second calendar year: September 

By September all 2cy LBBG are moulting primaries, secondaries and many also moult coverts.

Moult in the remiges:

Only a small minority of 2cy LBBG still have old juvenile primaries left in the wing (and this is the last p10, see e.g. picture 2), but many have shed all the juvenile primaries and grow new second generation primaries. Compared to (fresh) juvenile primaries, the top of second generation primaries is rounded. The average moult stage by early September is just above 40, with p7 full-grown, while p8 and p9 are growing. At the end of the month the primary score is over 45, with p7 or p8 full-grown and p9 and p10 growing. 

On average, the outer secondaries (from S1 inwards) are full-grown by September, but in the inner secondaries have been shed. By mid-September, birds can be found with old and new secondaries and gaps of shed feathers. By the end of the month, in most individuals the secondaries have been renewed completely and can be recognized as such by the fresh white tip.

Moult in the rectrices:

On average the tail has completely been renewed into second generation. Typically, the contrast is obvious: the base commonly shoes vermiculation on the edge of a broad black tail-band and a small white fringe at the tips. In some individuals, the tail-feathers are abraded already with the tips worn away. Probably, these are the birds that had replaced the complete tail earlier in the season (in spring). The upper-tail coverts normally show broad brown bars.

Tertials:

The tertials are missing or have been replaced by second generation feathers. The upper two tertials normally are the last to be moulted. The new tertials have an extensive brown-black centre, a white bar at the tip and a sub-terminal anchor pattern at the tip. Sometimes a (single central) tertial may appear grey-centred with an arrow-head; a faint brown pattern along the fringe and a faded white tip (see for instance image 7). Probably, these feathers are already 3^rd generation feathers and have replaced tertials which were included in last autumn's moult.

Coverts:
In all the wing covert bars, active moult may be in progress. In several individuals moult to second generation greater coverts and outer lesser coverts have to be finished as late as the end of September. Normally the median coverts are the first to be moulted, early in the season. By September however, it's still possible to find 2cy LBBG which have shed the median coverts, growing new feathers in. These birds are moulting the median coverts again into 3^rd generation feathers. In pattern they resemble the anchor or barred patterned 2^nd generation feathers (see image 7). Other individuals show the pattern as seen in presumed intermedius LBBGs: plain brown-grey coverts with a pronounced black wedge at the cente (see e.g. image 5 and image 6).

Under-parts and head:

These feather groups have been renewed by neat feathers, with fine streaks on the ear coverts and neat vermiculate bars on the flanks (see e.g. image 1). 

Tables

LBBG 2cy J6PH September 16 2007, IJmuiden, the Netherlands. 2cy & 4cy.