This paper presents some adaptations to usual primary moult scores in terns. It is proposed to score old ‘arrested’ moult series separately, to facilitate the analysis of moult in the breeding period more effectively. To do this in a comparable manner, it is proposed to record moult scores for active series (after breeding) as A = new first series. B = new second series and C is new third series. For old (arrested) primaries this can be expanded to: E = old first series, F = old second series and G = old third series. Some examples for Black Tern are presented for the whole annual cycle.