HOOK: TMC 100, sizes 16-20
WING: Deer hair, dyed gray. When done tying, flare the wing so it forms an upright semi-circle over the fly.
TAIL: Tan Z-lon, not too thick
BODY: Pale yellow Superfine
Imitates a hatching mayfly dun. Use during a hatch when the duns are on the water and trout are feeding on them.
The Sparkle Dun is one of the most useful styles to learn to tie. It is not a difficult pattern to master, and it catches fish. Essentially, the fly is a Comparadun with a Z-lon tail that represents the shuck the dun has just emerged from. It's a clever and deadly variation.
Why does it work so well? Because a dun that has just emerged from the shuck has to dry its wings before it can fly off; thus, it will be on the water for the maximum amount of time. If you were a trout, which mayfly dun would you prefer: one that might fly away before you sip it down, or one that is guaranteed to still be there after you spend the energy to reach it?
A useful variation is the CDC Sparkle Dun, which uses CDC fibers for the wing. This latter variation is sometimes tied with a mallard flank wing in front of the CDC, but I don't think the trout care if the mallard flank is there or not.
This dressing imitates a hatching pale morning dun. To imitate other mayfly duns, vary the size and color.
How to match other mayfly duns
How to Fish
Dress the fly with floatant and use standard dry fly presentations.