Herring Gull- Zilvermeeuw (argentatus & argenteus)

(last update: 10-1-2007)

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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

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 C527R 2cy (argentatus), August 11 2002, Tampere, Finland (61.31N,23.43E).

A 2cy argentatus, trapped and ringed as 2cy bird orange C527R, today August 11 2002 in Tampere Finland (61.31N,23.43E). A bird with a dark iris and arm-span of 440 mm. 
The complete moult is well underway with most wing-coverts and the inner primaries moulted to second generation. The outermost primary P10 is still juvenile. P1-P7 are fully grown second generation flight-feathers and P8 is already reaching at the length of P6. The primary moult score is 41. The outer secondaries are replaced for second generation feathers: S1-S11 are new, from S12 inwards a small group of secondaries is missing and a few innermost secondaries are still juvenile.
The tertials and most of the wing-coverts are replaced for second generation feathers. The only wing-covert still to be replaced are the lesser coverts, of which feathers are still missing in the carpal edge. All scapulars have been replaced by second generation feathers, including the scapulars in the lowest row.

By August, the warm brown tones of the first moulted wing-coverts (inner greater coverts and median coverts) are faded to plain white, leaving a contrasting barred pattern on the wing-coverts. On average, 2cy argentatus is more contrastingly patterned than same aged 2cy argenteus, especially regarding the pattern on the central greater coverts. However, some argentatus are distinct "washed out" brown, showing the common vermiculated pattern of 2cy argenteus
The last moulted coverts are the central greater coverts and outer lesser coverts, replaced by mid-August. From mid-August onwards, 2cy argentatus start the partial autumn moult, starting again to drop the upper tertial and inner greater and median coverts.

In the table below, the primary moult scores of 2cy August argentatus in Finland can be read:

2cy argentatus in August, Tampere landfill, Finland, August 10 2002, 10:00-12:00 h.
  P5 new P6 new P7 new P8 new total old:
P9 old 1 8 8 - 17
P10 old - 15 42 2 59
no old - - 59 4 63
total new: 1 23 109 6 139
old primaries: m = 9.3, SD = 0.69, n = 139.
new primaries: m = 6.9, SD = 0.47, n = 139.