Greater and Lesser Scaup can be challenging to identify. Seeing the two together makes the differences between them easier to compare. On January 25, I saw and photographed an adult male Greater Scaup with an adult male Lesser Scaup inside Montrose Harbor. The photo nicely shows the main differences, namely the fuller, more rounded head of the Greater and the narrower, more pointed head of the Lesser. Also note the purer white sides of the Greater compared to the grayer sides of the Lesser. If you get the chance to compare two similar species side by side, take the time to study them closely. More photos of these birds are at my eBird checklist for the day, URL below.
January 25, 2021