Looking at the original Frank Sawyer Pheasant Tail Nymph you see a different look than many of the PTN’s today: no thread, more copper wire and no peacock herl.

Frank Sawyer's Original Pheasant Tail Nymph tied here by Tom Sutcliffe
Looking at the Pheasant Tail (Russian Artist Vladimir Fedot)

Tom Sutcliffe’s How To’s on Tying the Original Sawyer Pheasant Tail Nymph with some informative background.

 Also, check out the comment section for a fine video by Hans Weilenmann c/o Norm Frechette.