What it is
Hareline CDC Oiler Puffs are CDC oiler puff feathers taken from duck cul de canard with the natural preen oil still coating the fibers. That oil helps them shed water and stay naturally buoyant, so they float well on the surface and keep a lifelike, breathing look. In the water the fibers trap little pockets of air, which is useful when you want an insect-y “air bubble” effect.
What to tie with it
Use them as wing material on emergers, dry flies, terrestrials, and spinner patterns, either as a small puff or a more pronounced wing. You can also strip fibers into a dubbing loop and spin them for a shaggy collar, or wrap the fibers as a buoyant body when you want a lot of movement without adding bulk. They also fit nymph designs where you’re trying to suggest that trapped-air look.
Flies and the fish they're for
CDC and Elk is a classic dry fly application, fished for trout on rivers and spring creeks when fish are looking up for adults. The CDC Puff Daddy style midge patterns are tied and fished for selective trout on technical water where a little extra softness and float can matter. CDC-based BWO and blue quill emerger patterns commonly use puffs for the wing, and those are trout flies for hatches on freestones and tailwaters.
How it compares
Polypropylene Floating Yarn can give a similar look and buoyancy, but it doesn’t cover as many tying jobs as CDC does, especially when you want that soft, airy fiber behavior. CDC’s range from winging to loop-and-wrap applications is broader.
