I think this is a winter plumage male, which is unusual. Presumably, brought in by the cold front.
It was certainly very hungry, but unfortunately was disturbed by two groups of walkers and flew off, I couldn't refind it.
These buntings make a soft 'quip' call, quite different to the normal harsh bunting call.
After four years without seeing one, this is the second Black-headed Bunting on Po Toi in 2 weeks.
A good start to 2010.
Welcome to HKBWS Forum 香港觀鳥會討論區 (http://www.hkbws.org.hk/BBS/)