CDC Dun

Materials

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Hook TMC 103bl #19-21
Thread Uni Thread 8/0 , Olive Dun
Body Super Fine Dry Fly Dubbin, BWO
Tail Light Dun Tailing Fibers
Wing Med Dun CDC
Thorax Super Fine Dry Fly Dubbin, BWO
Actual Blue Wing Olive
Actual Blue Wing Olive

CDC Dun

The CDC Dun utilizes Cul-de-canard (CDC) feathers for the wing on this mayfly emerger pattern. The use of the feather has their roots going back to the 1920’s with the Moustique patterns used in the Jura Mountains of Switzerland. The feather is found near the preen glands of ducks. The preen gland produces an oil that coats the duck’s feathers. This coating of oil makes the duck’s feathers very water resistant and thus buoyant. The oil itself eventually spreads over the entire duck, but the CDC feathers are the most saturated because they’re nearest to the gland. It was first marketed in the United States in 1990 by Dennis Black of Umpqua Feather Merchants.

Shane Stalcup

Shane StalcupThe late Shane Stalcup was one of the early tiers to utilize this material in the United States. He adapted the feather as a replacement for the Deer Hair wing on a Comparadun pattern in the late 1980’s. The feather can also be tied in a comparadun style without a hackle due to the high floatation character. Certainly, this is a progression of the No-Hackle pattern that was introduced by Swisher and Richards in the 1970’s.

Parachute Dun style

In addition, CDC can be used as a wing post with a parachute hackle surrounding the post. Rene Harrop wrote about this feather in the July issue 1991 of Fly Fisherman magazine and showed his version of a CDC Parachute Dun. The use of this feather as a hackle will provide a somewhat higher profile and will withstand faster currents. Further, Marc Petitjean also popularized many techniques for utilizing the feather creating dun patterns with split wings.

Dun style

The CDC Dun can be tied in a number of sizes and colors to mimic a newly emerged mayfly. The style is particularly useful on small mayfly patterns such as PMDs or BWOs since the CDC wing provides very good floatation for a small hook size. The pattern remains simple with its tail of microfibetts or tailing fibers. The body can be tied with dubbing or quill, producing a slender, thin body. The wing is located above the thorax position and can be tied using a number of techniques. The simplest technique is to tie two plumes with the tips facing over the eye of the hook, pulling the plumes until the tips equal the length of the shank. Then, trim the back half of the feather with a taper. Another technique is to trim the fibers off two plumes and anchor these fibers to the thorax region, pulling the fibers for desired length. The two plume tips are secured in front of these fibers and secured upright for wings.

 

Variations

CDC Dun Callibaetis
CDC Dun Callibaetis

CDC Callibaetis Dun

Hook TMC 103bl, #13-15
Thread Uni-thread Gray 8/0
Body Superfine Callibaetis
Thorax Superfine Callibaetis
Tail Med Dun Tailing Fiber
Wing Light Dun CDC
CDC Biot Parachute Dun
CDC Biot Parachute Dun

CDC Biot Parachute Dun

Hook TMC 100, #14- 18
Thread Uni-thread Gray 8/0
Body Gray Goose Biot
Thorax Muskrat
Tail CDL Med Pardo Tailing Fiber
Wingpost White CDC
Hackle Grizzly Dun Rooster Cape