Herring Gull- Zilvermeeuw (argentatus & argenteus)

(last update: 27-2-2007)


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

(3 images) Herring Gull C6C98 3cy (argentatus), July 15 2003, Tampere, Finland (61.31N, 23.43E).

3cy argentatus, ringed white C6C98 as pullus on July 07 2001 in Vkoski, Finland (61.16N 24.14E). There are a dozen of observations from Tampere dump. The complete moult is well underway with most wing-coverts and the inner primaries recently moulted. Primary P7 has been dropped and P8-P10 are still second generation. P1-P5 are fully grown third generation flight-feathers, with a complete band on P5.

From June to October, a complete moult will bring 3cy argentatus in so-called "third winter" plumage. By August, the first neat streaks can be found on the crown and neck. After the complete moult is finished in autumn, the head will show extensive 'winter streaking', often neat fine streaking in argentatus and mottled brown contrasting with the white breast as in an executioner's hood in many argenteus. The scapulars and mantle are pale adult-like grey, although some individuals may show an immature pale brown hue or arrow-head patterns on the lower scapulars. 
By June, 3cy argentatus are moulting new third generation plain grey wing-coverts, starting with the outermost median coverts. Contrary many argenteus, 3cy argentatus often show immature patterns on the inner greater coverts, inner and outermost median coverts and upper tertials (the first moulted wing-coverts and tertials in the complete summer moult). When inner greater coverts and median coverts were included in the partial autumn moult in 2cy, these feathers are left out of the moult sequence in the very early moult-stage. By the end of the complete moult (October), all wing-coverts have been replaced.

During the summer, the primaries are moulted to third generation. In argenteus, the first inner primaries are dropped by late May and the outer primary P10 will be dropped by late August. The primary moult is completed  by late-October, in argenteus, when the new outer primary P10 is fully grown. Preliminary data from Tampere, Finland, indicate 3cy argentatus from this region are not delayed in primary moult compared to argenteus from continental NW Europe. The third generation primaries are clearly adult-like, with inner primaries P1-P3 plain grey with a white tip. The outer-wing shows a clear black triangle, extending on the greater primary coverts. From P4 outwards, the primaries show black sub-terminal markings. The white primary tips are obvious in the inner primaries, but are only poor developed on third generation P9 and P10. The third generation P10 normally shows a small white mirror (lacking in some birds). The new tail-feathers will be predominantly white, with clear immature black markings. The iris turns pale yellow in summer in most argenteus (July-August), but quite some argentatus will keep the iris amber to dark brown.

In the tables below, the primary moult scores of 3cy July argentatus in Finland can be read:

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:


- - - 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'.