Each spring, I notice a small pile of fine debris on the outside wall of my garage, which is actually inside (don't ask). There is a small brownish trail that leads up about 8" into the morter. I can faintly detect a tiny hole but not sure. I usually spray it with all of the bug killers on hand.
Yet, the trails continue every year.
Anyone experience this or have a clue what it might be? Should I worry that they are burrowing through the brick and one day the house will come tumbling down?