Yellow-legged Gull - Geelpootmeeuw (L. michahellis): 3cy August
(last update: 10 december 2003)
(2 images) Yellow-legged Gull michahellis 3cy, August 09 2003, Etaples, France (50.42N, 1.34E).
In 3cy birds, the old second generation flight-feathers are replaced by new, more adult-like third generation feathers. This is most obvious in the (outer) primaries. The old second generation P10 is brown, abraded and will be replaced by glossy-black fresh third generation P10 showing an obvious mirror.
The primary moult
stage in the central bird (top image): P9-10 are old
second generation and P6 is full-grown. P7 is at the length of P5. The
complete moult in the secondaries has started as well and is normally
initiated at the division between primaries and secondaries (S1, next to
P1). The primaries are dropped in an almost constant interval, but moult
in the secondaries may evolve much quicker: the first outermost
secondaries (S1 to S3) are normally shed one by one with reasonable
intervals, but the inner secondaries are almost dropped simultaneously,
leaving large gaps in the inner-arm by the end of August.
Bottom picture: almost same moult stage. Note faint black on outer-web of P4, common in 3cy michahellis, but not commonly shown in older plumages.