Scaup Identification!

OK! Dr. O’Shea at Ask a Naturalist at the NC Museum of Natural Sciences sent me this reply to my query if the flock of birds I had posted were Greater or Lesser Scaups: “Those are Lesser Scaup. Greaters do occur inland on the larger lakes, but it would be unusual to see so many away from the coast. Head shape can be a useful field mark, but not on flying birds. Fortunately these photos show the wing stripe very well. On a Greater Scaup, this stripe extends farther out into the primaries.”
Today’s photo is the same flock (I submitted 2 photos to Ask a Naturalist), and, it is easier to see the field mark in this photo that Dr. O’Shea says makes the identification of Lesser Scaups.
BTW: if you need help with an id of a bird, or animal or amphibian, plant, etc. here is the link to NC Museum of Natural Sciences Ask a Naturalist

lesser scaups