Herring Gull- Zilvermeeuw (argentatus & argenteus)

(last update: December 15, 2011 )

Herring Gull - 2cy January

Introduction

This website deals with the Herring Gulls of the taxa argentatus and argenteus. Argenteus is an abundant breeding species on Iceland, Britain, NW France, Belgium, the Netherlands and N Germany. The taxon argentatus breeds in NE Europe, from Denmark, the coast of the Baltic Sea, Scandinavia and coast of the White Sea. In the centre of the breeding range (Denmark and the NW German coast), birds show intermediate characteristics, indicating there is a cline in argenteus-argentatus. Argenteus in Western Europe is pale-backed, slightly smaller and with relatively much black in the wing-tip; argentatus in the NE Europe is larger, slightly darker on upper-parts and show less black in the wing-tip.
Due to the large breeding range, there is much intra-specific variation in argentatus, with most large, powerful birds in the northern populations, showing the most darkest upper-parts, longest wing and most white in the outer-wing. In this region, some populations may hold substantial number of yellow-legged argentatus. (referred to as "Finnmark yellow-legged argentatus"). In adult plumage, the black sub-terminal spot on P5 is often lacking or strongly reduced to a diffuse streak, broken at the centre. Sometimes P6 lacks black as well. 
In the Baltic region, other yellow-legged argentatus populations occur ("Baltic yellow-legged argentatus"), with adults showing even brighter yellow legs in summer and the upper-parts only slightly darker than West European argenteus, still much paler than Yellow-legged Gull (michahellis). Those Baltic argentatus often show a black sub-terminal spot on P5 in adult plumage.
On these web-pages, we largely follow P.J. Grant: "Gulls, a guide to identification" and E.K Barth's publication as Contribution No. 86, Zoological Museum, University of Oslo: "The circumpolar systematics of Larus argentatus and Larus fuscus with special reference to the Norwegian populations".


Common sight at the Dutch beach after storm: foraging argentatus and argenteus Herring Gulls at Scheveningen beach January 24 2003.

2cy Herring Gull: description for January

By January, NW European Herring Gull are in 'first winter' plumage, with most of the scapulars second generation, while birds hatched in northern Russia may still show a complete juvenile plumage, with the head and under-parts streaked grey-brown, rather pale on forehead and throat and with dark ear-coverts. The mantle and scapulars in these juveniles are brown based with buffish-yellowish fringes when the feathers are fresh. The notched pattern is repeated on the lesser, lower lesser and median coverts, although the medians often have paler centres. The greater coverts show a 'piano-key' pattern. On average, the tertials have an obvious notched pale fringe and transversal bar. This is more pronounced in argenteus than in argentatus. The secondaries, primaries and primary coverts are dark with a small white tip (which are often worn away in January), but the inner primaries show an obvious, sometimes translucent, pale window, prominent from below and above. The under-wing is rather uniform grey-brown patterned. The tail has a broad sub-terminal band and isolated dark bars on the basal half. Some argentatus show a broken tail-band, reminiscent to Great Black-backed Gull (L. marinus). The iris is very dark, the bill is blackish, sometimes with a paler base in January, and the legs are flesh-pink with dark shins.

2cy Herring Gull: post-juvenile moult

The partial autumn moult (moult into so-called "first winter" plumage) includes the body and head feathers. This moult starts as soon as the nest is abandoned (especially in southern populations) and continues until January. Early argenteus juveniles fledge by late-June in the Netherlands, argentatus fledge mid-July in northern USSR. The post-juvenile moult is most extensive in southern Herring Gull populations. Northern juvenile argentatus may postponed the post-juvenile moult until February, hence retain a complete juvenile plumage (e.g. this Russian 2cy argentatus in February).
In the post-juvenile moult, the head turns paler on throat and forehead. The breast turns paler as well, but most is an effect of bleaching and wear.
1cy January birds in NW Europe have the mantle and scapulars moulted to second generation feathers, showing an anchor pattern and a dark base. This moult normally starts in the rear upper scapular region high on the back, and progresses downwards to the lower scapulars. The rear lower scapulars, which are the longest scapulars, lying on the scapular coverts, are normally still juvenile by February (see charts below for argentatus in Poland). 
By January, about half of the argentatus in Poland have all upper scapulars replaced and almost 90% have >75% second generation upper scapular (i.e. category A-B in our research). When the feathers are fresh, they may show warm ginger tones, but after a few weeks these warm tones bleach paler, to white later in the season. 
In 2cy argenteus in NW France (from Belgian, Dutch and British populations), the lowest row of scapulars are still juvenile by 2cy March in the vast majority of birds (contra e.g. the southern taxon michahellis). 

