Black-headed Gull Chroicocephalus ridibundus

(last update: 3-04-2011)

Below: First-calendar year Black-headed Gull E5LU, July 1, 2010, Benthuizerplas, Zoetermeer, The Netherlands (52.07N 04.53E). Photo: Maarten van Kleinwee.

First-calendar year Black-headed Gull, moulting to first-winter (formative) plumage. In this post-juvenile moult, all feathers are replaced except those on the wings and in the tail.

In this individual, the body is now almost completely white and the brown markings on the head and hind neck have started to fade. The scapulars and mantle feathers still show predominantly first-generation, juvenile brown feathers.

This individual was ringed as part of the Dutch RAS project (Recapturing Adults for Survival; research on survival of Dutch breeding birds).
For more information about the RAS project, visit http://frankmajoor.nl/kokmeeuwen-broedvogels1-uk.shtml.