SOLWAY: American Wigeon?

Here's a post I've been holding back for a few days:

22 December: After a quick look from the Mersehead RSPB reserve centre we headed to the Brauich Hide stopping to watch the Barnacle Geese and a couple of Bullfinches on the way. There were plenty of ducks on the wetland, mostly Teal and Pintail with a sprinkling of Wigeon. We were just about to leave when I decided to give the marsh one last scan with the 'scope and spotted an unusual wigeon. It was in the company of several Eurasian Wigeon at first but frustratingly made its way to the back of the wetland with some Teal. The conditions were getting progressively worse but the grey head with bottle-green mask and pale crown stripe were obvious as were the orange-chestnut flanks. I rattled off a series of what I knew would be "record-only" shots in the poor light feeling quite convinced that we had an American Wigeon. My only concern was that at some angles the crown stripe showed a yellowish wash (rather than cream) even in the poor light so the dreaded hybrid theory raised its ugly head. After parting from the Wigeon and Teal and swimming around alone for a bit it suddenly took flight towards the Meida Hide in the distance. Even in the now misty conditions the white "wing-pit" was obvious but I lost the bird in the murk at the back of the wetland.

Making our way to the Meida Hide we could barely see more than a couple of hundred metres and it was no surprise that I failed to relocate the bird so we called it a day as visibility worsened. We alerted the reserve centre staff about "a drake with at least some American Wigeon in it".
The sky was clearer inland as we headed towards Dumfries so we pushed on to Lochmaben where we saw the drake Long-tailed Duck but no sign of the Smew in the late afternoon.

So, what about the American Wigeon then? It looked pretty good in the murky conditions at the back of the lagoon, didn't it? The top photo hasn't been changed at all apart from a bit of cropping to highlight the bird. But when the bird started to swim away just before it flew the crown stripe appeared a different (more yellow) colour. We never saw it again unfortunately.