The answer to 'why is my fire ant droppings' is that fire ants do not actually produce droppings. Fire ants are social insects that live in colonies and nest in the ground. The mounds or hills you see are the result of their nest-building activities, not droppings.
Fire ants are known for their aggressive behavior and painful stings. If you're seeing mounds or hills in your yard, it's likely an indication of a fire ant infestation. These pests can be difficult to control, so it's often best to call a professional pest control technician to properly identify and treat the problem.