There are several signs that a person might notice that points to a significant carpenter ant infestation. First, the ants might be observed as they go about their work boring through wood. Simply seeing one ant might not indicate an infestation. Often, ants send out scouts to discover new sources of food and shelter. However, if there are several ants scurrying about, then it is a good idea to call on an exterminator to determine if there is a colony somewhere nearby. Second, carpenter ants often leave behind a sawdust-like substance called frass as they burrow into wood. This might be found in small piles near the nest, or it could be scattered about or caught on cobwebs. Finally, carpenter ants often form very tightly packed trails that lead to their nests. Because many of these signs can mimic other pests, a professional is the best person to call to positively identify a carpenter ant infestation.