From Umpqua signature tier Antonio Rodrigues, the quill midge is a wise choice whenever fish are eating things on the surface that are too small to see. It's buoyant and visible but gives a small profile to the fish.
Here's what Antonio has to say:
"The thin body that a quill creates is a perfect imitation for midges and small mayflies. This Quill Midge uses the same CDC split wing with a high vis material which makes this very small profile fly visible at distance.
Born out of competition but intended to make any day of fishing better.