Workers from multiple queen colonies are not territorial,they freely move from one mound to another, which has resulted in a dramatic increase in the number of mounds per acre. In areas with multiple queen colonies, there may be 200 or more mounds and 40 million ants per acre. The red imported fire ant builds mounds in almost any type of soil, but prefers open, sunny areas such as pastures, parks, lawns, meadows and cultivated fields. Mounds can reach 18 inches in height, depending on the type of soil. Many times mounds are located in rotting logs and around stumps and trees.
Colonies also can occur in or under buildings.
When their mounds are disturbed, their workers will come out of the ground and sting the intruder very aggressively. The red imported ant can have huge colonies with 300-500,000 workers foraging at distances of 100 yards. Their usual activity is from the spring time through the fall months. During the spring and summer months, the active mounds will send out winged swarmer ants, whose sole job is start new colonies. The southern fire ant will usually nest in loose soil, but at times they can be found in woodwork or masonry.