Fortunately, when we got there it wasn't too far away, although the light conditions were dreadful. It was relatively easy to pick out but was diving almost continuously, only staying on the surface for a few minutes, and staying under the surface for a long time.
This was not the most colourful of individuals. It was obviously a Scaup due to its very rounded head, larger size than Tufted Duck and the grey starting to show through on the mantle. The grey on the mantle points to this being a male bird and therefore, at this time of year when adults should be more advanced in their eclipse plumage, a first winter bird. The first photo gives a good size comparison with Tufted Duck.