Loyal and regular readers, both of you, will recall a short time ago I was out and about with BTO Birdtrack bigwig Nick Moran and we were chasing down Black Grouse and asking questions about the ageing of said beasts.
Nick with all the resources of the BTO at hand has had some interesting comments from John Calladine a Senior Research Ecologist with the BTO in Scotland who said:
If these are recent photos (Feb/March), I'd have thought that adults should be good fresh plumage. Without checking the literature, they (or at least the males) have a heavy moult in late summer/autumn and become very shabby but are in full plumage by mid-winter. Given the markedly duller coverts and broader pale margins to the flight feathers I'd have thought the bird on the wall was a 1st year bird (hatched last year). Absence (or near absence) of a red wattle suggests that too - unless that's just an artefact of the photo.
So perhaps we got it right on the day 2 adults and 4 2nd-calendar year males making up the six we saw.