Cover the shank with thread, then bring the thread back up to the front of the hook.
Select a bunch of elk hair about as thick as the hook gape when relaxed in your fingers, pull out all the underfur (it will absorb water and sink the fly), remove any reversed hairs, and even the tips in a stacker.
Tie the elk hair in at the front so the tips project forward over the eye as a single wing, wrapping backward over the butts to lock it in tight, then clip the butts.
Take the thread to the rear of the hook and tie in a sparse half-strand of grey Antron yarn as a trailing shuck; wrap forward over the butts to keep an even body diameter up to the thorax, trim the butts off at the front and trim the shuck itself to about a hook-gape long.
Tie in the grey goose biot by the tip at the rear with the convex side facing you, then take the thread up to the thorax area.
Grip the biot in rotating hackle pliers and wind it forward in touching turns to the thorax to build a segmented abdomen; tie it off gently. The biot is brittle and heavy thread pressure will cut it. A little head cement wrapped under the biot adds durability.
Spin a thin noodle of beaver, muskrat or otter dubbing on the thread and build a fairly full thorax. These furs are water-repellent, unlike rabbit.
Prepare the hackle by nicking a small cut in each side of the stem to leave tiny stubs for the thread to grip, tie it in, and take just three turns; bring the thread behind and tie it off.
Lift the wing, bring the thread in front of it, form a small head, add a half hitch to hold everything, then whip finish.