Great find Kitty and wonderful photographs!
Brendan I have to disagree about the tail. Hawfinch has a very short forked tail, which these pictures show reasonably clearly albeit from a side view. Indeed both the wings and tail look to be in excellent condition to me - while a HKU PhD study of the bird trade showed that some 95% of cagebirds show damage.
In my opinion both this bird and the bird I saw today in Lam Tsuen (which may actually be the same bird) add greater weight to the case that Hawfinch does indeed as far south as Hong Kong as a genuinely wild bird.
Cheers
Mike
Mike KilburnVice Chairman, HKBWSChairman, Conservation Committee