Herring Gull- Zilvermeeuw (argentatus & argenteus)

(last update: December 15, 2011 )

Herring Gull - 3cy July

Introduction

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.

Comparing plumages in July

July, mid-summer, all birds are in complete moult. The combination of very worn old feathers and recently replaced new together with moult gaps in many feather tracts make many birds look like fluffy messy feather balls rather than birds. By late July, many local populations see a new cohort of very fresh juveniles added to the group.

2cy argenteus in February, ringed in the Netherlands. (27385 bytes) 2cy argenteus in February, ringed in the Netherlands. (27385 bytes)
Herring Gull (argenteus) 1CY, July 30 2014, IJmuiden, the Netherlands (Mars Muusse). Herring Gull (argenteus) 1CY, July 30 2014, IJmuiden, the Netherlands (Mars Muusse).
ID 1CY birds in July: birds recently left the colony in very fresh juvenile plumage. Easily told from 2CY birds by the full hand of pointed, first generation primaries showing a pale window in the inner feathers. No moult in primaries, no moult in secondaries and no moult in tail.
2cy argenteus in February, ringed in the Netherlands. (27385 bytes) 2cy argenteus in February, ringed in the Netherlands. (27385 bytes)
Herring Gull (argenteus) 2CY, July 15 2009, Boulogne-sur-Mer, France (Jean-Michel Sauvage). Herring Gull 2CY, July 31 2015, Noordwijk, the Netherlands (Mars Muusse).
ID 2CY birds in July: messy looking birds, showing moult gaps in many feather tracts by July. Inner primaries are new, overall grey but with brown hue. Central primaries have darker outerwebs, gradually dissolving in paler innerwebs and are brownish, not blackish as in in 3CY birds. Moult in primaries, and by late July often starts moult in secondaries and tail as well. New feathers in coverts are heavily barred, often densely marbled in the greater coverts; new feathers not adult-like plain silvery grey as in 3CY birds. Iris normally brown.
2cy argenteus in February, ringed in the Netherlands. (27385 bytes) 2cy argenteus in February, ringed in the Netherlands. (27385 bytes)
Herring Gull (argenteus) 3Y, July 30 2014, IJmuiden, the Netherlands (Mars Muusse). Herring Gull 3Y, July 18 2013, Noordwijk, the Netherlands (Mars Muusse).
ID 3CY birds in July: combination of adult-like features and immature markings. Told from one year younger 2CY birds by pattern on fresh inner primaries, which appear adult-like grey. Central primaries have blackish outerwebs, sharply set from grey innerwebs. Moult in primaries, and by last days of July often starts moult in secondaries and tail as well. New feathers in coverts are adult-like plain silvery grey. Iris normally pale, blueish with dense speckling in some birds.
Told from one year older 4CY birds by the pattern on the old feathers. Secondaries are old 2nd generation, showing large brown centres on all feathers and only thin white fringe on the tips. Old, second generation tail with broad band and proximal barring. Secondaries on 4CY birds are also old, but already 3rd generation, with grey centres and broad white tips, like in adults but many birds show variable amount of brown on at least some of the secondaries. Normally less black in 3rd generation tail, or tail almost completely white in many argenteus. Also, 4CY birds normally have more adult-like bare parts (bill, iris).
2cy argenteus in February, ringed in the Netherlands. (27385 bytes) 2cy argenteus in February, ringed in the Netherlands. (27385 bytes)
Herring Gull 4CY, July 31 2014, Noordwijk, the Netherlands (Mars Muusse). Herring Gull 4CY, July 30 2014, IJmuiden, the Netherlands (Mars Muusse).
ID 4CY birds in July: exact ageing can be difficult in many birds, and these are better left grouped as 'sub-adults'. Still, the combination of old and new feathers may give hints, especially the pattern on old feathers. New 4th generation inner primaries growing in by July are adult-like grey with slightly more black on the central primaries in this age class than full adults will show. Upperparts and new coverts appear adult-like grey as well, but new central tertials and new central greater coverts often show dark lining or markings again (probably more apparent in argentatus than in argenteus).
Best clue for ageing 4CY birds are old retained feathers: outer primaries are faded brown, with no or small mirror on P10. Secondaries are grey with pale tips, but many of these old secondaries show brown markings. Old outer primary coverts have extensive brown centres. Many birds show old lower tertials and the lesser coverts; these old feathers are worn but the brown markings in these locations are obvious in many birds.
2cy argenteus in February, ringed in the Netherlands. (27385 bytes) 2cy argenteus in February, ringed in the Netherlands. (27385 bytes)
Herring Gull (argenteus) 5CY, July 30 2014, IJmuiden, the Netherlands (Mars Muusse). Herring Gull (argenteus) 5CY, July 30 2014, IJmuiden, the Netherlands (Mars Muusse).
ID 5CY birds in July: exact ageing can be difficult in many birds, and these are better left grouped as 'sub-adults'. Also, many 5CY birds will probably go unnoticed and simply labelled 'adult'. Birds with overall adult plumage, both in old and new feathers, which combine this adult-like plumage with single blackish markings in greater primary coverts or a single spot in the tail are very likely 5CY (based ringed birds). 5CY argentatus seems to show immature markings more often than 5CY argenteus.
2cy argenteus in February, ringed in the Netherlands. (27385 bytes) 2cy argenteus in February, ringed in the Netherlands. (27385 bytes)
Herring Gull (argenteus) adult, July 25 2010, Texel, the Netherlands (Maarten van Kleinwee). Herring Gull (argenteus) 6CY, July 29 2011, Barneveld, the Netherlands (Maarten van Kleinwee).
ID 5+CY birds in July: exact ageing only when ring data are available.

