CDC Biot Comparadun
This terrific fly improves upon a great fly by the substitution of a goose biot for the abdomen, and CDC for the wing. There are many theories as to why this fly is such a favorite among fly fishers. My personal belief is that it’s slender, low-riding profile (coupled with the very natural segmented-look the biot gives) is an accurate representation of more than one stage of a mayfly’s life. In other words, if the trout will take this same fly as a floating nymph, emerger or dun, your chances of hooking a trout on it increase dramatically. I’ve trimmed the tail off and fished it as a caddis, trimmed the tail off a pale yellow one and fished it during a cranefly hatch, skittered it, pulled it under etc….etc…etc…This is truly one of my top-picks in the dry fly department. I have a fly box devoted entirely to this fly in various sizes and colors, including some spinner variations.
Tying The CDC Biot Comparadun Fly
Hook:Tiemco #101 (or standard dry fly hook)
Thread:8/0 rusty dun or tan
Tail:Dun Microfibbetts
Abdomen:Olive/dun goose biot
Wing:Type 1 CDC feathers, natural color
Thorax:Olive Superfine dubbing
Tie in thread, wind back and tie in 4 microfibbetts, tips aligned. Using your finger, push them up to help keep them in position while you separate them
Grab the far 2 microfibbetts and pull them up, and away. Make a thread wrap between the 2 bunches. Grab the 2 nearest you and make a thread wrap from underneath, up and through the 2 bunches. Make a wrap behind both bunches and a wrap in front to secure the lot. Trim the butts.
Strip a goose biot from the stem and tie in as shown, with "notch" at the base of the biot facing back. Using your hackle plies wind the biot forward, tie off and trim butts.
Select 3 or 4 Type 1 CDC feathers and stack them as shown, with tips aligned.
Stroke feathers to make it easier to tie in, measure wing to be approx. the length of the hook shank. Tie on, making sure the wing sits on top of the shank, and does not roll around it.
When wing is secure (about 3 firm wraps) trim the butts of the CDC feathers, trying to make sure they are cut so that the thorax will dub with a nice taper. (trim at an angle)
Begin dubbing the thorax behind the wing. Lift the wing and force it back as shown. The feathers are tied in flat, thats how they want to stay. Use some force. The dubbing alone can’t hold that wing in an upright position. Dub in front of the wing, tight against it with a few wraps. Using the thread, form a small thread head and tie off.
Using 2 hands, pull the sides of the wings down to create a "fan" shape as shown. If necessary, push back some more. You can make minor adjustments to the position of the wing once its bound in an upright position.
