(2 images) Herring Gull HT-230.904 2cy (argentatus), July 15 2003, Tampere, Finland (61.31N, 23.43E).

A 2cy argentatus, ringed HT-230.904. The complete moult is well underway with most wing-coverts and the inner primaries moulted to second generation. Primary P7 has been dropped and P8-P10 are still juvenile. P1-P5 are fully grown second generation flight-feathers. The central tail-feathers are dropped, but the outer feathers are still present.
Some tertials and most of the wing-coverts are replaced for second generation feathers. The central greater coverts are missing/growing. The new greater coverts grown in descendant order, from the outer-wing inwards, as is the common sequence. The gap in the median covert row is just closed, with the two last replaced feathers still buffish tinged. Most juvenile wing-coverts can be found in the upper row of lesser coverts.

By July, the warm brown tones of the first moulted second generation feathers (inner greater coverts and inner 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 tables below, the primary moult scores of 2cy July argentatus in Finland can be read: