Ontogeny of social skills: Social complexity improves mating and competitive strategies in male brown-headed cowbirds

Social individuals require a suite of skills to outcompete groupmates and gain reproductive advantage. Recently we showed that adult male cowbirds (. Molothrus ater) exposed to enhanced social-learning opportunities (living in 'dynamic' social conditions) became more reproductively successful than males living in 'stable' conditions (. White et al. 2010a, . Animal Behaviour, . 79, 385-390). The experiment left open important questions about how subjects turned the experiences they gained in the dynamic condition into a reproductive advantage. Here, 1. year later, we examined the within-individual plasticity of the effect by exposing some of the same subjects to opposite social conditions, followed by another opportunity to measure their relative reproductive success. Again, dynamic-condition birds outcompeted stable-condition birds, reversing individuals' performances from the year before. We investigated the constituents of the dynamic-condition birds' advantage, and found that they succeeded by using aggression to increase dominance rank, and by focusing courtship singing on forming consortships with particular females. Stable-condition birds adhered to no discernible strategy. This work affirms that adult experience can modify reproductive success, and suggests a mechanism for that modification: individuals that experience a wider array of social environments may improve their 'behavioural control', the ability to modulate behaviour to suit the competitive context. Natural selection may act on groups of traits that facilitate the development of behavioural control, including faculties for expressing or inhibiting behaviours and traits that regulate individuals' exposure and attention to social experience.