Back

Thistledown CDC Olive Mayfly Dun

by @dekasso

Thistledown CDC Olive Mayfly Dun — a fly pattern by Dekasso
More by @dekasso

CDC Quill Dun · Dry fly

A white tuft riding a quiet glide

A slender CDC quill dun on a size 16 dry hook, olive body and white wing, for trout and grayling during olive mayfly hatches.

A slim mayfly dun with a white CDC wing standing tall over a banded olive quill body. Speckled Coq de Leon tails, an olive thread head and a bronze dry-fly hook finish it.

Pattern
CDC Quill Dun
Imitates
Olive mayfly duns, typically spring and autumn afternoons
Hook
size 16
Tippet
5Xrule of three
  • White CDC wing sits high and visible
  • Banded olive quill body
  • Speckled Coq de Leon tails
  • Size 16 dry-fly hook
  • Matches olive mayfly duns

On the water

A dry fly riding the surface of a trout river

A soft white plume rises from a body striped olive and brown, like a reed in low light. Long speckled tails trail out behind. The olive head sits neat against the eye.

Fish it on flat, glassy water when duns are drifting and noses are breaking the surface. Cast a touch upstream, mend once, and let it ride drag-free. That white tuft stays easy to follow even in flat afternoon light.

Stripped quill is the part to get right. Soak it before wrapping, then lay each turn edge to edge so the dark band shows as clean segments from tail to thorax.

A coiled leader, tippet spools and an open fly box on slate

Rigging

Tippet
5Xhook size divided by three
Leader
Nine feet, tapered — longer and finer in flat water
  • Rig on 6X tippet, 9 to 12 feet, for a soft, natural landing.
  • Keep the CDC dry with a few false casts; avoid gel floatants on the wing.
  • Dead drift it and lift gently once it passes the rise to avoid spooking fish.

Where and when

Hatch
Olive mayfly duns, typically spring and autumn afternoons
Target
Trout, Grayling
Water type
Slow glides, flats and smooth runs
Also fishes
Also fishes well on slow spring creeks, still back-eddies and lake margins where duns drift on calm surfaces.

Make it yourself

Intermediate4 materials · 11 steps

Pattern
CDC Quill Dun
Style
Dry fly
Hook
Tiemco TMC 100size 16
Thread
Olive 8/0
Fly-tying materials laid out on a dark bench

Materials in the order they go on the hook

  1. TailCoq de Leon fibers
  2. BodyStripped peacock quill dyed olive
  3. WingWhite CDC
  4. HeadOlive 8/0 thread

Details

Imitates
Mayfly dun
Colors
Olive, White, Brown, Bronze
A fly-tying vise holding a bare hook on a wooden bench

How to tie it

The steps, from first wrap to whip finish (11)
  1. Mount the size 16 hook in the vise and start the olive thread behind the eye.
  2. Run a smooth thread base back to the bend.
  3. Tie in five or six Coq de Leon fibers, about one and a quarter shank lengths long.
  4. Tie in a soaked olive quill by its thin tip at the bend.
  5. Build a slight taper with thread toward the front third, then return the thread forward.
  6. Wrap the quill forward in touching turns, letting the dark edge form even segments.
  7. Tie off the quill a little behind the eye and trim the waste.
  8. Stack two white CDC feathers, tips even, and tie them upright at the front of the body.
  9. Post the wing upright with a few turns of thread behind it, wing height about one shank length.
  10. Build a small, neat olive thread head in front of the wing.
  11. Whip finish and trim the thread.
Proportions (4)
  • Tail: about one and a quarter times the shank length, fibers slightly fanned.
  • Body: covers the rear three quarters of the shank with a gentle taper.
  • Wing: CDC tips stand roughly one shank length above the body.
  • Head: a small olive thread bump, no wider than the front of the body.
Tips (4)
  • Soak the quill in water for a few minutes so it wraps without cracking.
  • Keep the thread underbody smooth; every bump shows through a quill body.
  • Even up the CDC tips before tying in so the wing stays full and upright.
  • Use light thread pressure on CDC to keep the fibers from flaring flat.
Common mistakes (4)
  • Gaps between quill wraps blur the segments; butt each turn against the last.
  • Crowding the eye leaves no room for the head; stop the body a few thread widths back.
  • An overlong wing makes the fly tip over; keep it close to one shank length.
  • Too many tail fibers look heavy; five or six fanned fibers are enough.
A dozen-fly materials kit laid out on slate with its recipe card.
The kit

Every kit size

Materials only

Size 16 · Materials only · 12 flies

$32.80

$2.73 a fly

Includes Tiemco TMC 100 · and 6 more

Every item in this kit · 7 items

Hooks & beads

  • Tiemco TMC 100$6.501 × 25 · size 16

Thread & wire

  • Olive 8/0 thread$2.951 spool

Materials

  • Other material: Coq de Leon fibers$4.501 pack · From the recipe row "Tail"
  • Stripped peacock quill dyed olive$5.951 pack
  • White CDC$6.951 pack

Finishing

  • Head cement$5.951 bottle

Guide

  • Printed recipe and tying stepsIncluded1

Size 16 · Materials only · 48 flies

$63.27

$1.32 a fly

Bought separately $66.60 · you save $3.33

Includes Tiemco TMC 100 · and 6 more

Every item in this kit · 7 items

Hooks & beads

  • Tiemco TMC 100$132 × 25 · size 16

Thread & wire

  • Olive 8/0 thread$5.902 spools

Materials

  • Other material: Coq de Leon fibers$92 packs · From the recipe row "Tail"
  • Stripped peacock quill dyed olive$11.902 packs
  • White CDC$20.853 packs

