Gulls in NW Europe

(last update: September 25, 2011 )

Herring Gull 6cy 5.419.235 (argenteus) July 2010 - November 2011, Leiden, the Netherlands. Pictures: Maarten van Kleinwee.

Ringed as 2cy on August 11, 2007 at IJmuiden, The Netherlands.

Herring Gull 6cy 5.419.235 (argenteus) November 18 2011, Leiden, the Netherlands.

Adult Herring Gull moulting to winter (basic) plumage: P9 is fully grown, P10 is almost fully grown. A small black mark can be seen on the lower mandible.

below: 6cy 5.419.235 (argenteus) August 27 2011, Leiden, the Netherlands.

Adult Herring Gull moulting to winter (basic) plumage: P7 has been dropped. P5 / P8.

below: 5cy 5.419.235 (argenteus) July 17 2010, Leiden, the Netherlands.

Fifth-calendar year Herring Gull moulting to winter plumage. P1-3 are new and fully grown, P4 is missing. In the right wing, P9 is also missing but this is not part of the moult process. Moult score: 16 (P1=5, P2=5, P3=5, P4=1, P5=0, P6=0, P7=0, P8=0, P9=0, P10=0)

below: 5cy 5.419.235 (argenteus) June 12 2010, Leiden, the Netherlands.

below: 5cy 5.419.235 (argenteus) June 12 2010, Leiden, the Netherlands.

below: 5cy 5.419.235 (argenteus) May 22 2010, Leiden, the Netherlands.

Fifth-calendar year Herring Gull in summer plumage.

below: 5cy 5.419.235 (argenteus) May 08 2010, Leiden, the Netherlands.

below: 5cy 5.419.235 (argenteus) April 16 2010, Leiden, the Netherlands.

Summer plumage; spreading wings in an attempt to ward off a nearby gull from the food it has found.

Below: A common sight on those days when the garbage is collected: gulls picking open the garbage bags.

below: 5cy 5.419.235 (argenteus) April 10 2010, Leiden, the Netherlands.

Summer plumage.

below: 5cy 5.419.235 (argenteus) March 27 2010, Leiden, the Netherlands.

At the end of its fourth calendar year, Herring Gulls obtain the adult plumage, making it impossible to age them. The eye ring on this individual is yellow-orange. The primary pattern shows a large mirrow on P10, a small mirror on the inner web of P9 and a small black mark on the outer web of P5.

below: 4cy 5.419.235 (argenteus) September 26 2009, Leiden, the Netherlands.

Fourth-calendar year Herring Gull moulting to fourth-winter plumage. Due to the fact that P9 en P10 have been dropped and that P8 is not fully grown yet, no dark primaries are extending beyond the tertials, giving this gull an unbalanced appearance. The moult has now also reached the neck and head, showing the striped winter pattern. Note the light iris and the dark markings on the bill.

below: 4cy 5.419.235 (argenteus) September 05 2009, Leiden, the Netherlands.

Moulting to fourth-winter plumage. At the beginning of September, the iris is starting to get lighter and the bill is faintly showing the black markings of the oncoming winter plumage. P10 is still third-generation.

below: 4cy 5.419.235 (argenteus) August 01 2009, Leiden, the Netherlands.

Fourth-calendar year Herring Gull moulting to fourth-winter plumage. The third-generation coverts are looking very light due to extensive wear. De outer primaries P7-10 are still third-generation.

below: 4cy 5.419.235 (argenteus) July 29 2009, Leiden, the Netherlands.

P1-3 are new and fully grown, P4 is new and growing, P5 is missing and P6-10 are third-generation. Note the dark iris and the adult-looking bill and tail. Moult score: 18 (P1=5, P2=5, P3=5, P4=2, P5=1, P6=0, P7=0, P8=0, P9=0, P10=0). Third gen secondaries with (partly) dark centres.

below: 4cy 5.419.235 (argenteus) July 22 2009, Leiden, the Netherlands.

In July, some of the tertials are worn down to their shaft.

below: 4cy 5.419.235 (argenteus) June 27 2009, Leiden, the Netherlands.

P1 is new and fully grown, P2 is missing and that P3-10 are third-generation. The outer primaries wear the final black pattern, with P5 showing a small black mark on the outer web. The mirror on P10 is not fully developed yet, while P9 does not yet have its mirror. The tail is completely white. Moult score: 6 (P1=5, P2=1, P3=0, P4=0, P5=0, P6=0, P7=0, P8=0, P9=0, P10=0).
The old and worn third-generation tertials en coverts still show a brown pattern, and contrast with the moulted gray scapulars, median coverts and lesser coverts. The iris is still relatively dark, the eye ring is orange-yellow and the bill does not have any black markings.