Hi Cherry,
Woo, new bird for fung yuen! Thanks for your finding.
Where did you find it? Could you describe the location? Finding in bird flock?
The best bird for fung yuen in winter 08-09.
Agree with John, only Grey-crowned or Plain-tailed to be fit to this warbler.
However, do you have more photos on the head and the bill.
Thanks,
George