The characteristics of CDC (Croupion De Canard):
Light and soft material.
Tough and strong fibers.
Semi-translucent; flies tied with CDC have a more life-like quality than flies tied with other, more opaque materials. The CDC flies are less opaque than other artificial assembled with materials that do not let the light through
Highly aerodynamic; when cast, the CDC collapses but, at the end of the cast, it expands acting as a para chute as the fly descends to the water. It therefore makes casting easier and fly presentation more delicate.
Highly hydrodynamic– under water every filament pulsates with life even in the gentlest flow or on the slowest retrieve.
Each fiber vibrates and gives a pulsatile fly, who "lives" and comes alive in the slightest movement.
Folds like real fly tissue when a fish takes a CDC fly into its mouth. In this way fish accept CDC flies more readily, and are much slower to reject them, than ones made of harder materials.
Warning: Colors #1 to #6 and #8 to #16 feather lengh: 3 to 6 cm; color #7: 1.5 to 3.5 cm