Kentucky Ornithological Society
Comparison of Lesser and Greater Scaup
Photos and text by David Roemer
Images A-F are of a pair of male Lesser Scaup present at Griffin Park in Bowling Green on 8 and 9 January 2007.
Images B and C show the typical Lesser Scaup head shape with pointed rear crown and how head color can vary from purple to green gloss depending on angle.
Image D is a close-up showing head detail.
Images E and F depict how head shape can change with attitude. Lesser Scaup typically compress their head feathers when feeding eliminating the peak to the crown which gives them a totally different appearance. They may also do this when alert or threatened. They can appear very similar to Greater Scaup when assuming this attitude, particularly when showing a green gloss to the head.
Images G-J were obtained at a slough along the Ohio River in Henderson County on 21 March 2007. These images are of a mixed flock of Lesser and Greater Scaup.
Image G is of a male Greater Scaup on the right with male Lessers, all with a relaxed attitude showing typical head shape and gloss. The Greater's slightly larger size, rounded and proportionately larger head, and overall cleaner appearance can be seen.
Image H is of 2 male Lessers on the left and 4 Greater Scaup. The proportionately larger heads of the Greaters are apparent.
Image I has 2 male Greaters present, at the center and far right. The larger size, rounder and proportionately larger heads, and overall cleaner appearance can be seen.
Image J shows a female Greater Scaup second from right. Her proportionately larger and deeper bill can be seen. A male Ring-necked Duck is also present.
Images K and L are of a male Lesser Scaup present at Griffin Park on 9 December 2005. The white wing stripe does not extend strongly into the primaries.
However, the primaries are paler than and do contrast with the darker coverts. Of particular interest is the head shape. Notice that the head feathers are compressed and the peaked rear crown appearance is no longer evident.
Images M and N are comparisons of the scaup species in flight and are of the same flock as in images G-J.
Both images contain a male Greater Scaup in the center, and image N has a male Ring-necked Duck on the left. The white wing stripe extends strongly into the primaries of the Greater, evident from above and below, and with more contrast between inner and outer primaries than in Lesser. The primaries of Lesser are more uniform overall, and the inner primaries contrast less with the dark upperwing coverts than in Greater. The proportionately larger head, deeper bill, and steeper forehead of the Greater are evident. None of the Lessers show a high peaked rear crown that is usually evident on resting birds.
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