 

Tables:

Small surveys of primary moult score in France and Finland are presented below:

Remaining old primaries in 3cy argenteus at Le Portel - Boulogne/Mer, July 10 2002.
P5-P10 old 1
<P6 old* 2
P6-P10 old 23
P7-P10 old 88
P8-P10 old 59
P9-P10old 7 (P5 or P6 full grown)
P10 old -
n = 180; m old P= 3.8; SD old P = 0.79
The shortest old primary was scored.
* = in the folded wing, at least P5 was still present, but maybe P4 as well.

 

Primary moult score of 3cy argentatus Herring Gull, at Tampere landfill, Finland (61.33N, 23.59E) on July 10 2003.
. P4 fg P5 fg P6 fg ? fg n:
P6-P10 - - - 2 2
P7-P10 9 1 - 4 14
P8-P10 - 16 - 3 19
P9-P10 - - 2 - 2
n: 9 17 2 9 37
n = 37; m old P = 3.4; SD old P = 0.69.
Survey at Tampere, landfill, in resting group at 'the saddle', about 50 3cy Herring Gulls, probably 100% argentatus.
P6-P10 = P6-P10 are still old and present.
? fg = fully grown not known. Fully grown primary score most probably P6 or less.
fg = fully grown. In our field surveys, a primary is 'fully grown' when it exceeds the previous feather in the folded wing. Actually,  such 'fully grown' feathers may have to grow a little, but under field circumstances, it's very difficult to find out if the waxy sheath, which is the standard measurement for fully grown primaries, is still present. 

 

Primary moult score of 3cy argentatus Herring Gull, at Tampere landfill, Finland (61.33N, 23.59E) on July 13 2003, 15:00 h.
. P4 fg P5 fg P6 fg ? fg n:

P5-P10

- - - 1 1
P6-P10 - - - - -
P7-P10 2 1 - 8 11
P8-P10 1 40 3 25 69
P9-P10 - 1 9 - 10
n: 3 42 12 34 91
n = 91; m old P = 3.0; SD old P = 0.58.
Survey at Tampere, landfill, in resting group at 'Bio I'.

below: some unringed Herring Gulls, probably all local argenteus from continental Europe, from the last day of July in the Netherlands.

