Personal and neighbourhood information are drivers in breeding dispersal departure decisions of a territorial migratory songbird

Mechanisms driving breeding dispersal are complex but are of high interest because dispersal strongly links individual fitness to population dynamics. We examine the relative importance of personal information, neighbourhood effects and structural habitat characteristics in determining an individual's propensity for breeding dispersal. We attempted to identify relevant cues for breeding dispersal of a North American territorial migratory bird species, the Black‐capped Vireo Vireo atricapilla . We colour‐marked and radiotagged males in Southwestern Oklahoma, and used a conditional inference tree analysis to evaluate 11 variables that individuals could use as predictors of dispersal. We used the correlation between arrival date and habitat structure to determine habitat preference. Breeding dispersal propensity among Black‐capped Vireos depended mostly on their personal breeding experience, but also on reproductive information gleaned from their neighbours. Older and younger age‐classes that reproduced successfully did not disperse, but younger age‐class individuals that failed to reproduce were more likely to disperse than older individuals within the breeding season. Dispersal events among young males were significantly related to the proportion of their neighbours that successfully reproduced, with more dispersal from neighbourhoods of fewer, less successful neighbours. Vegetation structure within a territory was not identified as a significant cue. However, in this Oklahoma population, Black‐capped Vireos of different ages were spatially segregated into habitats of differing structure, which may further influence neighbourhood quality and the degree to which age‐group participates in breeding dispersal. Our results indicate localized, neighbourhood effects are important to breeding dispersal, which has implications for the establishment of new populations or a stabilization of a population within a metapopulation. Future studies focused on the spatio‐temporal aspects of breeding dispersal would be valuable. Especially useful for future research will be studies of the search behaviours of dispersing individuals and processes involved in selecting new habitat after leaving their initial territory.