Start the tan thread around the middle of the shank.
Take two small pieces of mallard flank with the finest barring you can find and put them convex sides together. Bind them in about two eye-lengths behind the eye, judging the height so that when stood up they match a hackle one and a half to two times the hook gap. A couple of tight wraps, then snip the butts off behind.
Bring the thread to just behind the wings, pull them upright and take a few wraps up under them to prop them at about 90 degrees.
The bunched wings need splitting and setting slightly spent: two wraps running back to front on one side, then two wraps front to back on the other side.
Take the thread to the back and bind in eight or so black hackle fibres as a long tail, Catskill style. Snip the butts.
Wax the thread. Cut a small tuft of muskrat underfur, pull the guard hairs out and roll it onto the thread. Dub a fairly thin body forward to about two-thirds of the shank, leaving room for the hackle.
Tie in a black and a grizzly hackle together, barbs one and a half to two times the hook gap, with the grizzly on top so it wraps first. A couple of wraps, then a couple in front of the wings to secure both stems.
Wrap the grizzly two turns behind the wings and two in front for a grizzly-dominant collar. A couple of wraps to secure, then snip the stem before wrapping the black.
Zigzag the black hackle up through the grizzly, two turns behind the wings and two in front, and catch it off with a couple of wraps.
Whip finish, snip the thread, and singe any stray barbs crowding the eye.