I can't see anything on this bird that would rule out taimyrensis
, and superficially at least it looks much like the birds we get here. In fact, the head/nape streaking (a cluster of streaks on the nape and a 'dusting' around the eye) looks spot on for many at that time of year, as do the fresh-looking but rather smallish apical spots on the (presumably recently replaced) primaries. (Both of these features would rule out any YLG influence, no?)
The only thing that does look odd to me is all that bulk. The 'best' taimyrensis
(and I hesitate to use the word 'typical') are on the slender side, with long-looking wings; your bird seems a bit 'brutish' to me. However, the first bird in my last post above (#128) looks similarly 'brutish', so I guess your bird still falls within range.
I've added a few more late Feb/Mar photos of taimyrensis
. The first photo shows the 'best' taimyrensis
(with its long wings), and these structurally don't look much like your bird. The last photo shows a collection of mostly taimyrensis
(with all its variation), some of which do look a lot more like your bird!
As Yoav says in the original thread, though, it would be nice to have an open wing to look at, and I don't know how much further you could go with this bird without that!
No help whatsoever, then, in the end!