I do NOT expect anyone to identify a sora from this photo, but the blur within the blur is actually the bird. I saw it well enough in flight to note the size and stubby yellow bill. Prior to flushing, I was on the boardwalk after a rain (so there was no to minimal human activity for an hour or move) and saw something move the reeds a few feet away. There was too much vegetation to see what it was, but after ~30 more seconds, it flushed to the other side of the boardwalk.
from auto tour route
The Sora (Porzana carolina) is a small waterbird of the family Rallidae, sometimes also referred to as the Sora Rail or Sora Crake.