CDC Mayfly (Step-by-Step Tying series)

When it comes to fly fishing, less is more. Be it a sparser pattern, smaller hook or a simpler pattern.

This week’s Step-by-Step tutorial is a prime example. While possibly frowned upon by purists who believe a Catskill style dry is the only true way to fish a mayfly hatch, this simple mayfly mimic will often out compete the more advanced and time consuming traditional dries.

Beyond it’s simplicity (requiring only four materials and half a dozen steps to tie), this pattern rides lower in the surface film than traditional dries while still remaining highly visible as the white CDC wing seems to glow through polarized lenses. Add in the fact that it can mimic everything from a Trico Dun to a Green Drake by merely swapping hook sizes and dubbing colors, and you’re left with a pattern that should be a mainstay in every trout anglers arsenal.

Tied in a wide range of sizes and dubbed to match the hatch, there’s always a place for this simple pattern in every angler’s box.

On to the tying:

Four flies in one; Trico, Baetis, PMD, Green Drake? Match the hatch by swapping out hooks and dubbing.

Materials List:

  • Hook: Dry Fly size 12 to 24
  • Thread: 8/0 or 12/0
  • Tail: Hareline Dubbin Mayfly Tails
  • Abdomen: Dubbing (match the hatch); Thread on smaller patterns
  • Thorax: Dubbing (match the hatch)
  • Wing: CDC Feathers (White)

Step 1:

Apply a few wraps of thread behind the eye of the hook. Trim off tag.

Step 2:

Tie in three CDC feathers approximately 1/3 hook length behind the eye. Tips of feathers should be aligned and extend just beyond the eye. Raise CDC tips vertically and apply a few wraps on each side of tuft to secure.

Step 3:

Trim excess CDC and wrap to thread to bend in hook.

Step 4 (Optional)

Apply a small amount of dubbing at bend in hook.

While not necessary, this dubbing ball will help spread the mayfly tails more easily.

Step 5:

Next, tie in mayfly tails using cross wraps to separate.

Step 6:

Finally, dub tapered body forward. Whip finish to complete.

Pro Tips:

Keeping your fly floating – Unlike traditional dry flies, floatants should not be used with CDC flies. These feathers are naturally buoyant due to their structure (microscopic hook like barbules provide increased surface area for trapping air bubbles) and somewhat water repellent due to oils exuded from a duck’s preen glands. Often a few false casts will sufficiently dry the fly between casts. Should false casts not suffice, commercially available desiccants should do the trick. Pop the fly in the desiccant container, shake and you’re back in business.

Proof of Concept:

Similar to my last Step-by-Step tutorial, proof of concept again flashes back to Eleven-mile Canyon in August of 2019. While the Trico spinner fall is certainly the headliner, there are far more hours to fish in the day and I was lucky enough to stumble upon an equally exciting hatch just before dusk: the Male Trico Emergence.

Returning to camp one evening, my cousin and I paused at a pristine stretch of river that had been crowded during the morning spinner fall. Now vacated of the day trippers in from Denver and Colorado Springs, we had the stretch all to ourselves. Fish were rising everywhere. As he moved upstream, I positioned myself just downstream of a large beaver lodge. With the light fading, and initially unsure of what the fish were feeding on, I tied on a #18 CDC Mayfly in PMD for visibility.

For the next hour, I could not keep the fish off of my line. While most were smaller (8″-15″) rainbows, I lost one rainbow (possibly a cuttbow) over 20″ at the net and landed this solitary, thick brown as well. While not as storied as the spinner fall, this evening emergence was perhaps the most memorable moment of the entire trip.

Eleven-mile Canyon Brown Trout

Tight lines everyone!


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