nominate Lesser Black-backed Gull (L. fuscus)

(last update: 7-5-2006)

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(2 images) Larus fuscus fuscus 2cy, July 12-14 2003, Tampere, Finland (61.33N 24.59E).

In all respects an average 2cy fuscus in Finland in July, with very blackish brown fresh coverts and scapulars, but with the primaries P4-P10 still juvenile and P3 missing. PrimariesP1-P2 are second generation. Probably the primary moult commenced in Scandinavia. All tail-feathers are fresh second generation, probably replaced on the wintering ground.
The scapulars show a mix of new third generation feathers and some old second generation scapulars; the new scapulars appear very dark blackish grey with black shaft streaks. The old second generation scapulars have an obvious pattern of anchors and an accentuated shaft-streak.
The wing-covert panel has been replaced almost completely on the wintering ground, except the outer greater coverts and the upper row of the lesser coverts. The tertials, central greater coverts, most of the median coverts and lower lesser coverts are second generation feathers now, most with a similar pattern as the old second generation scapulars. The second generation central greater coverts show a vermiculated pattern. After arrival in Scandinavia, this bird started another moult wave in the coverts: the upper tertial is missing, two inner greater coverts are replaced, one inner median covert and some central lower lesser coverts are replaced as well, all very much fuscus-like in being dark grey. Old bleached second generation coverts strongly contrast with the new feathers. The bare parts are still immature: the bill is dark, the legs are pink and the iris is dark.

Moult score overlaps with average intermedius/graellsii in July in NW Europe (see July section), but see e.g. this advanced LBBG in the Netherlands, with P6 fully grown and P7 growing.

Typical Finnish fuscus in July have replaced primaries, rectrices and secondaries, all moulted in a complete post-juvenile moult on the wintering grounds, prior to northbound migration. The new second generation primaries are only a couple of months old and still look dark blackish. The second generation tail-feathers normally still show the white tips, but in some individuals these tips are worn away when 2cy birds arrive back in Scandinavia. Immediately after returning in Scandinavia some 2cy fuscus start a new moult cycle in the inner primaries, now growing in third generation feathers. 
The complete moult in the winter quarters normally start with replacement of the scapulars and mantle-feathers in November to January, but the post-juvenile moult may already start in juvenile birds which are still in Scandinavia in September. The new scapulars often show a simple pattern of a black shaft-streak on a dark brown base. When most of the scapulars are replaced, fuscus start to replace the wing-coverts, in the ordinary sequence that can also be found in other gull taxa in Europe. Wing-covert moult is initiated in two loci, one wave starts in the outermost coverts, one wave starts in the innermost coverts. The two waves normally meet at covert #7-8. Normally the median covert row is the first row which is moulted, followed by the lower lesser coverts, the greater coverts and moult finishes in the outer lesser coverts (the carpal edge). If for whatever reason, moult in the wing-coverts is arrested, this is normally most obvious in the carpal edge and outer greater coverts, containing juvenile feathers which contrast with the other fresh coverts. 
In classical 2cy fuscus, all wing-coverts are replaced to second generation on the wintering grounds, and by mid July in Scandinavia, a next moult wave is initiated, often including the median and lower lesser coverts, the inner greater coverts, upper tertials and scapulars. Bare part coloration may be very immature, including a black bill, but may also be very mature, with a yellow base and a red gonydeal spot on the lower mandible. Still, these birds are only 12 months old.