Simplifying CDC

For more than 15 years, I have been fascinated by the humble duck feathers known as CDC. And from the beginning, it has been obvious that I can accomplish some things with this material that nothing else can duplicate.

CDC (cul de canard) feathers come from the preen gland of ducks. In appearance, they resemble small marabou blood feathers with unconnected fibers that radiate from tapered center stems. Soft yet strong, CDC floats remarkably well; flies tied with CDC are light and delicate on the water, and the fibers seem to pulse with the slightest breeze or motion of current. The ability to float a fly with less material lends a more realistic profile than is possible with conventional materials. Despite its subtlety, even a small amount of CDC is amazingly easy to see on the water. Yet for all its positives, CDC has remained a puzzle for many American fly tiers.

With a head start of several decades over Americans, our friends from across the pond are more knowledge­ able and experienced with CDC. European masters have developed sophisticated techniques and even specialized tools for working with CDC that have been introduced in recent magazine articles. After reading Dutch CDC authority Leon Links' best-selling book, Tying Flies with CDC (Stackpole Books, 2003), it is apparent that Americans are mere babes in the wood when it comes to tying with these feathers.

Less seasoned or less adventurous tiers in the United States may be intimidated by foreign techniques and designs that bear little resemblance to traditional Ameri­ can flies. I hope this will gradually change as more tiers gain an understanding of and proficiency with CDC. But in the interim, tiers with a little experience can benefit from CDC by integrating it into some of the classic patterns.

New and Improved Feathers

Since the early 1990s when CDC first became available in the United States in good supply, most CDC has come from large American poultry operations where ducks are harvested at an immature age. Individual feathers from this source are characteristically small and often are not completely developed.

In the beginning, my own CDC ties were mostly limited to sparsely treated patterns in relatively small sizes. This was partly by intent, because I most often fish small, sparsely tied flies, but it was also due to necessity–it was difficult to obtain feathers large enough for big flies.

In general, CDC from wild ducks is superior to the domesticated variety. The downside to wild CDC is an inconsistent and often inadequate supply dependent upon current huntable populations and, of course, the aim of the hunters in any given year. Although CDC from adult wild birds is typically larger and more fully fibered, it is mostly limited to two or three shades of gray. Pen­ raised ducks yield white CDC that is easily dyed. The best suppliers replace natural oils lost in processing to pre­ serve the full performance of their products.

Europeans have access to CDC feathers that are significantly larger and have much longer fibers than those available in the United States. Although far from vast or absolutely secure, the supply of European CDC has been adequate to reach a growing portion of the U.S. market. Although the performance is essentially the same, European CDC is clearly more versatile and therefore potentially more attractive to American tiers.

For me, the new CDC has prompted a rediscovery of what I call traditional fly-tying design. Using familiar patterns that have existed for 20 years or more as a basis, it is possible to demonstrate how CDC can easily accommodate conventional American concepts and techniques. The appearance of Dr. Tom Whiting and his extraordinary dry-fly hackle closely parallels the arrival of CDC in this country. Minus the quality and availability of Whiting Farms' hackle, much of what follows would not be worth mentioning.

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Tying with CDC

Plucked or trimmed from the stem, CDC fibers can be used as legs, tails, or antennae on emerging or floating patterns. The appropriate volume of fibers used is deter­ mined by the style of the fly or its flotation requirement, and they can be trimmed to the desired length. The same procedure can be used to install wings on midges or other small patterns where flotation or definition does not dictate a large volume of material.

Another method is to snip a small section from the feather in which the combined total of fibers on each side of the stem is equal to the amount needed for the purpose. Many tiers will find this technique to be the easiest.

Those who are fond of tying with hollow hair such as deer or elk can gain a similar effect by treating CDC the same way. The advantages of CDC are its superior flotation, no need to clean soft under­ fur from the hair, and no need to even the tips. The same applies to domestic calf tail and body hair, other popular components of hairwing flies.

For wings, I typically arrange two CDC feathers so the natural curvature of the stems causes them to flare slightly away from each other. Even the tips between your thumb and finger, and use only the portion of both feathers that provides the necessary volume of fibers. This means more for larger flies and progressively less as the size goes down. This makes a full and pronounced wing that does not bulk up on the hook shank. Absent in CDC wings is the rigidity of hair that causes the fly to spin and twist the leader and also the tendency to give early warning tl1at the fly is a fake when touched by an accepting fish. A natural insect is not usually stiff and unyielding.

