It is hard to tell with the picture you posted because it looks way to orange. However, it looks like a Merganser flank feather to me. Although the Merganser flank feather is a rose-tan color (thus my comment on the color geing too orange in your picture). The vermiculations on the feather also point in the direction of Merganser flank.
Merganser flank is a very good spey feather, especially used as a collar or face hackle.