Photo 1: LBBG sub-adult (4cy?), June 16 2001, Dintelhaven
Maasvlakte, the Netherlands.
Probably a 4cy bird with still some dark markings in the tail feathers. The outer primaries
show no white tips, but these may have worn away (although the primaries
are not extremely abraded and just slightly faded, brownish). There is a small mirror
on p10; the borders of the white mirror just reach the edge of the
primary. Normally, this white patch borders the p10 edge over quite a distance
in full adult plumage.
When the wing is raised (bottom picture), note the old primary coverts with obvious white
tips.
Otherwise, in a resting position, it very much resembles an adult LBBG.