Tying CDC Dry Flies Volume I

Mark’s Turkey Biot CDC Quill Gordon

It was thirty years ago when I wandered into my first fly shop. A gentleman by the name of Wally Vait was sharing space with another small sporting enterprise, the E&R Gunsmith, and he called his new business “On The Fly”. Wally helped me learn more about Maryland’s Big Gunpowder Falls, a growing new wild trout tailwater fishery in Baltimore County. It was there I found a few packets of Cul-de-canard or CDC feathers, and I have been tying CDC dry flies ever since. My very first truly original pattern used CDC to imitate the midges and microcaddis that trout ate readily in the upper reaches of the river, and it was an instant success. Pretty exciting stuff for a novice fly tier!

Even then the Gunpowder attracted a lot of fishing pressure. It was the home of a nice population of beautifully colored wild brown trout. It was a fairly small, clear water stream, and not often affected with high flows. Those wild browns and the few wild rainbows in that evolving fishery were difficult to catch, and I learned early on that CDC feathers offered movement and floatation. CDC flies caught fish better than standard flies on the river’s glassy pools.

When I moved to Pennsylvania to fish the limestone springs of the Cumberland Valley I encountered even more fishing pressure and difficult trout. Along the way I expanded my use of CDC in dry flies and used them to solve the puzzles of the legendary browns of the Letort and the wild Falling Spring Rainbows.

Fishing the Catskills for the past 27 years has exposed me to another world of challenging conditions. Our rivers are some of the most popular fisheries in the world. They are bug factories where trout thrive and grow to trophy size while feeding suspiciously and selectively on the multitude of natural insects. On all these rivers I have witnessed the effect of heavy fishing pressure, of trout exposed daily to great anglers and beginners, flawless presentations and extremely poor ones.

If you have ever watched closely as these wild trout feed on a good hatch of mayflies, you have seen them select only the naturals that were moving in their window. A good mayfly or caddis imitation that moves subtly in the microcurrents of the surface film is often the only way to catch these highly educated, selective fish.

Cul-de-canard feathers are easy to tie with and extremely effective for educated selective trout. They look natural, move to imitate life, and provide good floatation in the film. For the first video in this series I will show you how to tie a CDC comparadun with a turkey biot “quill” type body, one of my go to patterns for many years.


One note for biot bodies. If you want maximum durability for your flies I suggest coating the biot body with Hard as Hull acrylic polymer head cement as soon as the body has been wrapped. Tie a three turn whip finish, clip the thread, and set the hook aside until the cement is completely dry. Tie several flies to the same point then, when dry, add the wings and thoraxes one fly at a time. I usually don’t bother with this step, but it will make the biot body tougher.

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