Royal Wulff

Hairwing dry flies like the Wulff series require an upright and divided wing. When substituting CDC, mount the feathers with the tips facing forward over the eye of the hook. Elevate the wing with tight turns against the forward base, and divide the fibers equally with figure­eight turns of tying thread. As with hair, bundle the CDC fibers into individual wings with two or three turns around the base of each one.

Caddis and Stoneflies

CDC feathers make excellent low-profile wings such as those required for caddis or stoneflies. Again, the feathers are paired but with the curvature of each stem facing in the same direction. Stacked this way, mount the CDC over the body with the tips pointing to the rear and the curvature facing down. Use light pressure with two turns of thread to allow adjustment in the wing length by sliding the paired CDC in the appropriate direction. Tighten the initial thread wraps, and acid two or three more to secure the wings in place.

A slightly elevated profile can be obtained by using the same technique as for upright and divided wings. Face the tips of the paired CDC to the rear rather than forward, and tie them in firmly at the front of the body. Thus applied, the CDC feathers are set on their edges rather than lying flat over the back of the fly. This style of winging works especially well for fluttering caddis and flying ant patterns. I routinely tie adult salmonfly patterns up to size four by reserving the largest CDC for this purpose. Drys in sizes 8 through 12 are no problem if you are working with the best CDC.

CDC Adams and Traditional Drys

Hackle-tip wings like those used on the legendary Adams are fundamental to American fly tying. They are usually the first feathers we try when learning to tie wings on a dry fly, and many tiers see no reason to progress beyond this comfortable point.

Paired CDC feathers adapt readily to this easily mastered technique, and the tradeoff is more than justified. Retain the delicate sparseness of the classic American dry fly by using smaller CDC feathers or by working closer to the tips if the CDC is oversized for the purpose. Either way, it is a simple matter to pair the CDC feathers and mount them on the hook exactly as though they were hackle tips. The result is more visible, buoyant, and durable wings than could ever be accomplished with hackle tips.

CDC Terrestrials: Beetle and Ant

Deer- or elk-hair beetles are remarkably attractive to trout, but they easily become waterlogged and difficult to float. One of my favorite flies uses almost the same tying techniques as a hair beetle, but I use CDC instead.

The shell back is two or more prime CDC feathers tied in by the tips at the rear of the hook shank with the butt ends secured at the head over a portly body of peacock herl. Use two weak turns of thread to hold the CDC in place, and then push it gently back toward the bend to cause a slight "humping" effect. Lock the CDC in place with tight turns of thread, and whip-finish the head beneath the tie­down area. Trim the CDC butts behind the eye just as in the hair version of the fly. Some of my most effective emerging patterns use this same technique of creating a CDC bubble over the top of the fly, which increases its flotation.

Ant. In assorted colors, this pattern is as important to my summer fishing as any I carry. Winged ants are especially prevalent on hot summer days on most lakes and streams in the Yellowstone region.

The buoyancy of a CDC Flying Ant expands the type of water where this important fly can be used to include quick, bumpy currents such as the Madison. Not only does a CDC Ant float high, the CDC wing also makes the fly easy to see.

Mount the tips of two CDC feathers on edge just forward of the abdomen. The stems should curve away from each other and extend slightly beyond the hook bend.

Another application for a CDC-backed fly is to use the material as a substitute for hair when tying the popular Humpy. A CDC Humpy is easily equal to the original model, and it takes about 25 percent less time to tie.

CDC Thorax Dry

Dry flies with a single-post wing are common occupants of American fly boxes. One of my all-time favorites is a thorax style that may be as close to a perfect mayfly dun as anything I have ever fished. The wing is formed with paired CDC feathers mounted just slightly forward of the center point on the hook shank. The CDC is bundled into a single column with two or three turns of thread at the base of the feathers. I use Coq de Leon for the flared tail and wrap a stripped goose biot to form a trim, segmented abdomen. A sparse collar of hackle over a dubbed thorax is clipped on the bottom to form a wide V. The CDC Biot Thorax balances beautifully on the water and even at a short distance is easily mistaken for a natural.

Parachute

Parachutes are perhaps as popular as any dry fly in An1erica due to their effectiveness and easy visibility. Like the thorax style, a parachute dry fly can be improved with a light and durable CDC wing.

