Primary P4 and P5 pattern variation in Dutch Herring Gull YDBM over multiple seasons

Just for reference: images of the variation in the pattern of primary P4 and P5 of female Dutch Herring Gull Green YDBM, which we ringed as an adult in 2020 in the IJmuiden Forteiland colony, the Netherlands. The changes over the years are small, but interesting: When following discussions within the gull community, I sense …

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