Skip to content
The Woolly Gentleman logo

The Woolly Gentleman

Every Fly Has a River · Every River Has a Tier

ShopSubscribeOur TiersJournalFind Your FliesThe CraftThe Story
Home/Shop/CDC Transitional Dun
CDC Transitional DunEmergeradvanced

Rocky Mountain West

CDC Transitional Dun

$3.95

Available Sizes#14 - #22
Color Variations
OlivePale YellowGrayRusty Brown

The CDC Transitional Dun occupies the narrow space between emerger and adult -- neither fully hatched nor still emerging, but caught in the vulnerable moment of transformation that trout find most appealing. The CDC wings provide both floatation and a realistic wing silhouette, while the trailing shuck anchors the rear of the fly in the film. It is a fly designed for the angler who has watched too many trout eat something they could not identify, right at the surface, and decided to tie a pattern that exists in both worlds at once. The trout approve. They always approve of vulnerability.

Quick Facts

TypeEmerger
Difficultyadvanced
SeasonsSpring, Summer, Fall
Target SpeciesRainbow Trout, Brown Trout, Cutthroat Trout
Sizes#14 - #22
Best LocationsHenry's Fork, ID; Missouri River, MT; South Platte River, CO

Where to Fish It

Henry's Fork

ID · Spring Creek

Missouri River

MT · Tailwater

South Platte River

CO · Tailwater

Map unavailable. Locations for CDC Transitional Dun: Henry's Fork, ID; Missouri River, MT; South Platte River, CO

Related Reading

seasonal playbook

The Spring Playbook: First Hatches to Full Send

Spring is the most dynamic season in fly fishing — water temperatures swing daily, hatches emerge in waves, and fish that have been dormant for months begin feeding with increasing urgency. This is your region-by-region playbook for fishing the awakening.

hatch guide

The Complete Guide to Mayfly Hatches

Mayflies are the foundation of trout-stream entomology. This guide covers every major hatch — BWOs, PMDs, Green Drakes, Sulphurs, Tricos, and Hendricksons — with the biology, timing, and fly selections you need to fish them effectively across the country.

hatch guide

Emerger Patterns: Fishing the In-Between

Trout eat more insects during emergence than at any other stage. Emerger patterns — flies that imitate the critical moment when a nymph transforms into an adult in the surface film — are the most consistently effective dry flies in fly fishing. Here is the science and the technique behind fishing the in-between.

You Might Also Like

CDC EmergerEmergerintermediate

CDC Emerger

$3.50

Rocky Mountain West

#14 - #22

Cul-de-canard feather emerger. Natural oils in CDC float the fly in the film. Imitates a mayfly struggling to hatch.

OliveTanGrayRusty Brown

Rainbow Trout · Brown Trout · Cutthroat Trout

SprSumFallWin
View Details →
Sparkle PupaEmergerintermediate

Sparkle Pupa

$3.50

Rocky Mountain West

#12 - #18

Gary LaFontaine's caddis emerger. Antron sparkle yarn creates a bubble effect mimicking the gas sheath of an emerging caddis pupa.

TanOliveBrownDeep Sparkle Amber

Rainbow Trout · Brown Trout · Cutthroat Trout

SprSumFallWin
View Details →
Barr's Emerger (BWO)Emergerintermediate

Barr's Emerger (BWO)

$3.95

Rocky Mountain West

#16 - #22

John Barr's Blue Wing Olive emerger. Tungsten bead, trailing shuck, CDC wing. Designed for the transition zone between nymph and dun.

BWO OlivePMD Pale YellowGray

Rainbow Trout · Brown Trout · Cutthroat Trout

SprSumFallWin
View Details →
RS2Emergerintermediate

RS2

$2.95

Rocky Mountain West

#18 - #24

Rim Chung's minimalist emerger. CDC or beaver fur wing, thread body. Imitates emerging Baetis and midges in the surface film.

OliveGrayBlack

Rainbow Trout · Brown Trout

SprSumFallWin
View Details →
Parachute AdamsDry Flybeginner

Parachute Adams

$2.95

Rocky Mountain West

#12 - #22

Tied by Andy Carlson

The universal dry fly. Grizzly hackle, white post, dubbed body. If you cannot identify the hatch, tie on an Adams.

Standard GrayFemale (yellow egg sac)

Rainbow Trout · Brown Trout · Cutthroat Trout · Brook Trout · Mountain Whitefish

SprSumFallWin
View Details →
Elk Hair CaddisDry Flybeginner

Elk Hair Caddis

$2.95

Rocky Mountain West

#12 - #18

Tied by Chris Krueger

Al Troth's iconic caddis imitation. Elk hair wing, palmered hackle. Floats like a cork in fast water.

TanOliveBlack

Rainbow Trout · Brown Trout · Cutthroat Trout · Brook Trout

SprSumFallWin
View Details →

The Woolly Gentleman

Every Fly Has a River · Every River Has a Tier

America's curated artisan fly marketplace. Every pattern hand-tied by the people who fish these waters.

Join the mailing list. We will tell you what is hatching.

The Shop

  • Browse All Flies
  • Our Tiers
  • Find Your Flies
  • The Collection
  • Monthly Delivery
  • The Journal

Fishing Regions

  • Gulf Coast & Emerald Coast
  • Florida Keys
  • Northeast & Mid-Atlantic
  • Rocky Mountain West
  • Pacific Northwest
  • All 10 Regions

The Gentleman

  • Our Story
  • Nationwide
  • hello@thewoolygentleman.com

© 2026 The Woolly Gentleman. All rights reserved.

Privacy Policy|Terms & Conditions

Curated with conviction. Tied with pride.