The uniform brown 'sjawl' and the pattern of the tail-coverts; traces of brown and black in the wing coverts and tertials; distinct primary pattern with broad black band on P5 and white mirror on P10; and the tail band in this bird gave a smithsonianus impression.
3rd-cycle is a very tricky plumage and it is thus vital to look at the whole plumage with a critical eye. Details like the tail and secondary pattern are crucial, and unfortunately do not look typical for smithsonianus in this one.
|Note that the dark in the tertials is blackish as in smitsonianus rather than brown as often is the case in typical Herring Gull|
|The new (grey) mantle feathers are slightly paler than on the nearby argentatus which was also the impression when it was seen together with other adult and near-adult argentatus|
|Densly dark-patterned hindneck, creating solid dark necklace|
|Note extensive blackish-brown in tertials, only with vermiculation at the tip|
|Barred undertail coverts. Thin barring on the tail coverts in a 3rd-cycle Herring Gulls indicate a northern origine such as Iceland|
|The hindneck shows rather plain and smooth streaking (usually a lot of longitudinal streaking in typical argentatus)|
|Scattered smudging across breast from nape ...|
|... and dark smudging on the belly|
|New innner primaries strickingly paler than greater coverts as in smitsonianus and argenteus, but more rare in argentatus. Note also white mirror on P10|
|The secondaries are irregularly vermiculated brownish as in European Herring Gull and lack clean black as in smithsonianus|
|Note discrete dark brown marks on secondaries. The greater coverts of 3rd winter smithsonianus are not usually this coarsely barred, and the same is true for the tertials|
|Note that tail is still rather heavily marked, however, in smithsonianus the tail usually looks a bit more solid black than this|
|Sooty tipped underwing coverts and white armpits|
|Note that there are a few barred uppertail coverts|