Lesser Scaup vs. Greater Scaup vs. Ring-necked Duck

These three species of waterfowl are tough to tell apart and can often be found together. Ring-necked Ducks are the easiest to tell apart from the other two but this distinction can be challenging for beginners. Below is a table of the three species with characteristics of each. These characteristics apply to both sexes unless the parenthesis after the characteristic indicates otherwise (M = male, F = female). These characteristics should be used in unison and a confident identification should be made only after minutes of study – probably with a scope. Many of these characteristics can change depending on a number of conditions. I find that the most helpful and consistent characteristic to tell the scaup from one another is the head shape, but other characteristics should also be considered. I hope this helps!

Characteristic Lesser Scaup Greater Scaup Ring-necked Duck
Bill Gray-blue with typically narrow black nail; smaller Gray-blue with typically broad black nail; longer Gray-blue center with white outline and black tip
Size Smallest Largest Intermediate
Head Shape Narrow; peak at back (only when resting); tall Broad; rounded; low Peak at back
Side/Flank Coloration (M) Dirty white Clean white Gray with white spur at front
Head Color (M) Typically purple iridescence Typically green iridescence Typically purple iridescence
Head Color (F) Usually less white at base of bill; brown cheeks with pale spot at back Usually more white at base of bill; brown cheeks with pale spot at back Gray cheeks and white eye-ring
Wing Pattern (in flight) Usually more contrast between white secondaries and grayish primaries White usually extends further from secondaries into primaries Gray primaries and secondaries
Back Color (M) Grayish Grayish Black
Habitat Typically winters inland lakes and reservoirs and also likes coastal bays and open water; increases in domination as you travel south Found more often on coastal bays and river inlets and farther north Typically still, sheltered freshwater