Larus fuscus fuscus 3CY, December 06 2013, Ashdod, Israel. Picture Amir Ben Dov.
Bird in active moult, probably Staffelmauser; illustrative bird to explain the presence of moult divisions in returning birds in spring.
3rd gen tail. 3rd gen secondaries.
Presumed moult stage: P1 new, P2 growing. P3-P6 fresh, P7 missing/growing (note the distance in the step between P6-P8, and see tip of P7 in right wing, 2nd image), P8-P10 old (probably 2nd gen lacking mirror on P10). If this presumed moult stage is correct, it may help explaining moult divisions in returning birds in spring (about 5 months from here): if the moult in the outerwing continues up to P10 these outer primaries will appear quite fresh in spring, with P10 fully grown approximately by February. This is also the time span which will take the inner moult wave (now at P2) up to P6 or P7, maybe P8. It seems logic to conclude the wear and condition between the feathers on both sides of the moult division will not differ much, with the outer feathers only slightly older than the very fresh last feather replaced in the inner moult wave. And this is exactly a pattern we seen in many returning fuscus fuscus in spring, especially in3CY but also in some 4CY birds. E.g.: 3CY KJX7, C10H, 4CY HT221339.