The answer to 'why is my fire ant droppings' is that the 'droppings' you're seeing are likely not actually droppings, but rather the soil and debris that fire ants bring up to the surface when they build their distinctive mound-like nests. Fire ants are known for constructing these mounds, which can be unsightly and a nuisance in yards and gardens.
The mounds are created as the ants dig tunnels and bring up soil and other materials to the surface. This helps them maintain the temperature and humidity inside their nest. While the mounds may look like droppings, they are simply the byproduct of the ants' nest-building activities. Addressing a fire ant infestation requires proper identification and treatment to eliminate the colony.