Herring Gull- Zilvermeeuw (argentatus & argenteus)

(last update: December 15, 2011 )

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

Home

hg rings

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

Herring Gull - 4cy /sub-adults November

Thumbnails in the column right illustrate plumage characteristics of ringed and unringed immature Herring Gull (4CY & 5CY birds) for the month of November.

Some remarks on ID of argentatus vs argenteus

Herring Gulls breeding in Europe are variable in upper-part coloration, measurements and wingtip pattern. Argentatus,breeding in Scandinavia, is large and snouty, has grey upper-parts, shows limited black in the wingtip and northern populations may migrate 2000+ km’s south in autumn.
Western populations are called British Herring Gull argenteus, which are smaller, have paler grey upper-parts, more black in the wingtip and many do not migrate at all, or have short distance dispersion along the Atlantic coast. There is a cline between the Herring Gull populations in the North Sea bassin.
Most of this general picture was constructed by extensive research by the Norwegian ornithologist E. K. Barth, published as Contribution No. 86, Zoological Museum, University of Oslo, called "The circumpolar systematics of Larus argentatus and Larus fuscus with special reference to the Norwegian populations".

Already in the 1960’s, Barth’s research described variation in upper-part grey tones and in wingtip patterns within any of the single populations. Due to indivudual variation, at locations where both taxa are present or expected, it is often only possible to assign individual bird to either taxon argentatus or argenteus if birds are ringed as chick, or when classic birds in the extremes of the continuum are observed at the right location, in the right season.
Here we show some example birds from various populations.

Upperpart grey tone in adults

Reserach by Barth introduced the split in Herring Gull into argentatus and argenteus. Below, a map with clustered column charts for NE populations, for various locations. Click the thumbnails on the map to enlarge graphs (figures have been prepared with most care, yet I take full responsibility for any errors in charts).

Wingtip patterns in adults

The differences between typical western argenteus from the U.K. and northern Scandinavian argentatus is rather straightforward on primary pattern P5-P10. However, there is a gradient and overlap in features of birds from populations in northern Germany, Denmark and southern Norway. 
Identification is even more challenging in birds from Baltic populations, which show both characteristics of argenteus and argentatus, but sometimes also of the southern taxa michahellis and cachinnans.
Adult birds from the western populations argenteus show more black in the outer primaries, compared to northern argentatus. In argenteus, P5 normally shows small black sub-terminal markings, concentrated on the outer-web as a clear-cut black angular spot and in some birds extending on the inner-web as a diffuse streak. There may be some black on P4 as well, although this might be a clue for near-adult birds. In argentatus, especially from far northern Scandinavia, the black marking on P5 is completely lacking or is very limited and diffuse.
Argenteus often has a black sub-terminal band on the top of P10, dividing the tip from the mirror. If the black sub-terminal band on P10 is broken, there is often still black on the inner and outer-web's edge of P10. Normally argentatus lacks sub-terminal markings on the outer-web of P10.

Baltic argentatus often have the black marking on P5 confined to the outer-web as a single rectangular small black square, with well-defined borders (not diffuse as in most Finnmark birds). In most Baltic birds, the white tip of P10 fully merges with the mirror, without a single sign of a sub-terminal band. The greyish-white 'tongue' on the inner-web is often broad and continues far down P10, almost creating a thayeri pattern on P10. The shape of the division line between greyish tongue and black outer-web can be an identification clue: In cachinnans this division line often makes a strong angular curve and has a smooth straight line, unlike the pattern of Herring Gulls, which often show a "saw-blade" motive or otherwise much irregularities along the division line. Sometimes wear of the outer primaries may be useful as a first indication of origin: An early moulting species as cachinnans on average show more abrasion in the feathers than later moulting argentatus.

Especially birds from north Scandinavian Finnmark may show the characteristic 'thayeri' pattern in the outer primaries P9 and P10 (column 5 of tip pattern P9 in the table). This pattern is named after the Thayer's Gull, which often shows a particular pattern in the outer primaries: the mirror and the white tip merge and are connected to the pale inner-web (see this image). In other words: the black medial band of the outer-web doesn't fully reach the edge of the inner-web and there is no sub-terminal band. In Thayer's Gull this pattern may be very obvious and, together with the 'string of pearls' may be indicative for identification. 

rings argentatus: Germany

rings argentatus: Russia