MZR'
If the pattern you say, "Is a streamer" and they're speaking of the "deer hair' that makes up the body............ from the hook eye/head, back past the bend of the hook, then the ONLY "deer hair" long enough to do that it of course is "bucktail deer hair".
If it's the actual "head of the streamer" they're talking about making, then it will probably be spun "deer hair body hair".
Streamers, as a rule don't float, so bucktail is the obvious choice, for the long body fibers.
Saint Paul-"The Highly Confused"
You cannot do a kindness too soon, for you never know how soon it will be too late.
-- Ralph Waldo Emerson