The answer to 'why is my mouse droppings' is that the presence of mouse droppings indicates an active mouse infestation in your home. Mouse droppings are a common sign of a mouse problem, as mice will leave behind small, dark-colored pellets as they move around and forage for food.
Some common causes of mouse droppings include an entry point in your home that allows mice to get inside, available food sources like crumbs or pet food, and nesting materials like insulation or paper. Symptoms of a mouse problem can include hearing noises in the walls or attic, seeing mice or their droppings, and damage to food packaging or other household items.