Investigating social and environmental predictors of natal dispersal in a cooperative breeding bird

Natal dispersal is a crucial life history trait that affects both
individual fitness and population structure, yet drivers of variation in
dispersal probability and distance are difficult to study in wild
populations. In cooperatively breeding species, individuals typically
delay dispersal beyond their first breeding season and remain on the natal
territory as nonbreeders, which prolongs social dynamics that can affect
dispersal decisions. Using a 35-year data set covering almost 600
dispersal events in the cooperatively breeding Florida scrub-jay
(Aphelocoma coerulescens), we examined the environmental and social
parameters that predict dispersal probability over time and distance. In
both sexes, dispersal probability increased with age, which in turn was
negatively correlated with dispersal distance. In males, individuals
occupying low quality natal territories and living with a stepfather had
an increased probability of dispersal. Older and more dominant males were
more likely to inherit their natal territory. In females, which generally
disperse earlier and farther than males, socially subordinate jays
dispersed farther than dominant ones. Overall, jays that delayed dispersal
the longest were more likely to attain breeding status near their natal
territory, which was previously found to be associated with increased
survival and lifetime fitness. Our results suggest that social dynamics
and environmental factors on the natal territory affect delayed dispersal
patterns differently for the two sexes in this cooperative breeder.