Herring Gull- Zilvermeeuw (argentatus & argenteus)

(last update: December 15, 2011 )

Herring Gull - 1cy September

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".

1cy Herring Gull: description for September

By September, NW European Herring Gull is not in fresh juvenile plumage anymore. But birds hatched in northern Russia 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, 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, and the legs are flesh-pink with dark shins.

1cy 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 and very obvious in September. Northern juvenile argentatus may postponed the post-juvenile moult until February, hence retain a 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. The feathers on belly and vent remain juvenile in most 1cy argenteus by November. 
1cy September birds in NW Europe have the mantle and upper 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. By September, it is not uncommon to see birds with most of the upper scapulars replaced (over 50% second generation, i.e. category A-C 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.

Most 1cy argenteus and argentatus from S-Scandinavia show post-juvenile moult by September. We do not get high northern birds so early in autumn, but ringed bird in November - March show that these populations  may remain completely juvenile for a much longer period. Below, we included a table of 11 ringed argenteus and argentatus, of which only 2 did not start the post-juvenile moult. However, both birds had obvious moult gaps, with a few upper scapulars missing, so the post-juvenile moult must have been visible on the last day of September. In these birds, active moult is obvious by the large moult gaps, showing the bases of the underlying feathers. From a "definition point of view", we score this 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. 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.
By September, most advanced birds (like A1DC and A1FV) have almost all upper scapulars new and up to 25% of the lower scapulars replaced. 

1cy Herring Gull September: tables

CODE DATE SIDE RING TT & COVS 2g   TOTAL
        # US LS SCAPS
BLB 22-sep R H-124344 0 E F E
BLB 22-sep R H-124484 0 C F D
BLB 12-sep R H-131797 0 C E D
BTO 22-sep R A1DC 0 B E D
BTO 22-sep R A1FV 0 B E D
BTO 22-sep L A1HB 0 D E E
NLA 26-sep nn 5.412.502 0 E F E
NLA 26-sep R 5.412.154 0 E E E
NLA 24-sep R 5.413.032 0 E F E
NLA 18-sep L 5.413.050 0 F F F
NLA 18-sep L 5.413.051 0 F F F

post-juvenile moult score of several ringed L. argentatus argenteus in 2002 and 2003. 
Code BLB: ringed in Belgium; BTO: ringed in the UK; NLA: ringed in the Netherlands.
Side L: left; R: right; nn: not noted.
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.

rings argenteus: U.K.

