Primary moult variation in adult Black-headed Gulls – 20140628

Images of adult Black-headed Gulls Chroicocephalus ridibundus showing a large variation in primary moult, ranging from all primaries still present to having dropped primary P5.

All images were taken in the breeding colony near Zoetermeer, the Netherlands, 28 June 2014.

No primary moult

Individual #1, White E5FL

Age: older than 7 calendar years
Sex: male
W[E5FL]-20140628

P1 growing, P2 dropped, P3 to P10 present

Individual #2, White E5CN

Age: older than 8 calendar years
Sex: male

W[E5CN]-20140628-1

Individual #3, White E5JY

Age: 5th calendar year
Sex: female

W[E5JY]-20140628

Individual #4, White E5UT

Age: 4th calendar year
Sex: male
Note that P2 is present in the left wing but has been dropped in the right wing.

W[E5UT]-20140628

W[E5UT]-20140628-2

Individual #5, White E5ZR

Age: 3rd calendar year
Sex: unknown
Note the black mark on the alula.

W[E5ZR]-20140628

P1 to P3 dropped/growing, P4 to P10 present

Individual #6, White E5VR

Age: older than 4 calendar years
Sex: male

W[E5VR]-20140628

P1 & P2 growing, P3 to P4 dropped/growing, P5 to P10 present

Individual #7, White E5RE

Age: older than 6 calendar years
Sex: female

W[E5RE]-20140628

P1 & P2 fully grown, P3 & P4 growing, P5 dropped, P6 to P10 present

Individual #8, White E5PE

Age: 5th calendar year
Sex: male

W[E5PE]-20140628

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