Photos on bucktonbirder's blog certainly seems to show a classic Pleske's Tit. Definitely not a pure Azure.
It's good timing for a Pleske's vagrant, but Azure, Pleske's and Blue are also kept in captivity, especially in the low countries (where Azure is more popular than in UK, where it's rare).
Dusky cheeks are the only slightly odd thing. I'm not an expert on southern Azures, but isn't this a feature that is more prominent as you get towards Yellow-breasted Tit? So potentially a southern-range hybrid than the more usual northern Pleske's?
Got to say I'm struggling with seeing any strong indications of Blue Tit in this bird, why is it not an south eastern race Azure/Yellow-breasted Tit?(I don't know enough about these races/species to comment to much). Yes the yellow on the breast is washed out but could that be explained by poor diet (perhaps in captivity and I believe this is already known in Yellow breasted, from a link on Birdforum?).
Can anyone point out any definite Blue Tit in the plumage as most hybrids I have seen in a cursory glance at photo's on the the net etc seem to show more pro Blue Tit Features? Of course there is the chance of 2nd or 3rd generation hybrids I suppose.....
The main pro-Blue Tit feature is surely the rather extensive yellow wash on the underparts. This seems more extensive than on any photos of Yellow-breasted I can find, but it's not easy to tell from the photo and this isn't a well-known species in terms of variation (neither are the more southern races of Azure). That head pattern is quite good for Yellow-breasted though, isn't it? If it's real, of course - I've heard that the bird looks 'gleaming white' in the flesh.
Gotta say, though, after hitting the books I think either a pure Yellow-breasted or hybrid Yellow-breasted x Blue is maybe more likely than a Russian Azure x Blue.
Pleske's Tit just refers to a hybrid Azure x Blue, and seeing as Yellow-breasted is sometimes treated as conspecific with Azure then it may well still be a 'Pleske's Tit' of sorts.
Major problem is that of back-crosses, according to Harrap & Quinn, as even 1st generation hybrids are extremely variable. Yellow-breasted and Azure are bred in captivity in Europe and here, so it might be a new escapee, or a hybrid from an escapee parent either here or somewhere like Holland, or it might be a wild 1st, 2nd or 3rd + generation hybrid from Russia etc. Take your pic!
Not sure how people are managing to age it, or work out moult, based on phots doing the rounds - can't se anything certain myself.
Last edited by mafting; September 15th, 2011 at 08:31 PM.
Just had a brain-wave - if it's decided that it's a Yellow-breasted Tit, then it is legal to catch it and take it back into captivity. An easy £250 for a lucky ringer!