What it is
Cul de Canard, or CDC, is the small duck feather that carries natural preen oil. That oil makes the fibers water repellent, and the feather traps tiny pockets of air, so it rides high when you want float and can still look alive when it’s just under the surface.
What to tie with it
Most tyers reach for CDC when they need a wing on emergers, dry flies, terrestrials, and spinners without adding bulk. You can also spin it in a dubbing loop for buggy, mobile fibers, or wrap it as a buoyant body. On nymphs and emerging patterns, CDC helps create that “trapped air” look that suggests an insect trying to break through the film.
Flies and the fish they're for
CDC shows up in patterns like the CDC and Elk, a classic dry that’s fished on trout water when fish are feeding on top or in the film. More broadly, CDC-winged emergers and spinners are go-to choices for trout in rivers and spring creeks where insects are hatching and the takes are subtle. Because it floats well but still looks natural when damp, it fits situations where trout key on delicate, half-in/half-out presentations.
How it compares
Compared to CDC Oiler Puffs, these are the standard CDC feathers, while Oiler Puffs are smaller and better suited to smaller flies. Polypropylene Floating Yarn can give a similar look and buoyancy, but CDC covers more jobs at the vise, from wings to looped bodies and nymph accents.