Both argenteus and argentatus normally exclude all tertials and wing-coverts from the post-juvenile moult. However, we estimate 2-4% of argenteus to include one or a few wing-coverts or a single tertial in the post-juvenile moult (often in a later stage of this moult, when scapular moult is well underway). We don't have sufficient data to estimate for argentatus, but several pictures show this phenomenon in argentatus as well. The juvenile wing-coverts, rectrices and remiges start to bleach and show wear in the fringes from 1cy September onwards.

Moult surveys: some notes

From a "definition point of view", we score birds category F (0% 2g feathers) as the second generation feathers are still not visible. Only when these new feathers are visible, birds move to category E (1-24% 2g), as it is very hard to interpret missing minute upper scapulars in the upper region. On the other far end we have category A (100% 2g feathers) which is only used when the longest rear lower scapulars are dropped as well. By this stage, we don't see any juvenile scapulars, presuming they are now all 2g feathers. These longest scapulars are the last to be moulted in the entire scapular region. Some birds already moult to third generation scapulars in the upper region, while these longest lower scapulars are still juvenile.

2cy Herring Gull January: tables and charts

Jan-Chart 1 (below): 2cy argentatus HG coverts & scapulars scores 13-01-2004, at Lubna, Poland (n = 37). 
TT & COVS: moult score in tertials and wing-coverts.
2g US: second generation upper scapulars; LS: lower scapulars.
TOTAL SCAPS: % of second generation scapulars.
Classification: A: 100% 2g; B: 75-99% 2g; C: 50-74% 2g; D: 25-49% 2g; E: 1-24% 2g; F: 0% 2g.

Jan-Chart 2 (below): 2cy argentatus HG coverts & scapulars scores 15-01-2004, at Lubna, Poland (n = 9). For classification and codes, see table above.

Jan-Chart 3 (below): 2cy argentatus HG coverts & scapulars scores 16-01-2004, at Lubna, Poland (n = 36). For classification and codes, see table above.

rings argenteus: U.K.


