Herring Gull- Zilvermeeuw (argentatus & argenteus)

(last update: 22-12-2006)


Herring Gull plumages:

hg 1cy July
hg 1cy August
hg 1cy September
hg 1cy October
hg 1cy November
hg 1cy December

hg 2cy January
hg 2cy February
hg 2cy March
hg 2cy April
hg 2cy May
hg 2cy June
hg 2cy July
hg 2cy August
hg 2cy September
hg 2cy October
hg 2cy November
hg 2cy December

hg 3cy January
hg 3cy February
hg 3cy March
hg 3cy April
hg 3cy May
hg 3cy June
hg 3cy July
hg 3cy August
hg 3cy September
hg 3cy October
hg 3cy November
hg 3cy December

hg sub-ad January
hg sub-ad February
hg sub-ad March
hg sub-ad April
hg sub-ad May
hg sub-ad June
hg sub-ad July
hg sub-ad August
hg sub-ad September
hg sub-ad October
hg sub-ad November
hg sub-ad December

hg ad January
hg ad February
hg ad March
hg ad April
hg ad May
hg ad June
hg ad July
hg ad August
hg ad September
hg ad October
hg ad November
hg ad December

(4 images) Herring Gull DA 2163212cy (argenteus), May 17 2002, Boulogne/Mer, France (50.43N-01.37E).

A 2cy argenteus with a French ring: Museum Paris DA 216321. This is a local argenteus, ringed in the Pas-de-Calais region, near the village of Wimereux, NW France (50.46N,01.36E), only 6.6 kilometers from the place it spend the entire summer in 2cy. It was ringed as 1cy bird on July 23 2001, but ring-data do not tell whether it was born at that location or not. 
This bird was seen in April, June and July, and the images nicely illustrate that f
rom late April onwards, argenteus has a complete moult during summer to so-called "second winter" plumage. This complete moult will be finished by October. The head appears white from May to July and will be moulted by July-August and will show neat fine streaking by October. The under-parts and rump turns pale, mottled with brown. From mid-April, the scapulars and mantle are replaced by third generation feathers, starting with the replacement of the lower upper scapulars. This bird has five lower upper scapulars replaced. The pattern of the third generation scapulars is more or less similar to the anchor pattern of the second generation feathers, but they can be recognized by the warm buffish tone and neat white fringe as long as the feathers are fresh. In argenteus, some new scapulars may appear adult-like pale grey, but most new feathers will show an anchor pattern and this still applies on the new feathers in September.

From early April, the inner primaries are shed and new second generation primaries grown in. The last juvenile primary (P10) will be shed by the first week of August. The majority of argenteus complete the primary moult by the first week of October, with a new second generation P10 fully grown. The new primaries are dark with a tiny pale tip on the fresh flight-feathers. Again, the four inner primaries show an extensive pale window, as both inner and outer-web are pale greyish white-brown, contrasting with the outer-wing. A pale inner-web can still be found in P7. This bird has advanced primary moult compared to Belgian and Dutch argenteus (which show P1 to P3 missing); this French argenteus has P1-P3 fully grown and the outer primaries P6-P10 still juvenile. Remarkably, three Paris-ringed Herring Gulls were found with the same moult score. Compared with a sample of 75 randomly chosen 2cy Herring Gulls, only two other birds had dropped p5. Thus, as first figures indicate, Herring Gulls from French colonies may be ahead in primary moult about one full primary. 
The complete tail is still juvenile in this individual.
The second generation tail-feathers will show a clear-cut blackish tail-band with only isolated blackish markings on the white basal half. 
Wing-covert moult has started as well:
the greater coverts #1-3 are new second generation coverts; all other greater coverts are still juvenile. In the median coverts, #1 is second generation, #2-3 are missing, #4 is growing, #5 is growing but shorter than #4 and #6-14 are new feathers. In the lower lesser coverts, #1-2 are new, #3 is juvenile, #4 is missing, #5-8 are juvenile, #9-10 are missing, #11 is juvenile, #12 is missing and #13 and further outwards is still juvenile. All lesser coverts are still juvenile but a single outer lesser covert has been dropped. Tertial #1-2 have been replaced, with the other tertials still juvenile.
From late April, argenteus will replace the wing-coverts and tertials, starting with the median coverts, upper tertials and innermost greater coverts. The fresh feathers will be buffish-based with an obvious barred pattern. By July, the warm tones of the first moulted feathers are faded to plain white, leaving a contrasting barred pattern on the wing-coverts. The last coverts to be moulted are the central greater coverts, replaced by mid-August. The new greater coverts may show a vermiculated, densely barred pattern.

