This bird was observed at Mai Po 20 Feb 2011. Since it was rather reddish looking I thought it was a Manchurian Bush Warbler at first. But it seemed too small and the call notes sounded like a Dusky Warbler. Yet the bill shape and bill color seems to fits Radde's Warbler (which can have a call similar to Dusky Warbler)--so I think it is a strangely reddish colored Radde's Warbler.