This bird is a male White-shouldered Starling.
The colour rings are part of a project being carried out by the hong Kong Ringing Group into the local movements of this species.
The combintaion on this individual show that it was ringed as a chick in the MTRC mitigation wetlands at Lok Ma Chau in 2007. It was also photographed at Mai Po a couple of weeks ago:
http://www.hkbws.org.hk/BBS/view ... &extra=page%3D1