Tying with CDC
Many birds preen, recondition, and waterproof their feathers with an oil secreted from their preen (uropygial) glands. CDC feathers sit on top of the gland and the area close around it. While CDC is normally harvested from members of the duck family ("canard" is the French word for duck), other waterfowl such as geese offer similar quality feathers. As the size of the bird increases, so will the size of the feathers. The description "Cul de Canard" was reputedly coined in the late 1950s by French tier Henry Bresson for one of his patterns.
CDC's history in fly tying and fly fishing begins in central Western Europe in the 1920s and the dry flies used by fishermen living in the Swiss Jura Mountains near the French border. These patterns, generally referred to as Moustique patterns,
By the late 1980s the first signs of CDC in North American contemporary fly tying became visible RenĂŠ Harrop's landmark article in the July 1991 issue of Fly Fish and helped popularize CDC in the States. Another prominent who was instrumental in developing techniques and patterns using CDC was Colorado tier Shane Stalcup.
Zooming in on the CDC feather structure the stem shows, besides the barbs, jagged protrusions. The barbs in turn sport ribbon-like twisted barbules. Flattened barbules maximize the surface area. In the surface film, a larger and water repellant surface area assists floatation of the dry CDC pattern.
Zooming in even more, this illustration shows a submerged CDC feather. The ribbon-like and twisted barbules retain tiny bubbles of air which adds buoyancy to the CDC.
Type 1 This feather resembles a partridge body feather. The feather has a rounded tip and a fairly short, tapered stem with barbs set at approximately 60 degrees from the stem.
Type 2 This feather has a thin stem and the barbs run mostly parallel to the stem, ending in a square, brush-like tip.
The nipple plume, sometimes referred to as an oiler puff
Type 4 This feather has a long stem with relatively short barbs. Shop-bought bulk packages mostly hold Type 4 feathers.
Tying with CDC