Typical second generation tail for 2cy Yellow-legged Gull in autumn, where the black tail band and variegated pattern on the basal half of the feathers contrast strong with the white upper-tail coverts (see bottom picture).

P10 is almost fully grown by mid-September and has to grow just an inch or so, resulting in a primary moult score (PMS) of 49. See Gull Topography for explanation of PMS.

The upper two tertials are missing (one new tip is just visible), the lower four are old (probably second generation) feathers.

The exact generation of tertials is difficult to proof when dealing with unringed birds, which have not been followed over the last two years. As can be seen in several 1cy sections, many michahellis include upper tertials in the post-juvenile (first pre-basic) moult, so the moult in 2cy autumn birds may result in new upper tertials of fourth generation.
The lower tertials are still old, either second or third generation feathers. As can be seen in the 1cy sections, not many birds include all tertials in the post-juvenile moult, so the majority of 2cy michahellis have second generation lower tertials (only moulted once during the complete moult last summer).

The innermost three greater coverts have been shed and new feathers are growing. The central median coverts are currently growing and the inner four have been replaced very recently, still showing a greyish base in the centres and very fresh fringes. A few lesser coverts have been shed but the majority is old and the fringes show wear.

In the scapulars, new feathers (note the white fringe) may still show an anchor pattern or at least a sub-terminal band and pronounced shaft streak and resemble second generation scapulars in this respect. Note the almost completely dark bill and the delicate streaks on the head.