Last Saturday I bumped into the Lesser Scaup-like Aythya hybrid on the refuge at Wheldrake Ings. I was viewing from East Cottingwith. This bird was found earlier in the year at North Duffield Carrs but was usually distant. With closer views and better light it was interesting to check why we had decided this wasn't a Lesser Scaup in the first place. The features I consider to be anomalous with it being a Lesser Scaup and which are visible in these photos are:
1. Too much black on bill tip. On LS should be restricted to the nail and should not spread on to the sides of the tip. In addition the bill looks a little long and tapered to me.
2. The head shape is not quite right. While there is a good rear crown peak, the forehead is quite sloping and Pochard like.
3. The upperparts are finely vermiculated, not the coarse black and white vermiculations you would expect on drake LS.
If anybody had any further thoughts, please email me.