The CDC Comparadun BWO is a perfect fly to use during a spinner fall of Blue Wing Olive or any other olive mayflies. The Compardun pattern is used to imitate adult and spinner stages of mayflies. Spinner stages are when the mayflies end their life and fall back onto the water with their wings often laid out. The profile of this fly imitates that well or even adult mayflies who are on their sides or just newly hatched.
Sitting lower in the water than both the Parachute BWO and the Thorax BWO, the BWO CDC Comparadun makes it appear trapped in the surface film, and is among the most visible adult (dry) Blue Winged Olive Mayfly patterns to the feeding trout.