Actually its one I'd love to get on my patch at Ng Tung Chai.
It can be separated from the other warblers by its size, and long deep bill. The only warblers that come anywhere near in size are Thick-bileed Warbler, which is very rare, and at a push Manchurian Bush Warbler, but that has a rufous cap and smaller bill.
One more queston Guy - have you been keeping count of your Dollarbirds? This has been a recod autumn for me and I noted that you have been recording regular passage. It would be good to know how Geoff Welch or anyone else has done too.
Cheers
Mike K
Mike KilburnVice Chairman, HKBWSChairman, Conservation Committee