I have always assumed that large rafts of Scaup sp. along rivers in Oregon were almost entirely LESSER SCAUP (e.g. Scaup flock off Marine Drive at PDX airport, Dean Creek Wildlife Area east of Reedsport) and I have confirmed that first-hand while stopping to scan through these flocks. As I was driving along the Columbia River around the Biggs area in Sherman County yesterday, I assumed the large raft was also predominately Lesser Scaup, but in fact, when I scoped the flock, I estimated 80% of the 1000 birds were GREATER SCAUP. Perhaps this is not news to old time Oregon birders, but I was surprised.