 But they were really standing there like the first piece of land that they could see. They barely could fly. So when I stepped close, the butterflies usually fly and leave. These ones didn't fly. They just jumped a little bit trying to escape. But I felt they had no energy to do much more than that. You surmised that these butterflies had made a transatlantic journey with no pit stops. It took you some detective work to test this theory out, though. How did you do it?