Carpenter ants are named for their habit of working in wood. However, they do not build anything with the wood. The ants dig in the wood to make a nest. They excavate the wood but they do not eat it.
Carpenter ant workers normally gather insects and honeydew for the colony to eat. When food is scarce, the workers often enter homes in search of a food supply. Carpenter ants need a lot of moisture too, so a water source is often on their shopping list.
When the carpenter ant workers excavate wood for a nest, they create wood debris that looks like wood shavings. The workers push the debris out of the nest. Homeowners often find small piles of wood debris before they see any of the ants.
Carpenter ants also nest in the foam sheathing that homebuilders use during construction. Homeowners often find small pieces of foam on the ground beside the foundation.
In many cases, the main carpenter ant colony remains outdoors with the queen. Some of the workers make a satellite nest inside the home. The satellite nest is often in a void or hollow space. The ants will often move into the base of a cabinet, a wall void, or into the attic. Many homeowners report that they have heard the rustling sound of the ant workers moving around inside the walls.
Carpenter ants forage at night and on cloudy days. The workers move in a line along an established trail. They move between the satellite nests, the food supply, and the main nest outside.
When the workers move the entire colony inside the home, it is often into an area where there has been a moisture problem. Carpenter ants will readily excavate damp, decaying wood to make a nest. Homeowners often find carpenter ants in the wood in eaves, porches, bathroom walls, and in damp basements and crawl spaces.
In many states, carpenter ants must be reported on real estate inspection reports. Because the workers damage wood, it is probably smart to consider the sight of the wood debris or even a few of these ants to be signs of a possible problem.