Photo  3: adult LBBG, July 7 2001, IJmuiden, the Netherlands. 

A nice example of a bird showing a distinction between primary 5 and 6, although they were replaced in the same period. Often, p5 is hidden by the tertials and therefore the tip of this primary may look much fresher than the tip of the next, p6. However, there is no arrested moult, as in arrested moult it's often the complete feather that looks more bleached, with a brown hue. To interpret difference in wear (to be certain about arrested moult) between p5 and p6 may be very hard, while a division between two different generations of primaries is pretty easy to recognize between any other two primaries.