Here in the Austin area we have nice large trees and with the trees come carpenter ants. They are part of the wood destroying organisms (WDOs) which inspectors are looking out for.
Unlike termites, carpenter ants do not eat wood, but rather excavate wood material for use as a nest. Like termites, carpenter ants are considered social insects and their presence, although not frequently seen, can be large in number ranging from 10 to 20,000 workers. This means identifying them is not easy and requires looking for evidence of their existence in areas they desire. For positive ID, they are typically 1/4″-5/8″ in size and can be black, red and black, brown or red in color and may have wings or be wingless. (See Fig 1 above)
They prefer moist wood (19% or higher) which is why we must monitor for any signs of wood rot from moisture. Also, a colony must have a continuing source of moisture to survive. Outdoors this may be dead wood, or inside an overly wet or poorly ventilated crawlspace or attic.
They leave behind telltale signs of their existence called frass, consisting of wood shavings, excrement and body parts as seen in the image below.
They usually will enter buildings through cracks around doors, windows, or where utility lines pass through walls, and will travel over tree branches onto a structure.
Another reason for the high activity is because they mate in the Spring and are most active at night.
Carpenter ants feed on a wide variety of foods, including other insects, such as aphids, scales, and mealybugs; as well as dog food, seeds, bread, and honey, to name a few. Workers have been know to travel up to 300 feet from the colony in search of food.
Call a professional when ridding your property of these pests. Attempting to exterminate with unproven remedies usually results in frustration. The professionals can use such methods as barriers, drilling wood members, pressure injection, or applying dust.