Finishing

  • Head cement$5.951 bottle

Guide

  • Printed recipe and tying stepsIncluded1

Size 16 · Materials only · 144 flies

$141.28

$0.98 a fly

Bought separately $160.55 · you save $19.27

Includes Tiemco TMC 100 · and 6 more

Every item in this kit · 7 items

Hooks & beads

  • Tiemco TMC 100$351 × 100 + 2 × 25 · size 16

Thread & wire

  • Olive 8/0 thread$17.706 spools

Materials

  • Other material: Coq de Leon fibers$22.505 packs · From the recipe row "Tail"
  • Stripped peacock quill dyed olive$23.804 packs
  • White CDC$55.608 packs

Finishing

  • Head cement$5.951 bottle

Guide

  • Printed recipe and tying stepsIncluded1

With vise & tools

Size 16 · With vise & tools · 12 flies

$182.80

$15.23 a fly

Includes Tiemco TMC 100 · and 15 more

Every item in this kit · 16 items

Hooks & beads

  • Tiemco TMC 100$6.501 × 25 · size 16

Thread & wire

  • Olive 8/0 thread$2.951 spool

Materials

  • Other material: Coq de Leon fibers$4.501 pack · From the recipe row "Tail"
  • Stripped peacock quill dyed olive$5.951 pack
  • White CDC$6.951 pack

Finishing

  • Head cement$5.951 bottle

Tools

  • Rotary pedestal vise$791
  • Ceramic bobbin$141
  • Fine-point scissors$161
  • Whip finisher$91
  • Hackle pliers$71
  • Bodkin$51
  • Bobbin threader$41
  • Dubbing wax$41
  • Canvas tool roll$121

Guide

  • Printed recipe and tying stepsIncluded1

Size 16 · With vise & tools · 48 flies

$205.77

$4.29 a fly

Bought separately $216.60 · you save $10.83

Includes Tiemco TMC 100 · and 15 more

Every item in this kit · 16 items

Hooks & beads

  • Tiemco TMC 100$132 × 25 · size 16

Thread & wire

  • Olive 8/0 thread$5.902 spools

Materials

  • Other material: Coq de Leon fibers$92 packs · From the recipe row "Tail"
  • Stripped peacock quill dyed olive$11.902 packs
  • White CDC$20.853 packs

Finishing

  • Head cement$5.951 bottle

Tools

  • Rotary pedestal vise$791
  • Ceramic bobbin$141
  • Fine-point scissors$161
  • Whip finisher$91
  • Hackle pliers$71
  • Bodkin$51
  • Bobbin threader$41
  • Dubbing wax$41
  • Canvas tool roll$121

Guide

  • Printed recipe and tying stepsIncluded1

Size 16 · With vise & tools · 144 flies

$273.28

$1.90 a fly

Bought separately $310.55 · you save $37.27

Includes Tiemco TMC 100 · and 15 more

Every item in this kit · 16 items

Hooks & beads

  • Tiemco TMC 100$351 × 100 + 2 × 25 · size 16

Thread & wire

  • Olive 8/0 thread$17.706 spools

Materials

  • Other material: Coq de Leon fibers$22.505 packs · From the recipe row "Tail"
  • Stripped peacock quill dyed olive$23.804 packs
  • White CDC$55.608 packs

Finishing

  • Head cement$5.951 bottle

Tools

  • Rotary pedestal vise$791
  • Ceramic bobbin$141
  • Fine-point scissors$161
  • Whip finisher$91
  • Hackle pliers$71
  • Bodkin$51
  • Bobbin threader$41
  • Dubbing wax$41
  • Canvas tool roll$121

Guide

  • Printed recipe and tying stepsIncluded1

The creator

An illustrated portrait for Dekasso (an illustration, not a photograph)

Dekasso

@dekasso

Wherever the truck rolls to a stop.

  • Tidewater Sundown Pale Ale — a river beer by Dekasso
  • Prairie Wildflower Portrait Trucker Hat — a trucker hat by Dekasso
  • Ember Golden Stonefly Nymph — a fly pattern by Dekasso

See everything by @dekasso

How it was made

3 iterations led here; the saved one is marked

  1. Iteration 1 of 31
  2. Iteration 2 of 32
  3. Iteration 3 of 33 Saved

Remixes

3 steps back

  1. Slate Ledge Grizzly Soft Hackle@dekasso · the original
  2. Grizzly Half Hackle Mayfly Dun@dekasso
  3. Evening Ember Sulphur Mayfly Dun — a fly pattern by DekassoEvening Ember Sulphur Mayfly Dun@dekasso
  4. Thistledown CDC Olive Mayfly Dunyou are here

3 remixes of this

Overcast Olive CDC Comparadun — a fly pattern by Dekasso@dekassoSlate Pool CDC Mayfly Dun — a fly pattern by Dekasso@dekassoBluebird Olive CDC Dun — a fly pattern by Dekasso@dekasso

Where this came from

“make it half hackle so there is only hackle above the body and it is trimmed below”

fly pattern · made

3 remixes

75 — from 3 remixes, at the Derby's published weights, since . Views are not counted.

  • cdc
  • quill body
  • mayfly
  • dun
  • dry fly
  • olive
  • white wing
  • coq de leon
  • trout
  • grayling
  • size 16