. Utah State University Extension notes that deer mice invade outbuildings in rural areas and are less common in town.
That difference affects safety, not just identification. The Weld County Department of Public Health and Environment reports that hantavirus in the county is mainly carried by deer mice. A homeowner cannot reliably tell which mice left droppings in a garage or attic, so we treat all rodent waste with care.
Season matters too. USU Extension notes that mice are most likely to invade structures in the fall, looking for food and shelter from the cold. In Northern Colorado, the weeks before the first hard freeze are when sealing does the most good.
For your home, that means we trace every opening before sealing, plan safe cleanup of droppings and nesting material and keep removal poison-free.