This is a very lively nymph, alive with motion even when it's sitting still.
Hook: Mustad 9671 (2XL wet fly), 8-14
Tail: Grouse filo
Body: Grouse filo
Thread: Black monocord
This one is simplicity itself. Tie in the foundation smoothly along the entire shank and cement, tie in one grouse filo as the tail and two as the body. Wrap the thread forward to the eye, then wrap the filo forward, wrap down and trim excess. Finish with a wrap knot and cement head. That's all, folks.
The attraction to this nymph, like the marabou nymph, is the action of the feathers, creating motion with the slightest action, just like many aquatic insects. It can be fish at a dead slow creep or moved quickly in a swimming action. It lends itself to almost any style that one can fish a nymph. It can be weighted if desired and fished deep. It can be fished in the open or around structure. Moving water is no problem, just be sure to tend the line properly.
As lack-luster as this fly may seem to the angler, it's a high level attractor to the fish. Be ready for a strike at any time from any number of insect eating fish.