Photo 11: LBBG sub-adult, April 16 2001, ECT centrale Maasvlakte, the Netherlands.

Normally in 4cy, the bill has a distinct black bill-band, but in this LBBG only a faint black mark on the upper mandible is visible.
In the coverts, many immature brown feathers can be seen: almost all the greater coverts still have to be moulted. Tertials #1 and 2 are adult-like grey with a large white tip, but #3 to 6 show a brownish centre.
Compared to full adult LBBG, the tips of the primaries are small.
In the bottom picture, the bird standing left in the background is an adult ringed LL1, born summer 1993.