Scaups are tough for me, and this one has had me waffling back and forth between greater and lesser for a week. This was taken in south-western OR a few days ago (Grants Pass area) at my favorite birding park. We get both Greaters and Lesser wintering here, though the former is usually outnumbered about 6-1 by the later and relatively uncommon. The ruffled "tuft" of feathering at the back of the heard should indicate Lesser, but the large bill and forehead shape just give me Greater vibes. There were about 6 Lessers there that were clear to ID, but this one has perplexed me. Anyone able to help me settle?