EmergeradvancedRocky Mountain West
CDC Transitional Dun
Flybox sourcing profile
No TWG price or checkout is active. Use this page to validate the fly, then source it through the mapped tier or trusted fly shops.
Available Sizes#14 - #22
Color Variations
OlivePale YellowGrayRusty Brown
Pattern Ledger
Source CDC Transitional Dun
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Sourcing Ledger
Where to source this pattern
TWG checkout is closed. These are current sourcing leads, scored by mapped tier, region, species, fly type, and named-pattern evidence. Confirm availability directly with the tier or shop.
Regional shopStrong match
Taos Fly Shop
Matched on Rocky Mountain West, emerger flies, trout. New Mexico/Southwest trout shop lead for Rio Grande, San Juan, Pecos, and high desert water.
Rocky Mountain Westemerger fliestrout
Visit sourceSignature tierStrong match
Rocky Mountain Fly Design
Matched on Rocky Mountain West, emerger flies, trout. Colorado tier and shop lead for Rocky Mountain trout, bass, and predator patterns.
Rocky Mountain Westemerger fliestrout
Visit sourceSignature tierStrong match
Stillwater Fly Fishing Store
Matched on Rocky Mountain West, emerger flies, trout. Specialist stillwater source for balanced leeches, chironomids, and lake-trout logic.
Rocky Mountain Westemerger fliestrout
Visit sourceBroad sourceStrong match
Fly Fish Food
Matched on emerger flies, trout, mayfly. Strong technical tying and trout catalog coverage, especially nymphs, dries, and stillwater flies.
emerger fliestroutmayfly
Visit sourceBroad sourceStrong match
Fulling Mill Flies
Matched on emerger flies, trout, nymph. Large pattern house with broad freshwater and saltwater fly categories.
emerger fliestroutnymph
Visit sourceThe 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.
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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
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