A few years ago, I started using Ostrich Herl for the abdomen of The Orb Emerger (Callibaetis pattern). I also used Ostrich Herl for the tail and as emerging wings. I like the results. I have to believe there is a subtle yet recognizable movement to suggest life in motion. So far, I have only used this pattern on lakes over Chironomid and Callibaetis hatches with some success.