Unlike the 2cy individual ringed DA 216323, this bird DA 216321 has the greater coverts very bleached. These Paris-ringed argenteus are different from Dutch/Belgium Herring Gulls in some respects: 
- First, they are diagnosable ahead in general moult compared to Herring Gulls from IJmuiden and Scheveningen (the Netherlands in general). 
- Second, the have a different stance, jizz, in some birds combined with a narrow tail-band, relatively dark inner-hand and stout pale pink legs, reminding Yellow-legged Gull characteristics. 

image above: DA 2163212cy, May 17 2002, Boulogne/Mer, France (50.43N-01.37E).

image below: DA 2163212cy, June 13 2002, Boulogne/Mer, France (50.43N-01.37E).

In June, DA 216321 strongly resembles another Paris-ringed argenteus present on Boulogne-sur-Mer and ringed: DA 216323 Museum Paris.
In many respects DA 216321 is similar to average argenteus Herring Gull from Belgium and the Netherlands, although the barred pattern in the tertials and inner greater coverts is very bold and dark, as can be found commonly in michahellis. Note the freshly moulted greater and median coverts, with broad brown bars and buffish based centres on the recently moulted feathers. The juvenile secondaries, which are well visible now all the central greater coverts have been shed, have paler brown centres, slightly bleached. The outer greater coverts are growing inwards (in descending order, outer feathers moulted first) and are just visible behind the flank feathers. The outer primaries are very bleached, washed brown and very abraded at the tips. The primary moult in Paris-ringed argenteus is noticeably advanced. The image below shows DA 216321: P7 missing and P8 still juvenile. Two small surveys of primary moult score in Le Portel are presented below:

Primary moult score in 2cy argenteus at Le Portel - Boulogne/Mer, June 13 2002.
p4 missing 2 5 7%
p5 missing 2 21 24%
p6 missing 13 43 58%
p7 missing 4 (incl Paris ring) 6 10%
  n = 21; m = 5.9; sd = 0.83 n = 75; m = 5.7; sd = 0.72  

images below: DA 2163212cy, July 10 2002, Boulogne/Mer, France (50.43N-01.37E).

2cy DA 216321 was still present in July 2002. Again, this French-ringed argenteus belongs to the most advanced argenteus present at Boulogne-sur-Mer, regarding moult-stage. P7 is already longer than P6 and only P10 is still juvenile. As can be seen in the table below, such advanced primary moult occurs in less than 3% of 2cy Herring Gulls at Le Portel (n = 146, origin of this mixed flock unclear, but probably belonging to colonies in NW France, Belgium and the Netherlands, Britain not certain).
In the rectrices, R1-2 are fresh second generation, R3 is growing, R4-6 are still old juvenile. Remarkably, the new tail-feathers lack the obvious white fringe, but the dark, blackish centre strongly contrasts with the bleached brown centres of the juvenile tail-feathers. 
The tertials are now all fresh second generation and the upper tertial, moulted first in line shows some wear in the tip already. Greater coverts #1-3 are second generation, moulted earlier and with slight wear in the tips already. The greater coverts from #4 outwards are all very fresh. Median coverts #1-6 are similar to the inner greater coverts, #7 is very fresh and from #8 outwards the medians show slight wear again. In the lower lesser coverts, #1-2 are fresh, #3 is still juvenile, #4 is second generation with wear, #5 is growing and from #6 outwards the lower lesser covert row is complete. About 75% of the lesser coverts has been replaced for fresh second generation coverts and one feather is an older second generation feather, showing wear already.
A small surveys of primary moult score and a survey on secondary/rectrices moult in Le Portel are presented below:

Primary moult score in 2cy argenteus at Le Portel - Boulogne/Mer, July 10 2002. (n = 146; m = 7.4; s = 0.66)
p6 missing 10 (7%)
p7 missing 66 (45%)
p8 missing 66 (45%)
p9 missing 4 (3%)
Secondary and rectrices moult score in 2cy argenteus at Le Portel - Boulogne/Mer, July 11 2002. (n = 40)
secondaries or rectrices not moulting 10
only rectrices moulting 8
only secondary moulting -
secondaries and rectrices both moulting 22