I do not have much to add regarding the CDC blue winged olive that I did not previously convey on my 03/11/2014 CDC BWO post. This tiny fly continues to be a must have for my fly box throughout the season.
On November 23 I visited the Arkansas River tailwater in Pueblo for the first time, and I was lucky to experience a fairly dense blue winged olive hatch during the afternoon despite a clear blue sky. My size 22 CDC BWO produced three fish during the early stages of the emergence; however, it was largely ignored during the peak activity. I was in a prime position next to a long pool where at least twenty fish fed aggressively on tiny blue dun mayflies, and yet aside from a few temporary hook ups, I failed to land any fish.
Near the tail end of the lesson in frustration I seined the water and inspected the specimens that appeared in my net. I estimated that the mayflies were a size 24, and this probably explained my lack of success. I vowed to tie some size 24 CDC BWO’s, and I fulfilled that pledge during the first couple weeks of December. I tied ten minuscule blue winged olives, and then because I was not satisfied with the look of my carryover size 22’s, I manufactured ten more.
Despite its small size this fly is fairly easy to tie as it only involves three materials. The most challenging step is sizing the clump of CDC that is used to form the upright wing. I discovered through experience that an optimal amount of feather is necessary. If I make the wing too sparse, it mats readily and does not present a viable wing imitation. In addition once it gets wet it is very difficult to fluff back to the desired thickness. If the clump is too thick, the fly does not present an accurate silhouette, and the fish ignore it. In order to counter these difficulties, I strip CDC fibers from a feather and roll them into a clump. I gauge the thickness for proper bulk by focusing on the area just above my pinch because this section does not contain air spaces and more accurately portrays how the wing will appear once tied to the hook shank.