Cul-de-Canard (CDC) Puffs, grouped CDC feathers, are are sometimes called nipple plumes because on a live bird, they are located on the nipple of the preen gland. Tied in as wing posts, these fluffy feathers trap a lot of air. The CDC Bubble is meant to float the fly in the surface film. The CDC feathers bring the fly to life if it sinks slowly in a vertical position through the water. Tying flies for fly fishing in New Zealand using CDC (Cul de Canard) feathers creates superb flies when it comes to tying flies with captivating and subtle movement in the water. Ideal for many fly types from emergers to simply adding movement to larger streamers.