American Herring Gull (smithsonianus)

(last update: October 12, 2015)

American Herring Gull (smithsonianus) 2cy (2nd cycle), October 12 2015, Weaver beach - Madison, CT. Picture: Keith Mueller.

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Complete moult almost finished (P10 has to grow about an inch), now 2nd gen (outer) primaries. P10 without mirror. Greater coverts are 2nd gen, with extensive dark brown centres. Old 2nd gen lesser coverts are worn and paler parts bleached to white.

After the complete moult, a limited 'partial autumn moult' can be started, in many birds. Here, this partial moult is quite extensive: the upper tertials have been shed and grow new again (now 3rd gen), as well as inner GC, almost complete row of MC and inner LLC. These new 3rd gen feathers contrast with the older worn 2nd gen coverts and often show less well defined patterns (more like adult feathers, but not necessarily). Easiest way to separate them is by the state of wear, especially in the central wing-panel.

Bi-coloured bill, dark iris are good pointers to age these birds. Note all black tail and very densely dark undertail coverts.