Figure 1.

The reproductive success of males of different behavioural status. (a) Sampled chicks were overwhelmingly sired by alphas. (b) Seven of twelve males that sired chicks while neither alpha nor beta were identified behaviourally as alpha in the following breeding season, and this tended to occur in the early years of the study, suggesting that incomplete behavioural sampling of male display areas may have occurred in these years or that males gained paternity as they transitioned between status classes. Solid bars, sire not alpha in next year; hatched bars, sire alpha in next year.