The winging technique is the same as the one used for the thorax fly, but the CDC post is tied in closer to the eye of the hook. Unlike the thorax, however, the natural tips of the CDC are not incorporated into the finished wing. Instead, mount the paired CDC farther down the feathers where the center stems are somewhat larger in diameter. This results in a wing that is considerably longer than necessary, but it has a significant purpose. Prepare a base for the hackle by bundling the CDC feathers with turns of thread that extend slightly up the base of the wing. Complete the fly by wrapping the hackle around the wing base and securing at the head. With scissors, trim the excess length of CDC to the height you desire. Tied in this way, the CDC fibers will fan into a broad and attractive wing profile. Using the thicker portion of the center stems creates a sturdy base for the hackle, and the result is a much more durable fly.

CDC Dubbing

I once placed a size 10 hook covered only with CDC dubbing in a bowl of water. Three days later the hook was still floating. CDC dubbing looks similar to Hare's­ear dubbing, although it is much softer. The exposed fiber ends function much like palmered hackle on caddis and stonefly patterns.

CDC dubbing can be used with common dubbing techniques, and its buggy appearance yields a unique imprint on the water. I find it to be especially suitable for a number of emerger and caddis patterns, as well as for thoraxes on duns and spinners.

CDC Drake

The reversed-feather method of tying a fly body that extends away from the hook has been popularized over the years by a number of American tiers. Among other applications, it works well for large drake imitations because it eliminates the need for an excessively long and heavy hook.

This easy technique is normally performed using a broad, long-fibered body feather such as mallard flank. With the fibers of both sides of the feather stroked back along the center stem and held in place at the base, secure the body at about the center point of a short-shank hook using tight turns of thread. Add wings, hackle, and a clubbed thorax (optional) to complete the fly. Tails are formed by snipping all but two fibers from the tip of the feather that is not involved in the body. A stronger and higher floating body is obtained when the original body feather is replaced with CDC. Further advantage is gained if CDC is used for the wings.

For many who have struggled to understand CDC and its potential, it makes sense to look closer to home for the solution. To a large extent, I believe this will help dispel the notion that flies using CDC must look and therefore be tied in a completely different manner than what we are accustomed to. Generally speaking, CDC lends itself comfortably to familiar and fundamental American concepts and techniques. This means that anyone in this country possessing the basic rudiments of fly tying should easily be equipped to capitalize upon the capabilities of this wonderful feather.

This is not to imply that the unique contributions of differing fly-tying cultures should be criticized or ignored, and that certainly is not my point. The innovative European designs and techniques are brilliant, and even the most skilled American tiers can benefit from their genius. But in pursuing all things new and perceived to be difficult, there must be a logical starting point. Tying with CDC can be simplified by beginning with what is familiar and working forward from there. From experience, I can confidently state that CDC has the ability to expand the effectiveness of nearly any well-designed and constructed dry fly. And learning to use it properly is well worth the effort.

Treating and Caring for CDC Flies

No fly, regardless of its composition, will consistently fool fish if presented incorrectly. Even CDC will not cancel a poorly executed cast and flies must be treated properly to perform their best.

CDC flies are not unsinkable, especially with sustained use. As with any floating pattern, a CDC fly needs periodic maintenance while in use. This is especially true if the fly is fooling a lot of fish. Negative residue can be quickly rinsed away in the water and flotation restored by pressing the fly between the folds of a buckskin or amadau drying patch.

High-quality CDC itself requires little or no supplementation to its natural flotation capability. However, the other components of a CDC fly, such as dubbing and cock hackle, often need a gentle fly dressing. A light oil floatant made with real preen oil takes the risk out of using a commercial fly dressing on a CDC fly. Even a CDC-based floatant should be applied sparingly.

CDC Fly Recipes

CDC Royal Wulff

• HOOK: #12 Tiemco 100BL.
• THREAD: Black 8/0 Uni-Thread.
• TAIL: Dark brown CDC fibers.
• BODY: Peacock herl and red floss.
• WINGS: Paired white CDC feathers.

CDC Humpy

• HOOK: #12 Tiemco 100BL.
• THREAD: Yellow 8/0 Uni-Thread.
• TAIL: Light brown CDC fibers.
• BODY: Two light brown CDC feathers over yellow Rene Harrop Professional Dry Fly Dubbing.
• WINGS: Paired light brown CDC feathers.
• HACKLE: Whiting grizzly and brown, mixed.

CDC Classic Dry (PMD)

• HOOK: #14 Tiemco 100BL.
• THREAD: Yellow 8/0 Uni-Thread.
• TAIL: Whiting Coq de Leon.
• ABDOMEN: PMD Trouthunter goose biot.
• THORAX: PMD Rene Harrop Professional Dry Fly Dubbing.
• WINGS: Paired light dun CDC feathers.
• HACKLE: Whiting grizzly dyed pale yellow.

