The discussion over the origin of this bird prompted me to see for myself. I found her on the bank about 30m upstream from the village house. She was somewhat obscured by vegetation so after watching from the bridge for a while I then went into the bamboo clump beyond the bridge which allowed me to get closer. This was quite a noisy affair and she became alert but did not try to hide or show any indication of flying. In my view based on experience in mainland China such tameness is atypical. I also find it somewhat strange that she has remained on such a short stretch of river for so long.
I'm not saying that I am sure that this is an ex-captive bird, but if I had to choose one way or the other I am afraid that I think that this is more likely than not.
Cheers
Mike Leven