Just missed this thread - the disucssion on WBSE.
Without doubt, this bird is born last winter 09/10, which means it's around 14 months old, whatever you called it.
Please note that the term "first winter" are generally refer to the migratant from Palearctic or those normally breed in spring/summer. But WBSE in HK, also in Australia, breed in winter. So, I don't know what exactly "first winter" means for this species..
This bird arpparently has not yet attained sub-adult plumage, is something in between "fledgling" and "juvenile", depending how you call it.
There has been a short note published in HKBWS Bulletin with drawing (2009 winter edition or around) explaining how to age WBSE.
By the way, a good photo set and WBSE juvenile record.
Gary