CDC Extended Body Drake (Gray Drake)

• HOOK: #12 Tiemco 206BL.
• THREAD: Gray 8/0 Uni-Thread.
• TAIL: Fibers from CDC body.
• ABDOMEN: Medium dun CDC feather tied reverse style.
• THORAX: Muskrat Gray Rene Harrop Professional Dry Fly Dubbing.
• WINGS: Paired medium dun CDC feathers.
• HACKLE: Whiting grizzly dyed medium dun.

CDC Palmered Caddis

• HOOK: #14 Tiemco l00BL.
• THREAD: Tan 8/0 Uni-Thread.
• BODY: Hendrickson Rene Harrop Professional Dry Fly Dubbing.
• HACKLE: Whiting dark ginger grizzly.
• WINGS: Paired light brown CDC.
• ANTENNAE: Two wood duck fibers over wings.

CDC Biot Mayfly Emerger (Brown Drake)

• HOOK: #10 Tiemco 200RBL.
• THREAD: Tan 8/0 Uni-Thread.
• TAIL: Wood duck fibers.
• ABDOMEN: Tannish yellow turkey biot.
• THORAX: Tannish yellow Rene Harrop Professional Dry Fly Dubbing.
• LEGS: Brown Hungarian partridge.
• WINGS: Paired dark brown CDC feathers.

CDC Salmonfly Adult

• HOOK: #6 Tiemco 200RBL.
• THREAD: Orange 8/0 Uni-Thread.
• TAIL: Moose hair.
• ABDOMEN: Whiting brown hackle palmered over Rene Harrop Professional Dry Fly Dubbing.
• WING: Paired dark brown CDC feathers mounted flat over abdomen.
• THORAX: Trico Rene Harrop Professional Dry Fly Dubbing.
• HACKLE: Whiting brown.
• ANTENNAE: Two moose hairs.

CDC Thorax (Mahogany)

• HOOK: #14 Tiemco 100BL.
• THREAD: Rust 8/0 Uni-Thread.
• TAIL: Whiting Coq de Leon.
• ABDOMEN: Mahogany Trouthunter goose biot.
• THORAX: Mahogany Rene Harrop Professional Dry Fly Dubbing.
• WING: Paired dark dun CDC feathers.
• HACKLE: Whiting grizzly dyed brown.

CDC Fledgling Caddis

• HOOK: #14 Tiemco 206BL.
• THREAD: Tan 8/0 Uni-Thread.
• BODY: Dark brown Trouthunter CDC dubbing.
• WINGS: Paired dark brown CDC feathers.
• LEGS: Brown Hungarian partridge.
• ANTENNAE: Two wood duck fibers over wings.

CDC Parachute (Adams)

• HOOK: #12 Tiemco 100BL.
• THREAD: Gray 8/0 Uni-Thread.
• TAIL: Whiting Coq de Leon.
• ABDOMEN: Gray Trouthunter goose biot.
• THORAX: Muskrat Gray Rene Harrop Professional Dry Fly Dubbing.
• WING: Paired white CDC feathers trimmed to length.
• HACKLE: Whiting Cree or brown and grizzly, mixed.

CDC Beetle

• HOOK: #12 Tiemco 206BL.
• THREAD: Black 8/0 Uni-Thread.
• BODY: Peacock herl.
• LEGS: Black CDC fibers trimmed to length.
• SHELL BACK: Paired black CDC feathers pulled over body.

CDC Flying Ant (Honey)

• HOOK: #14 Tiemco 206BL.
• THREAD: Tan 8/0 Uni-Thread.
• ABDOMEN: Light honey Rene Harrop Professional Dry Fly Dubbing.
• STABILIZERS: Two moose hairs.
• WINGS: Paired brown CDC feathers.
• HACKLE: Whiting furnace.
• THORAX: Brown Rene Harrop Professional Dry Fly Dubbing.

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[Rene Harrop Professional Dry Fly Dubbing, distributed by Trouthunter (www.trouthunt.com), is a blend of natural and synthetic fibers dyed to match important insect colors. The dubbing is coordinated to match Trouthunter goose and turkey biots. You can buy top quality CDC from Trouthunter or Marc Petitjean (www.petitjean.com). THE EDITOR.]

Rene Harrop owns and operates Trouthunter outfitters in Island Park, Idaho. He is the author of Trout Hunter (Pruett Publishing Co., 2004)