Another rare example of a European Herring Gull with a tertial spot.
It was ringed as an adult female in the breeding colony of Europoort, near Rotterdam, the Netherlands in May 2015 and seen aged older than 5th calendar year in November 2016 at Katwijk aan Zee, the Netherlands:
It was not reported if this individual also showed this tertial spot in 2015, so it is assumed that it was not present.
Sightings of tertial spots in Herring Gulls are rare. For more examples, including in other species, see
Tertial spots in sub-adult and adult gulls.