Joern Lehmhus said:
Me also--more pics needed , I would say....
No more pics yet I'm afraid, and personally I'm very cautious of judging colour from photos especially in the extremely strong sunlight we're experiencing at the moment. That said, after a very long time carefully assessing the bird in the field (or rather, on the flash!) this morning, this is what I found:
Although the bird frustratingly refused to wing flap or stretch sufficiently to be absolutely positive on the wing bar and the distribution of white within it, on two very brief flaps (from poor angles) it did appear that strong white extended from the secondary wing bar to approximately P5 on the primaries and thus outside the expected pattern for Lesser Scaup. I can't explain why good observers have claimed a Lesser pattern originally and am holding out for better views for myself before I'm certain on this one.
The black on the nail can be very difficult to assess; sometimes appearing to spread slightly, but after good close views it appears the black is indeed restricted to the nail only. The bill shape and colouration is consistent with Lesser Scaup.
The head shape is perhaps rather un-Lesser Scaup like, lacking the peaked crown and small 'bump' on the rear crown so distinctive in Lesser Scaup. Instead it appears consistently rather angular and square shaped but not unlike some Lesser Scaups, although I would expect it to show some of the 'expected shape' sometime.
The bill often appeared very large for the head, although good in shape for Lesser Scaup and the whole appearance of the head and neck was perhaps too bulky for Lesser Scaup and not quite as 'delicate' as expected. On reference to photos on the internet it seems the relation of bill to head size in Lesser Scaup (and other aythya probably) is variable.
The sides of the head displayed a noticeable greenish sheen which seemed consistent most of the time, with a slight purple sheen appearing much less obvious and more prominent only from certain angles.
The vermiculations on the fore scapulars appeared very faint, with the same patterning on the rear scaps and mantle broader, darker and more obvious. Although the feathers appeared rather worn this might not be the expected pattern for Lesser Scaup but I have seen similar on birds in the states and on some photos on the 'net so am slightly cautious of placing too much emphasis on this.
On a rear view in direct comparrison to Tufted Duck in the same angle, the bird was considerably broader in body size (flank to flank) than Tufted Duck by approximately 30-40%. I cannot recall noticing this much size difference on Lesser Scaup before and would appreciate comment on this feature from those with a confirmed view. Otherwise, it's overall size (length of body/neck/head) appears pretty much similar to a drake Tufted.
It is currently being 'spouted' as a probable hybrid (including by the finder) but I find this difficult to swallow. Hybrid with what? Any Tufted Duck parentage would be expected to show more finely (and greyer/darker looking) back, some trace of a 'tuft' and a more extensive black nail atleast. Pochard would show a completely different suite of characters (bill, back, head shape, orange eye) and what of Greater X Lesser Scaup (which was mentioned to me today), this hybrid is unknown in the states and what chances of it here? If it wasn't for the squarish head and overall size (but what of overlap?) it appears to fit Greater Scaup quite nicely. Vermiculations, wing bar, head gloss, broad width of body, large bill size (subjective that though!) and although our knowledge of Lesser Scaups beginning the process of eclipse is poor I'm not sure it would account for most of these abnormalities.
An interesting bird and thanks to Rob for starting the concerns with his upperwing shot, I wonder the outcome had it only stayed briefly! Anyway, back tommorrow for another upperwing 'stakeout'!
Ian