The Tower Road phalarope appears to have a streaked back because it is molting from juv to basic plumage (using terminology no longer in favor, here, but widely understood)
Indeed, using back pattern on phalarope is fraught with problems, as basic adult RN Phalaropes (of which I've seen some this fall) can appear totally gray backed (and with limited black markings on head), much like a Red Phalarope.
And as the photo from Tower Road shows, juv Red Phalaropes in molt can appear striped
Good Birding
Steven Mlodinow
Longmont CO