Plumage coloration and personality in early life: sexual differences in signalling

Abstract

Several studies have shown that melanin-based traits play a crucial role in social contexts as they are associated with dominance, personality and social behaviour. However, most of these studies have focused on adults, and the role of these traits in juveniles has rarely been explored. Here, we explore the association between two melanin-based traits and nestling personality in Common Kestrels Falco tinnunculus. Our results show that female nestlings with blacker plumages displayed bolder personalities, providing evidence of sex-dependent phenotypic integration of these two traits in males and females. We consider that this differential integration may arise from different selection pressures acting on males and females on plumage coloration during adulthood and that nestling coloration can act as a status signal within the juvenile age-class.