The collection of macronutrients (fats, carbohydrates, proteins) under natural conditions by the black carpenter ant, Camponotus pennsylvanicus (De Geer), was examined. Carbohydrate and crude protein were the primary macronutrients retrieved, with 2.3 times more carbohydrate than crude protein collected per trip. Only negligible amounts of crop lipid were detected. Collection patterns varied with macronutrient. Carbohydrate collection was consistently strong over all months, but varied between years and nests. In contrast, crude protein collection was consistent between years and nests, but exhibited peaks in June and September, when colonies typically contain mature larvae. Retrieved food was transported internally: <1% of returning foragers carried solid matter in the mandibles.