Mount hook, start orange silk or thread behind the eye and wrap a slender body back to the bend and forward again. Two thin layers, no lumps. Real silk darkens translucent when wet; that's the traditional magic.
Optional: 4 turns of fine gold wire rib.
Select a well-marked partridge back feather, fibers about one and a half shank lengths. Tie in by the tip.
Wrap 1-2 turns, no more. Sweep the fibers back so they cage the body like an umbrella blown inside-out.
Tiny head, whip finish.
Substitutions
Body instead of Orange silk or floss: Orange thread wraps — Simplest approach; Orange dubbing (sparse) — Slightly more texture
Hackle instead of Partridge back feather: Hungarian partridge — Same thing, different name; Hen hackle (brown) — Softer, less mottled; Starling — Darker, very soft; Brahma hen — Natural barring