Varied Tits have not previously been noted to migrate any distance whatsoever. That doesn't, of course, rule out the possibility that they are migrants (a comparable example would be owstoni flycatchers, for which the first evidence of significant migration concerned birds in HK). Although there may well be no evidence of previous captivity, equally there is no evidence of previous migratory behaviour. My current feeling is that the case for either scenario is not strong, and so a cautious approach may be the most appropriate. If this bird, and the Zhejiang birds, do indicate previously unrecorded coastal migration, then it will happen again, and we can base a judgement on stronger evidence.
GeoffC
