Interesting posting.
Numbers of Greater White-fronted Geese seem to be plummeting along the Yangtse. Paul Holt's reports from Poyang this winter show a peak count of 200 there, way down from the thousands that were formerly present.
Also, just to confirm, were the swans at Dongting Whooper or Bewick's (Tundra)? Whoopers seem to be very rare along the Yangtse.
Richard