Photo 10: LBBG sub-adult?, September 2 2001, Brouwersdam, the Netherlands.

Adult or sub-adult? That's the question. It may be very difficult to distinguish between some 4cy, 5cy or older LBBG. Sometimes the primary coverts may give a clue, because these feathers are often slightly browner and may show white tips in 4cy birds, where they are plain grey (or grey with a black centre) in adults. It seems, sub-adult LBBG may show a stronger brown hue on old feathers and also these feathers are on average more abraded as old adult feathers.

P1 to p5 are new, with p5 just shorter than p4. From p3 onwards, black sub-terminal markings are visible and at p5 these markings form a complete sub-terminal band.