Yellow-legged
Gull - Larus michahellis
(last update: October 08 2013)
Coordinators:
Delfín González
Gabriel Martín
Antonio Gutierrez
Amir Ben Dov
Mars Muusse
Yellow-legged Gull michahellis 2CY, August 25 2000, Etaples / Boulogne-sur-Mer, NW France.
Primary
moult score: P8 is fully grown, P9 has to grown a few inches and P10 is
halfway it's final length. Another example showing the secondary moult
stage. By July, most of the secondaries have been shed (click the thumbnail for the secondary moult stage of July michahellis) but in the
majority of the birds, a small block of juvenile secondaries remain at the
inner half of the arm. Secondaries are moulted in descendant order, S1 is
the first moulted feather (the outermost secondary) and in a wave, new
secondaries grown inwards. The two or three innermost secondaries, often
hidden by the tertials, are moulted simultaneously and finally the small
block of juvenile secondaries is shed as well. Now, by the end of August,
it's this group of secondaries which are renewed last in line and as can
be seen in the left picture, the gap is closed from two directions.
The complete tail has been replaced. Note the gap in the central median
coverts and the outermost greater coverts which is still growing. All
second generation secondaries show a neat dark centre and a white zigzag
pattern created by the neat white fringes. Note the grey scapulars and the
predominantly white upper-tail coverts, contrasting with the broad
tail-band. The second generation inner primaries show a window, which is
more obvious in 2CY than it is in 1CY, but still not as well-defined as in argenteus Herring Gull.