A path analysis disentangling determinants of natal dispersal in a cooperatively breeding bird.

Abstract

Delayed offspring dispersal, the prolonged residence in the natal territory after reaching independence and before dispersing to breed elsewhere, is an important aspect of the evolution of cooperative breeding. By applying a path analysis approach to the long-term Seychelles warbler (Acrocephalus sechellensis) dataset, we studied whether and how delayed dispersal is affected by territory quality, the presence of helpers and non-helping subordinates, maternal breeding status, age and fecundity, and offspring sex ratio. We found that offspring are more likely to disperse when their genetic mothers are co-breeders, helpers are absent, and territory quality is high, highlighting that a complex interplay of ecological and social factors shapes dispersal decisions. In contrast to earlier findings, our analysis does not support the idea that the offspring sex ratio is affected by territory quality and helper presence. Collectively, this study underscores the importance of considering proximate factors in understanding cooperative breeding dynamics, and it shows that path analyses offer valuable insights into dissecting the intricate relationships influencing dispersal in wild populations.