2cy argentatus in July. (76431 bytes)Herring Gull 3CY, July 31 2015, Noordwijk, the Netherlands. 2cy argentatus in July. (76431 bytes)Herring Gull 3CY, July 31 2015, Noordwijk, the Netherlands.
2cy argentatus in July. (76431 bytes)Herring Gull 3CY, July 31 2015, Noordwijk, the Netherlands. 2cy argentatus in July. (76431 bytes)Herring Gull 3CY, July 31 2015, Noordwijk, the Netherlands.
2cy argentatus in July. (76431 bytes)Herring Gull 3CY, July 31 2015, Noordwijk, the Netherlands. 2cy argentatus in July. (76431 bytes)Herring Gull 3CY, July 31 2015, Noordwijk, the Netherlands.
2cy argentatus in July. (76431 bytes)Herring Gull 3CY, July 31 2015, Noordwijk, the Netherlands. 2cy argentatus in July. (76431 bytes)Herring Gull 3CY, July 31 2015, Noordwijk, the Netherlands.

rings argenteus: UK
1cy argenteus in November, ringed in Belgium. (25637 bytes)Herring Gull A7JG 3cy (argenteus), 2011 & March-July 2012, Boulogne/Mer, France (50.42N,1.34E). Picture: J-M Sauvage.
rings argenteus: France
2cy argenteus in March, ringed in France. (57822 bytes)Herring Gull M3A, 3cy (argenteus), July 07 2009, Boulogne/Mer, France (50.42N,1.34E). Picture: J-M Sauvage.
rings argenteus: Belgium
3cy argenteus in July, ringed in Belgium. (66484 bytes)Herring Gull H-xxxxxx 3cy (argenteus), July 11 2002, Boulogne/Mer, France (50.42N,1.34E).
rings argenteus: the Netherlands
2cy argenteus in February, ringed in the Netherlands. (27385 bytes)Herring Gull 5W 3cy (argenteus), July07 2009, Boulogne/Mer, France. Photo: J-M Sauvage.
1cy argenteus in November, ringed in Belgium. (25637 bytes)Herring Gull (argenteus) Y.BDS 1CY-4CY, September 2012, July 2014 & February 2015, IJmuiden, the Netherlands.
2cy argentatus in July. (76431 bytes)Herring Gull (argenteus) NLA 6.173.970 3CY, July 31 2015, Noordwijk, the Netherlands.
3cy argenteus in July, ringed in the Netherlands. (83725 bytes)Herring Gull 5.412.501 3cy (argenteus), July 09 2004, IJmuiden, the Netherlands (52.27N 04.33E)
rings argentatus: Poland
3cy argentatus in July, ringed in Poland. (75760 bytes)Herring Gull DN11467 3cy (argentatus), July 10 2003, Tampere, Finland (61.31N, 23.43E).
rings argentatus: Sweden
3cy argentatus in July, ringed in Sweden. (77759 bytes)Herring Gull 90A12473 3cy (argentatus), July 15 2003, Tampere, Finland (61.31N, 23.43E).
rings argentatus: Finland
3cy argentatus in July, ringed in Finland. (74898 bytes)Herring Gull C029N 3cy (argentatus), July 16 2003, Tampere, Finland (61.31N, 23.43E).
3cy argentatus in July, ringed in Finland. (75582 bytes)Herring Gull C110P 3cy (argentatus), July 10-14 2003, Tampere, Finland (61.31N, 23.43E).
3cy argentatus in July, ringed in Finland. (71834 bytes)Herring Gull C136V 3cy (argentatus), July 16 2003, Tampere, Finland (61.31N, 23.43E).
3cy argentatus in July, ringed in Finland. (74907 bytes)Herring Gull C6C98 3cy (argentatus), July 15 2003, Tampere, Finland (61.31N, 23.43E).
3cy argentatus in July, ringed in Finland. (71012 bytes)Herring Gull C6V34 3cy (argentatus), July 15-16 2003, Tampere, Finland (61.31N, 23.43E).
3cy argentatus in July, ringed in Finland. (74127 bytes)Herring Gull C6V77 3cy (argentatus), July 16 2003, Tampere, Finland (61.31N, 23.43E).
3cy argentatus in July, ringed in Finland. (77523 bytes)Herring Gull C7N54 3cy (argentatus), July 14-16 2003, Tampere, Finland (61.31N, 23.43E).
3cy argentatus in July, ringed in Finland. (73986 bytes)Herring Gull CE942 3cy (argentatus), July 10-15 2003, Tampere, Finland (61.31N, 23.43E).
3cy argentatus in July, ringed in Finland. (75251 bytes)Herring Gull HT-x77607 3cy (argentatus), July 15 2003, Tampere, Finland (61.31N, 23.43E).
3cy argentatus in July, ringed in Finland. (74812 bytes)Herring Gull HT-224010 3cy (argentatus), July 15 2003, Tampere, Finland (61.31N, 23.43E).
 