1cy argenteus in September, ringed in the UK. (71936 bytes)Herring Gull A1FV 1cy (argenteus), September 22 2002, Boulogne/Mer, NW France (50.43N-01.37E).
1cy argenteus in September, ringed in the UK. (69121 bytes)Herring Gull A1HB 1cy (argenteus), September 22 2002, Boulogne/Mer, NW France (50.43N-01.37E).
1cy argenteus in September, ringed in the UK. (66151 bytes)Herring Gull A1DC 1cy (argenteus), September 22 2002, Etaples, NW France (50.43N-01.37E).
rings argenteus: France
2cy argenteus in March, ringed in France. (57822 bytes)Herring Gull M3A 1cy (argenteus), September 25 2007, Boulogne/Mer, France (50.42N,1.34E). Picture: J-M Sauvage.
2cy argenteus in March, ringed in France. (57822 bytes)Herring Gull WSA 1cy (argenteus), September 03 2009, Westkapelle, the Netherlands.
rings argenteus: Belgium
1cy argenteus in November, ringed in Belgium. (25637 bytes)Herring Gull CVAX 1cy (argenteus), September 21 2009, Westkapelle, the Netherlands.
1cy argenteus in November, ringed in Belgium. (25637 bytes)Herring Gull FLAH 1cy (argenteus), September 25 2007, Boulogne/Mer, France (50.42N,1.34E). Picture: J-M Sauvage.
1cy argenteus in November, ringed in Belgium. (25637 bytes)Herring Gull MBAM 1cy (argenteus), September 30 2009, Westkapelle, the Netherlands.
1cy argenteus in November, ringed in Belgium. (25637 bytes)Herring Gull MJAX 1cy (argenteus), September 30 2009, Westkapelle, the Netherlands.
1cy argenteus in November, ringed in Belgium. (25637 bytes)Herring Gull MSAG 1cy (argenteus), September 20 2009, Westkapelle, the Netherlands.
1cy argenteus in November, ringed in Belgium. (25637 bytes)Herring Gull MUAB 1cy (argenteus), September 23 2010, Westkapelle, the Netherlands.
1cy argenteus in November, ringed in Belgium. (25637 bytes)Herring Gull MXAC 1cy (argenteus), September 20 2009, Westkapelle, the Netherlands.
1cy argenteus in November, ringed in Belgium. (25637 bytes)Herring Gull PCAP 1cy (argenteus), September 16 2010, Westkapelle, the Netherlands.
1cy argenteus in November, ringed in Belgium. (25637 bytes)Herring Gull PDAP 1cy (argenteus), September 16-20 2010, Westkapelle, the Netherlands.
1cy argenteus in November, ringed in Belgium. (25637 bytes)Herring Gull PDAW 1cy (argenteus), September 21 2010, Westkapelle, the Netherlands.
1cy argenteus in November, ringed in Belgium. (25637 bytes)Herring Gull PJAD 1cy (argenteus), September 21 2010, Westkapelle, the Netherlands.
1cy argenteus in November, ringed in Belgium. (25637 bytes)Herring Gull PHAJ 1cy (argenteus), September 16 2010, Westkapelle, the Netherlands.
1cy argenteus in November, ringed in Belgium. (25637 bytes)Herring Gull SWAH 1cy (argenteus), September 23 2011, Westkapelle, the Netherlands.
1cy argenteus in September, ringed in Belgium. (63947 bytes)Herring Gull L-910995 1cy (argenteus), September 10 2009, Westkapelle, the Netherlands.
1cy argenteus in September, ringed in Belgium. (63947 bytes)Herring Gull L-910999 1cy (argenteus), September 10 2009, Westkapelle, the Netherlands.
juvenile LBBG in October, ringed in Norway. (131273 bytes)Herring Gull H-901568 1cy (argenteus), September 06 2010, Westkapelle, the Netherlands.
adult argenteus in October, ringed in Belgium. (60142 bytes)Herring Gull H-901610 1cy (argenteus), September 24 2010, Westkapelle, the Netherlands.
1cy argenteus in September, ringed in Belgium. (63947 bytes)Herring Gull H - 161180 1cy (argenteus), September 30 2009, Westkapelle, the Netherlands. Picture Pim Wolf.
1cy argenteus in September, ringed in Belgium. (63947 bytes)Herring Gull H - 124344 1cy (argenteus), September 22 2002, Boulogne/Mer, NW France (50.43N 01.37E).
1cy argenteus in September, ringed in Belgium. (72890 bytes)Herring Gull H - 124484 1cy (argenteus), September 22 2002, Boulogne/Mer, NW France (50.43N 01.37E).
1cy argenteus in September, ringed in Belgium. (76327 bytes)Herring Gull H - 131797 1cy (argenteus), September 12 2004, Westkapelle, the Netherlands (51.33N 03.25E). Picture Pim Wolf.
rings argenteus: the Netherlands
1cy argenteus in August, ringed in Belgium. (90559 bytes)Herring Gull Y.AFK 1cy (argenteus), September 09 2008, Katwijk, the Netherlands.
1cy argenteus in August, ringed in Belgium. (90559 bytes)Herring Gull Y.AMR 1cy (argenteus), September 12 2010, IJmuiden, the Netherlands.
1cy argenteus in September (65624 bytes)Herring Gull (argenteus) 1-2cy LP September 17 2013 & January 30 2014, Katwijk, the Netherlands.
1cy argenteus in September (65624 bytes)Herring Gull (argenteus) 1cy LS September 17 2013, Katwijk, the Netherlands.
1cy argenteus in September (65624 bytes)Herring Gull (argenteus) 1cy SR September 17 2013, Katwijk, the Netherlands.
1cy argenteus in September (65624 bytes)Herring Gull (argenteus) 1cy XD September 19 2013, Katwijk, the Netherlands.
1cy argenteus in September (65624 bytes)Herring Gull (argenteus) 1cy L.T September 19 2013, Katwijk, the Netherlands.
1cy argenteus in September (65624 bytes)Herring Gull (argenteus) 1cy P.= September 08 2013, Katwijk, the Netherlands.
1cy argenteus in September (65624 bytes)Herring Gull (argenteus) 1cy R.0 September 23 2013, Katwijk, the Netherlands.
1cy argenteus in November, ringed in Belgium. (25637 bytes)Herring Gull L.8 1cy (argenteus), September 03 2012, Katwijk, the Netherlands.
