nominate Lesser Black-backed Gull (L. f. fuscus)

(last update: 26-2-2011)

Larus fuscus fuscus 2cy, March 25 2011, Ashdod, Israel. Picture Amir Ben Dov.

Very interesting bird, revealing a bit of the moult startegy on the wintering grounds. One of the main questions regarding this moult is "How do 2cy fuscus manage to moult a complete cycle in such a short time?" Just have a look at the February section, to find birds largely in juvenile plumage (except the scapulars). Especially replacement of the large primaries takes several months in the complete moult in argentatus and graellsii in summer. Still, many 2cy fuscus appear with a complete set of 2nd gen primaries in Finland in May.
One explanantion could be that there are different birds involved. For instance, late moulting birds remain in Israel, while advanced 2cy fuscus migrate directly from Africa to N Europe. Another explanation could be an adjusted moult strategy, illustrated by this individual. If you start moulting primaries at two locations (Staffelmauser!) the moult cycle can be reduced in time.
Here, P1 is new, P2 is growing, P3 is missing, P4 is still juvenile, P5 is growing, P6-P10 still juvenile. Here you see a possible start of a double moult wave in the primaries. Moult in wing coverts and tertials follow a timing that is quite common in graellsii. The inner 5 greater coverts replaced and central gc growing, closing the gap in this tract. Juvenile wing-coverts can still be found in the carpal edge.
The tail seems to be completely renewed, but all secondaries are still juvenile.