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
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
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.