Just tyed up a few of these for my trip to Chile. The wing uses Coq de Leon feathers. Fibers are cut off of the stem and placed in a Leon Hair Stacker which is a very, very small stacker for just such a job. The stacker is made of brass and is about 1/4" across and 2" long. It looks like a bullet casing. Using Coq for the wing gives the fly a much more delicate look.