ad LBBG in winter, ringed in the Netherlands. (65647 bytes)Herring Gull (argenteus) 1cy ZA September 26 2012, Boulogne-sur-Mer, NW France. Picture: Jean-Michel Sauvage.
1cy argenteus in August, ringed in Belgium. (90559 bytes)Herring Gull CL 1cy (argenteus), September 23 2011, Westkapelle, the Netherlands.
1cy argenteus in August, ringed in Belgium. (90559 bytes)Herring Gull HH 1cy (argenteus), September 30 2009, Westkapelle, the Netherlands. Picture Pim Wolf.
1cy argenteus in August, ringed in Belgium. (90559 bytes)Herring Gull JK 1cy (argenteus), September 19 2009, Westkapelle, the Netherlands.
1cy argenteus in August, ringed in Belgium. (90559 bytes)Herring Gull JN 1cy (argenteus), September 10 2009, Westkapelle, the Netherlands.
1cy argenteus in August, ringed in Belgium. (90559 bytes)Herring Gull NR 1cy (argenteus), September 01 2010, Westkapelle, the Netherlands.
1cy argenteus in August, ringed in Belgium. (90559 bytes)Herring Gull RH 1cy (argenteus), September 23 2009, Barneveld, the Netherlands.
1cy argenteus in August, ringed in Belgium. (90559 bytes)Herring Gull UZ 1cy (argenteus), September 21 2009, Westkapelle, the Netherlands.
1cy argenteus in September, ringed in the UK. (69121 bytes)Herring Gull T2 1cy (argenteus), September 06 2006, Scheveningen, the Netherlands. Picture Renee & George.
1cy argenteus in September, ringed in the UK. (69121 bytes)Herring Gull T5 1cy (argenteus), September 05 2006, Mt St Guibert, Belgium. Picture Marc Fasol.
1cy argenteus in September, ringed in the Netherlands. (81066 bytes)Herring Gull 5.413.032 1cy (argenteus), September 24 2004, IJmuiden, the Netherlands (52.27N 04.33E). 
1cy argenteus in September, ringed in the Netherlands. (84423 bytes)Herring Gull 5.413.050 1cy (argenteus), September 18 2004, IJmuiden, the Netherlands (52.27N 04.33E). 
1cy argenteus in September, ringed in the Netherlands. (84424 bytes)Herring Gull 5.413.051 1cy (argenteus), September 18 2004, IJmuiden, the Netherlands (52.27N 04.33E). 
juvenile LBBG in October, ringed in Norway. (131273 bytes)Herring Gull 5.419.242 1cy (argenteus), September 29 2007, Westkapelle, the Netherlands.
1cy argenteus in August, ringed in Belgium. (90559 bytes)Herring Gull 5.429.056 1cy (argenteus), September 20 2010, Westkapelle, the Netherlands.
1cy argenteus in August, ringed in Belgium. (90559 bytes)Herring Gull 5.429.070 1cy (argenteus), September 01 2010, Neeltje Jans, the Netherlands.
1cy argenteus in August, ringed in Belgium. (90559 bytes)Herring Gull 5.429.097 1cy (argenteus), September 23 2010, Westkapelle, the Netherlands.
1cy argenteus in December, ringed in the Netherlands. (119951 bytes)Herring 5.429.2871cy (argenteus), 2010-2011, IJmuiden, the Netherlands.
1cy argenteus in December, ringed in the Netherlands. (119951 bytes)Herring 5.463.357 1cy (argenteus), September 03-11 2011, IJmuiden, the Netherlands.
1cy argenteus in August, ringed in Belgium. (90559 bytes)Herring Gull 5.463.365 1cy (argenteus), September 03-11 2011, IJmuiden, the Netherlands.
1cy argenteus in August, ringed in Belgium. (90559 bytes)Herring Gull 5.463.382 1cy (argenteus), September 11 2011, IJmuiden, the Netherlands.
1cy argenteus in August, ringed in Belgium. (90559 bytes)Herring Gull 5.463.387 1cy (argenteus), September 11 2011, IJmuiden, the Netherlands.
ad LBBG in winter, ringed in the Netherlands. (65647 bytes)Herring Gull (argenteus) 1cy NLA 5.472.728 September 26 2012, Boulogne-sur-Mer, NW France. Picture: Jean-Michel Sauvage.
adult argenteus in October, ringed in the Netherlands. (79042 bytes)Herring Gull 6.166.442 1cy (argenteus), September 12 2010, IJmuiden, the Netherlands.
adult argenteus in October, ringed in the Netherlands. (79042 bytes)Herring Gull 6.166.566 1cy (argenteus), September 20 2010, IJmuiden, the Netherlands.
adult argenteus in October, ringed in the Netherlands. (79042 bytes)Herring Gull 6.169.025 1cy (argenteus), September 22 2011, IJmuiden, the Netherlands.
adult argenteus in October, ringed in the Netherlands. (79042 bytes)Herring Gull 6.169.3xx 1cy (argenteus), September 17 2011, Leiden, the Netherlands.
1cy argenteus in November, ringed in Belgium. (25637 bytes)Herring Gull 6.170.697 1cy (argenteus), September 03 2012, Katwijk, the Netherlands.
1cy argenteus in September (65624 bytes)Herring Gull (argenteus) 1cy NLA 6.173.969 September 23 2013, Katwijk, the Netherlands.
1cy argenteus in September (65624 bytes)Herring Gull (argenteus) 1cy NLA 6.173.998 September 19 2013, Katwijk, the Netherlands.
unringed 1cy Herring Gulls
1cy argenteus in September (65624 bytes)Herring Gull (argenteus) 1cy, September 25 2013, Katwijk, the Netherlands. 
Replaced coverts.
1cy argenteus in September (65624 bytes)Herring Gull 1cy (argenteus), September 21 2004, Scheveningen, the Netherlands. 
Replaced coverts.
1cy argenteus in September (65624 bytes)Herring Gull 1cy (argenteus), September 01 2006, IJmuiden, the Netherlands (52.27N 04.33E). 
GC 2nd gen like.
1cy argenteus in September (65624 bytes)Herring Gull (argenteus) 1cy, September 17 2013, Katwijk, the Netherlands. 
Ring-tailed Herring Gulls.
1cy argenteus in September (65624 bytes)Herring Gull (argenteus) 1cy, September 17 2013, Katwijk, the Netherlands. 
Normal tail patterns.