Herring Gull- Zilvermeeuw (argentatus & argenteus)

(last update: December 15, 2011 )

Coordinators:
Jean-Michel Sauvage (France)
Mars Muusse (the Netherlands)

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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
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hg 3cy May
hg 3cy June
hg 3cy July
hg 3cy August
hg 3cy September
hg 3cy October
hg 3cy November
hg 3cy December

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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 argenteusand 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. 

Herring Gulls (Larus argentatus argenteus) at IJmuiden, the Netherlands

Read more about the location: IJmuiden.

Observations of ringed birds can be sent to Kees Camphuysen at NIOZ, Texel (mail camphuys at nioz dot nl). Click the Excel logo for the life history of Herring Gull Y.AAK and find the report of earlier sightings.

Read more about the 2007 ring activities by Fred Cottaar & Kees Verbeek on Forteiland, IJmuiden. (Word document 4,5Mb, in Dutch with tables and plots)

Read more on the NIOZ website about ringing projects on Texel, Vlieland, Leiden and the Dutch delta administrated by Kees Camphuysen.

Read more about the history of ringing programmes in Holland and the results throughout the years. An article prepared for the magazine Sula by Kees Camphuysen (in Dutch, with English summary; PDF-file 1160 Kb).

The IJmuiden Ringing Team (Fred Cottaar & Kees Verbeek) have ringed Herring Gulls and Lesser Black-backed Gulls at Forteiland, IJmuiden in 2008-2010. This time green darvic rings have been attached, starting with Y for both species (so codes read Y.xxx).
Early in the season of 2008, 44 adult Lesser Black-backed Gulls and 16 Herring Gulls were caught at the nests and ringed. Late June 2008 about 35 juveniles (of both species) were caught and ringed as well by Fred and Kees.

The pages on this website show examples of birds from this IJmuiden project. All observations of ringed birds from these projects can be sent to Kees Camphuysen at NIOZ, Texel (mail camphuys at nioz dot nl). By clicking the thumbnails right, you will find enlarged pictures of these birds. By clicking the Excel logo (right box) you will find an example Excel Sheet with the reports of earlier sightings of adult Herring Gull Y.AAK from the excel database, as will be sent to you after reporting rings to Kees Camphuysen.

Forteiland - IJmuiden.

Many Herring and Lesser Black-backed Gulls used to breed along the coast in the dunes, but nowadays most are roof-top breeding birds. Buildings with adequate roof-tops in the fish-industry complex of IJmuiden have been occupied, and recently gulls are spreading to roof-tops in cities as well. The change in breeding habitat has much to do with predation of Red Fox in the dunes.

Forteiland (see picture) is an isle where the Fox was not found in the 1980's. Up to 1988 the colony increased but then, in the breeding season of 1988, one Fox managed to reach this island. Apparently, gulls have good memories as the island was abandoned for 15 years; it lasted to 2003 when finally the island was occupied by gulls again. In 2007, number of breeding pairs approximately levels numbers in 1988. However, Lesser Black-backed Gull has now become the common species, while this used to be Herring Gull in the 1980's.

Nowadays, Forteiland is the last place where ground breeders can be found at IJmuiden. Due to construction works and disturbance of some colonies, the importance of the Forteiland colony is growing. From 2003, numbers of breeding birds increase annually. Ring recoveries show birds arrive from other colonies in IJmuiden, but also from Moerdijk, Maasvlakte and Texel. For the next years, more construction works are planned in IJmuiden harbour, e.g. for the Middensluis Complex, unfortunately hosting a large colony of both Herring and Lesser Black-backed Gulls. Hence, for the coming years it is expected many more gulls will search for new nesting areas, and will find their way to Forteiland.

1cy Herring Gull August: tables

Table 1: Scapular and wing-covert moult scores for ringed 1cy August Herring Gulls.

Scatterplot above: % moult score in total scapular region plotted against date for the month August (01 July = day 1). Data from 1st table (above).
1 = taxon argentatus (S Finland, Sweden); 2 = taxon argenteus (Belgium, the Netherlands).

rings argenteus: the Netherlands