In 2010 I was asked by marine ornithologist Kees Camphuysen to co-write an article about a European Herring Gull Larus argentatus argenteus ringed in 1986 as a juvenile in the dunes of Wassenaar, near The Hague (Netherlands).
The basis for this article were some 30+ observations that I had acquired of this bird since first discovering it in my home town of Leiden in June 2009.
The project for which the bird was ringed is managed by Kees Camphuysen and as such I sent him all my observations of that bird. Kees is also the Editor of SULA, the magazine of the Dutch Seabird Group, in which the article appeared.
The majority of observations were done on late afternoons on Saturdays, when the local fish market came to a close, thereby presenting opportunities for the local gulls to feed on scraps of fish.
During these observations, I meticulously recorded the moult pattern in the wings and kept track of other noticeable changes such as the appearance on the right side of the head of a bare patch during the moult to non-breeding plumage, as well as damage done to the color rings.
The article titled “MOULT AND SITE-FIDELITY OF HERRING GULL „ZDGA‟ BASED ON COLOUR-RING SIGHTINGS” appeared in SULA volume 23(2), 2010, pages 69-86, and can be downloaded here (with kind permission from Kees). It is in Dutch but does contain photo captions and a summary in English.
I’m happy to say that at the time of writing, ZDGA is still very much alive at the age of 27 years and regularly observed and documented.