The soft, grey coloured fibres of cul-de-canard make a perfect material for winging a variety of Stillwater dry-flies — not least those imitating upwing species such as the pond olive and lake olive. This pattern, the aptly named CDC Dun, combines the properties of CDC with a thorax-tied hackle to produce a pattern to fool the most educated trout feeding on freshly emerged olive duns.
The use of a hackle tied in open turns over the thorax works extremely well in patterns of this type. The aim of the technique is to distribute a relatively small number of hackle-turns over as large an area as possible. The result is much sparser than is possible with a close-wound hackle, producing a lighter, more natural looking “footprint” on the water’s surface. Also, to help the finished fly alight in the right position after casting, the hackle fibres beneath the hook are normally trimmed off.
To keep the body in the correct attitude the hackle-fibre tails are tied as outriggers again so that, like the hackle, they present as large a surface area as possible while keeping the number of fibres to a bare minimum.
Tied with a slim body of dubbed fur, the CDC Dun can be tied in a range of olive shades to imitate not only pond and lake olives but other species such as the bluewinged olive.
Hook Size 14-16 down-eyed dry-fly
Thread Olive Tail Blue dun hackle fibres
Body Medium olive SLF Finesse or
similar Thorax Medium olive SLF
Finesse or similar Hackle Blue dun cock
hackle Wing Natural grey cul-de-canard
1. Fix the hook in the vice and run tying thread, in close turns, down to the bend. Wax the tying thread lightly before applying a minute pinch of olive dubbing.
2. Gently twist the fur on to the thread so that it forms a short, very thin, rope. Wind this on, slightly round the bend, to create a short tag.
3. Select a blue dun cock hackle, which can be either natural or dyed. This feather should be large with long, straight fibres.
4. Remove four to six fibres and catch them in just in front of the fur tag. The tips should project past the bend a little less than the length of the hook shank.
5. Secure the tails in place then dub on a larger amount of the same olive fur. Make the first turn right against the tag. This will cause the tail fibres to splay out.
6. Carry winding the fur rope along the shank, in close turns, to form the body. Next, select a natural grey CDC feather with dense, fluffy fibres.
7. Take a second CDC feather, and place the two together so that their tips are level. Catch the plumes in at the front of the body. This wing should project just past the hook bend.
8. Prepare a blue dun cock hackle, with fibre-length one and a half times that of the hook gape. Catch it in immediately in front of the body and just behind the wing.
9. Take another pinch of the olive fur and dub in on to the thread. Wind it both to the rear and in front of the wing to form the thorax.
10. Stop the thorax just short of the eye. With hackle pliers, take hold of the hackle tip and wind on three or four open turns. Secure the tip at the eye and remove the excess.
11. Cast off the tying thread at the eye with a whip finish. With scissors, carefully trim away the hackle fibres beneath the thorax to leave them at the top and sides.
WHERE, WHEN & HOW TO FISH
W H E R E
Use this pattern when trout are feeding on the freshly emerged duns of both the pond olive and lake olive. During a hatch of the naturals the trout on waters ranging from large natural lakes down to small stocked waters can become preoccupied with this food form.
W H E N
The main periods to find both species hatching is around May and June with a second generation putting in an appearance later in the year, between late August and September. The nymphs live in water 6 ft-10 ft deep and generally emerge as duns during late morning through to early afternoon.
H O W
The CDC Dun should be fished on a floating line with a tapered leader of around 4 lb-6 lb breaking strain. It is normally fished singly, either cast to intercept an individual feeding fish or into an area where the naturals are being taken.
T Y I N G T I P
Use a tiny ball of dubbed fur, applied first, to keep the tails splayed into an outrigger position.