unringed 3cy Herring Gulls
Herring Gull 3CY, July 09 2013, Katwijk, the Netherlands. PMS: P3/P6.
Herring Gull 3CY, July 09 2013, Katwijk, the Netherlands. PMS: P4/P7.
Herring Gull 3CY, July 09 2013, Katwijk, the Netherlands. PMS: P5/P7.
Herring Gull 3CY, July 09 2013, Katwijk, the Netherlands. PMS: P5/P8.
Herring Gull 3CY, July 09 2013, Katwijk, the Netherlands. PMS: P5/P8.
Herring Gull 3CY, July 09 2013, Katwijk, the Netherlands. PMS: P5/P8.
2cy argentatus in July. (70842 bytes)Herring Gull 3CY, July 18 2013, Katwijk, the Netherlands. PMS: P5/P8.
2cy argentatus in July. (70842 bytes)Herring Gull 3CY, July 18 2013, Katwijk, the Netherlands. PMS: P5/P8.
2cy argentatus in July. (70842 bytes)Herring Gull 3CY, July 18 2013, Katwijk, the Netherlands. PMS: P6/P8.
2cy argentatus in July. (70842 bytes)Herring Gull 3CY, July 18 2013, Katwijk, the Netherlands. PMS: P5/P8.
2cy argentatus in July. (70842 bytes)Herring Gull 3CY, July 09 2013, Katwijk, the Netherlands. PMS: P6/P9.
2cy argentatus in July. (70842 bytes)Herring Gull 3CY, July 18 2013, Katwijk, the Netherlands.
Herring Gull 3CY, July 30 2014, IJmuiden, the Netherlands. PMS: P6/P8.
2cy argentatus in July. (76431 bytes)Herring Gull 3CY, July 31 2015, Noordwijk, the Netherlands.
2cy argentatus in July. (76431 bytes)Herring Gull 3CY, July 31 2015, Noordwijk, the Netherlands.
2cy argentatus in July. (76431 bytes)Herring Gull 3CY, July 31 2015, Noordwijk, the Netherlands.
2cy argentatus in July. (76431 bytes)Herring Gull 3CY, July 31 2015, Noordwijk, the Netherlands.
2cy argentatus in July. (76431 bytes)Herring Gull 3CY, July 31 2015, Noordwijk, the Netherlands.
2cy argentatus in July. (76431 bytes)Herring Gull 3CY, July 31 2015, Noordwijk, the Netherlands.
2cy argentatus in July. (76431 bytes)Herring Gull 3CY, July 31 2015, Noordwijk, the Netherlands.
2cy argentatus in July. (76431 bytes)Herring Gull 3CY, July 31 2015, Noordwijk, the Netherlands.
unringed 3cy Herring Gulls (argentatus)
possible 3cy argentatus/cachinnans in July. (71070 bytes)Herring Gull? 3cy?, July 15 2003, Tampere, Finland (61.31N, 23.43E).
3cy argentatus in July. (75240 bytes)Herring Gull 3cy (argentatus), July 14 2003, Tampere, Finland (61.31N, 23.43E).
3cy argentatus in July. (67849 bytes)Herring Gull 3cy (argentatus), July 14 2003, Tampere, Finland (61.31N, 23.43E).
3cy argentatus in July. (75193 bytes)Herring Gull 3cy (argentatus), July 14 2003, Tampere, Finland (61.31N, 23.43E).
3cy argentatus in July. (74118 bytes)Herring Gull 3cy (argentatus), July 15 2003, Tampere, Finland (61.31N, 23.43E).
3cy argentatus in July. (73291 bytes)Herring Gull 3cy (argentatus), July 14 2003, Tampere, Finland (61.31N, 23.43E).