Euchloe olympia was studied in a sand prairie in central Illinois each year for a period of five years to monitor behavior. Adults were followed by groups of observers; groups tracked the type of flowers utilized for nectar, the flight time between visits to plants or the substrate, the distance flown between each plant or substrate, and any additional behaviors (such as oviposition and courtships). We made over 1300 observations of 53 butterflies. Individuals were found to differ significantly in various aspects of their behavior; including nectar source, average time nectaring and flight activity. The main larval food plant was found to be Lepidium virginicum, while the main adult nectar source was found to be Nuttallanthus canadensis. Individuals consistently showed considerable constancy in the flowers they visited.