Nervous feeding

Despite there being very many smaller flies on the surface our fish only has eyes for the BWO. Notice he returns to his original station but is slightly concerned about the camera, the tripod and the man on the bank. Those snapping rises indicate nervousness. He would be a difficult fish to catch. The more I think about it, the more it becomes clear that the knack to successful dry fly fishing is keeping yourself concealed from the fish and not underestimating its ability to know you are there.