Herring Gull - Zilvermeeuw (L. argentatus)

(last update: 28-12-2006)

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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

Herring Gull - 1cy August

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 August

In juvenile plumage, the head and under-parts are streaked grey-brown, rather pale on forehead and throat and with dark ear-coverts. The mantle and scapulars 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, obvious on the outer greater coverts as well in western populations (British argenteus). Some 1cy argentatus (e.g. this argenteus and this argentatus) may have the outer greater coverts with extensive dark centres, lacking obvious notching and thin fringes on the tertials, like in michahellis. On average, the tertials have an obvious notched pale fringe and transversal bar. Again, 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. 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. 
From 1cy July onwards, the mantle and upper scapulars may be moulted to second generation feathers, showing an anchor pattern and a dark base. 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 do not start the post-juvenile moult before the end of the month. Below, we included a table of 23 ringed Herring Gull, of which 9 started the post-juvenile moult before 15 August (about 40%). Most advanced birds have over 10 (small) upper scapulars and mantle feathers replaced. In these birds, active moult is obvious by the large moult gaps, showing the bases of the underlying feathers. 

1cy Herring Gull August: tables

CODE TAXON DATE SIDE RING TT & COVS 2g   TOTAL
          # US LS SCAPS
SFH A 6-aug L C268Y 0 F F F
SFH A 6-aug R HT-222865 0 E E E
SFH A 6-aug L HT-2XXX33 0 E F E
SFH A 7-aug R C198U 0 F F F
SFH A 7-aug R C9V59 0 E F E
SFH A 11-aug nn C9S27 0 E E E
SFH A 11-aug nn C266U 0 F F F
SFH A 8-aug L C8J87 0 F F F
SFH A 9-aug L C280P 0 F F F
SFH A 10-aug L C211J 0 F F F
SFH A 10-aug L C272P 0 E F E
SFH A 10-aug L C9V40 0 E F E
SFH A 11-aug L C265H 0 F F F
SFH A 11-aug L C9C37 0 F F F
SFH A 11-aug nn C9H66 0 F F F
SFH A 12-aug R C167K 0 F F F
SFH A 12-aug nn HT-229068 0 E F E
SWS A 14-aug L DA 53945 0 F F F
BLB B 15-aug R H-131304 0 E E E
BLB B 15-aug nn H-131183 0 F F F
BLB B 15-aug nn H-128369 0 E F E
NLA B 15-aug nn 5.X86.641 0 F F F
NLA B 12-aug nn 6.125.999 0 F F F
post-juvenile moult score of several ringed L. argentatus argentatus in 2002 and argenteus from 2003. 
Code SFH: ringed in Finland; SWS: ringed in Sweden; BLB: ringed in Belgium; NLA: ringed in the Netherlands.
Taxon A: argentatus; B argenteus.
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.

 

 

 
1cy argenteus in August, ringed in Belgium. (90559 bytes)Herring Gull H-131304 1cy (argenteus), August 15 2003, Westkapelle, the Netherlands (51.33N, 03.25E).
1cy argenteus in August, ringed in the Netherlands. (89062 bytes)Herring Gull 6.125.999 1cy (argenteus), August 12 2004, Brouwersdam, the Netherlands.
1cy argentatus in August, ringed in Finland. (93512 bytes)Herring Gull C167K 1cy (argentatus), August 12 2002, Tampere, Finland (61.31N,23.43E).
1cy argentatus in August, ringed in Finland. (74366 bytes)Herring Gull C198U 1cy (argentatus), August 06 2002, Tampere, Finland (61.31N,23.43E).
1cy argentatus in August, ringed in Finland. (85943 bytes)Herring Gull C211J 1cy (argentatus), August 09 2002, Tampere, Finland (61.31N,23.43E).
1cy argentatus in August, ringed in Finland. (71800 bytes)Herring Gull C265H 1cy (argentatus), August 08 2002, Tampere, Finland (61.31N,23.43E).
1cy argentatus in August, ringed in Finland. (76157 bytes)Herring Gull C268Y 1cy (argentatus), August 06 2002, Tampere, Finland (61.31N,23.43E).
1cy argentatus in August, ringed in Finland. (88543 bytes)Herring Gull C272P 1cy (argentatus), August 10 2002, Tampere, Finland (61.31N,23.43E).
1cy argentatus in August, ringed in Finland. (59965 bytes)Herring Gull C280P 1cy (argentatus), August 09 2002, Tampere, Finland (61.31N,23.43E).
1cy argentatus in August, ringed in Finland. (81022 bytes)Herring Gull C8J87 1cy (argentatus), August 10 2002, Tampere, Finland (61.31N,23.43E).
1cy argentatus in August, ringed in Finland. (72709 bytes)Herring Gull C9C37 1cy (argentatus), August 11 2002, Tampere, Finland (61.31N,23.43E).
1cy argentatus in August, ringed in Finland. (82920 bytes)Herring Gull C9V40 1cy (argentatus), August 10 2002, Tampere, Finland (61.31N,23.43E).
1cy argentatus in August, ringed in Finland. (90069 bytes)Herring Gull C9V59 1cy (argentatus), August 07 2002, Tampere, Finland (61.31N,23.43E).
1cy argentatus in August, ringed in Sweden. (67561 bytes)Herring Gull DA 53945 1cy (argentatus), August 14 2002, Gotenborg, Sweden.
1cy argentatus in August, ringed in Finland. (75649 bytes)Herring Gull HT-222865 1cy (argentatus), August 06 2002, Tampere, Finland (61.31N,23.43E).
1cy argentatus in August, ringed in Finland. (63788 bytes)Herring Gull HT-2xxx33 1cy (argentatus), August 06 2002, Tampere, Finland (61.31N,23.43E).
1cy argenteus in August (79837 bytes)Herring Gull 1cy (argenteus), August 18 2001, Dintelhaven - Maasvlakte, the Netherlands (51.58N-04.02E). 
1cy argenteus in August (79569 bytes)Herring Gull 1cy (argenteus), August 18 2001, Dintelhaven - Maasvlakte, the Netherlands (51.58N-04.02E).
1cy argenteus in August (81789 bytes)Herring Gull 1cy (argenteus), August 18 2001, Dintelhaven - Maasvlakte, the Netherlands (51.58N-04.02E). 
1cy argenteus in August (80983 bytes)Herring Gull 1cy (argenteus), August 18 2001, Dintelhaven - Maasvlakte, the Netherlands (51.58N-04.02E).
1cy argentatus in August. (53708 bytes)Herring Gull 1cy (argentatus), August 06 2002, Tampere, Finland (61.31N, 23.43E).
1cy argentatus in August. (94231 bytes)Herring Gull 1cy (argentatus), August 06 2002, Tampere, Finland (61.31N,23.43E).
1cy argentatus in August. (82031 bytes)Herring Gull 1cy (argentatus), August 09 2002, Tampere, Finland (61.31N, 23.43E).
1cy argentatus in August. (71124 bytes)Herring Gull 1cy (argentatus), August 10 2002, Tampere, Finland (61.31N, 23.43E).
1cy argentatus in August. (62968 bytes)Herring Gull 1cy (argentatus), August 14 2002, Gotenborg, Sweden.
1cy argentatus in August. (58288 bytes)Herring Gull 1cy (argentatus), August 14 2002, Gotenborg, Sweden.
1cy argentatus in August. (67310 bytes)Herring Gull 1cy (argentatus), August 14 2002, Gotenborg, Sweden.