2cy argenteus in March, ringed in France. (57822 bytes)Herring Gull WH5T., 2cy (argenteus), January 31 2010, Boulogne/Mer, France (50.42N,1.34E). Picture: J-M Sauvage.
1cy argenteus in November, ringed in Belgium. (25637 bytes)Herring Gull A3MM 2cy (argenteus), January 2007, Oostende, Belgium. Picture W. Leers.
rings argenteus: France
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rings argenteus: Belgium
1cy argenteus in November, ringed in Belgium. (25637 bytes)Herring Gull FBAD 2cy (argenteus), January 2007, Oostende, Belgium.
1cy argenteus in November, ringed in Belgium. (25637 bytes)Herring Gull MJAG 2cy (argenteus), January 19 2010 Scheveningen, the Netherlands. 
2cy argenteus in March, ringed in France. (57822 bytes)Herring Gull (argenteus) 2CY YUAC January - February 2013, Calais, NW France. Picture: Jean-Michel Sauvage.
2cy argenteus in January, ringed in Belgium. (80891 bytes)Herring Gull H-117748 2cy (argenteus), January 04 2002, Boulogne/Mer, France (50.42N,1.34E).
2cy argenteus in January, ringed in Belgium. (76494 bytes)Herring Gull H-117045 2cy (argenteus), January 04 2002, Boulogne/Mer, France (50.42N,1.34E).
2cy argenteus in January, ringed in Belgium. (92295 bytes)Herring Gull H-117774 2cy (argenteus), January 04 2002, Boulogne/Mer, France (50.42N,1.34E).  
1cy argenteus in November, ringed in Belgium. (94977 bytes)Herring Gull 429 2cy (argenteus), January 2007, Oostende, Belgium. Pictures W. Leers.
rings argenteus: the Netherlands
1cy argenteus in September (65624 bytes)Herring Gull (argenteus) LP September 17 2013 & January 30 2014, Katwijk, the Netherlands.
1cy argenteus in December, ringed in the Netherlands. (119951 bytes)Herring 5.429.2872cy (argenteus), 2010-2011, IJmuiden, the Netherlands.
2cy argenteus in January, ringed in Belgium. (92295 bytes)Herring Gull NLA 5.420.564 2cy (argenteus), January 08 2009, IJmuiden, the Netherlands.  
argenteus in January, ringed in the Netherlands. (61284 bytes)Herring Gull 5.352.764 2cy (argenteus), January 19 2003, IJmuiden, the Netherlands (52.27N-04.33E). Seen in eight years.
rings argentatus: Helgoland / Germany
argentatus in January, ringed in Denmark. (56599 bytes)Herring Gull 2cy H16L (argentatus) January 24 2012, Katwijk, the Netherlands.
argentatus in January, ringed in Denmark. (56599 bytes)Herring Gull 2cy H6N4 (argentatus) January 02 2012, Katwijk, the Netherlands.
argentatus in January, ringed in Denmark. (56599 bytes)Herring Gull DEW 4304457 2cy (argentatus), November 2009 & January 2010, IJmuiden, the Netherlands.
argentatus in January, ringed in Helgoland.Herring Gull xxx4248 2cy (argentatus), January 29 2006, IJmuiden, the Netherlands. Picture Robert Heemskerk.
rings argentatus: Denmark
argentatus in January, ringed in Denmark. (56599 bytes)Herring Gull DKC 3076442 2cy (argentatus), January 24 2003, Scheveningen, the Netherlands. 
rings argentatus: Estonia
argentatus in January, ringed in Estonia. (65488 bytes)Herring Gull T 95.398 2cy (argentatus), January 13 2004, Lubna rubbish dump, Poland (52°02'N 21°08'E).
argentatus in January, ringed in Estonia. (61532 bytes)Herring Gull T 93.788 2cy (argentatus), January 15 2004, Lubna rubbish dump, Poland (52°02'N 21°08'E).
rings argentatus: Norway
Herring Gull 2cy (argentatus) J59R January 29 2005, S Norway. Picture Nils Helge Lorenzen.
Herring Gull 2cy (argentatus) JN5M January 26 2005, S Norway. Picture Nils Helge Lorenzen.
rings argentatus: Russia
2cy argentatus in Jan-Febr, ringed in Russia.Herring Gull KH89 2cy (argentatus), January 29 2010, IJmuiden, the Netherlands.
2cy argentatus in Jan-Febr, ringed in Russia.Herring Gull KV79 2cy (argentatus), January - February 2007, Westkapelle, the Netherlands. Pictures Pim Wolf.
unringed 2cy Herring Gulls
3cy argentatus in January. (80207 bytes)Herring Gull 2cy, January 23 2013, Katwijk, the Netherlands.
3cy argentatus in January. (80207 bytes)Herring Gull 2cy, January 23 2013, Katwijk, the Netherlands.
3cy argentatus in January. (80207 bytes)Herring Gull 2cy, January 23 2013, Katwijk, the Netherlands.
3cy argentatus in January. (80207 bytes)Herring Gull 2cy, January 23 2013, Katwijk, the Netherlands.
3cy argentatus in January. (80207 bytes)Herring Gull 2cy, January 23 2013, Katwijk, the Netherlands.
3cy argentatus in January. (80207 bytes)Herring Gull 2cy, January 23 2013, Katwijk, the Netherlands.
3cy argentatus in January. (80207 bytes)Herring Gull 2cy, January 23 2013, Katwijk, the Netherlands.
3cy argentatus in January. (80207 bytes)Herring Gull 2cy, January 06 2012, Katwijk, the Netherlands.
2cy argentatus in Jan-Febr, ringed in Russia.Herring Gull 2cy (argentatus), February 04 2007, Westkapelle, the Netherlands. Picture Pim Wolf.
2cy argentatus in January. (74084 bytes)Herring Gull 2cy (argentatus), January 29 2006, IJmuiden, the Netherlands. Picture: Robert Heemskerk.
2cy argentatus in January. (88439 bytes)Herring Gull 2cy (argentatus), January 04 2002, Boulogne/Mer, France (50.42N,1.34E).
2cy argentatus in January. (74084 bytes)Herring Gull 2cy (argentatus), January 04 2002, Boulogne/Mer, France (50.42N,1.34E).
2cy argenteus in January. (93724 bytes)Herring Gull 2cy (argenteus), January 04 2002, Boulogne/Mer, France (50.42N,1.34E).