This journey into the intimate world of the structure of a duck's ass feather. The duck ass feather (CDC) is used for making many artificial flies in Europe. Henri Bresson and a few tiers from the Swiss Jura were the first to build artificial flies with duck ass feathers.
The duck ass feather is gradually replacing the Léon or Limousin hackles. CDC flies have a lower hold on the water than flies constructed with classic feathers. They have a great success on increasingly polluted contemporary waters where surface tension no longer allows insects to adopt their usual attitudes. They are stuck in the film of water and they have difficulty emerging from it. They find themselves tackled during their drifts. Their new silhouettes can be perfectly imitated with artificial CDC flies that mix with surface tension bubbles.
These feathers are produced near the oil gland located on the duck's rump. This gland secretes an oily sebum which the bird impregnates all the feathers of its body, smoothing them to protect itself from water and cold. CDC's feathers are therefore naturally coated with grease and waterproof. The microdroplets of fat are distributed in the many barbules that make up the feather.
The CDC feather is very full and vaporous. Each barb has a spiral architecture which increases its contact surface with the air. Each spiral can capture several micro air bubbles. Thousands of spirals, thousands of barbs and barbs trap thousands of air bubbles that accentuate the shine, increase the buoyancy of a waterproof CDC feather.
The CDC feather is made up of a central rachis from which many barbs start, bearing more or less dense barbules. It can be long and dry or short and greasy. All have very specific uses. The duck ass feather can have different natural colors (dun, khaki, gray, brown, white) with more or less pronounced tones. They can be tinted, but they change during chemical treatments. They become drier, more fragile or even brittle. They lose their barbules and their fats. You really have to use good quality feathers at the start to have good results after the treatments.
I use the head of the feather to make caddis or crane fly wings, the flank beards to imitate the wings of mayflies, caddisflies, mercantours, the spines to build legs, antennae, prothorax, heads .
All is good in the pen of CDC!