What might indicate a significant infestation of ants around a structure?

The presence of foraging ants is a strong indicator of a significant infestation around a structure. Foraging ants are actively searching for food resources, which often leads them away from their nest and into areas surrounding buildings. When numerous ants are seen foraging, especially in organized trails, it suggests that there is a larger colony nearby. These foraging behaviors often point to a reliable food source in or near the structure, further emphasizing the likelihood of an infestation.

Other indicators, such as the absence of other pest species or the visibility of just a couple of ants, don't necessarily reflect the level of ant activity or the size of the colony. While unusual ground colors might suggest the presence of ants, it’s not a definitive sign of an infestation as there can be various reasons for such changes in color unrelated to pest issues. Therefore, observing active foraging behavior is the most direct and reliable sign of a significant ant presence.