Potential mechanisms that influence first-breeding site selection and quality

In cooperatively breeding species that delay dispersal, the proximate mechanism that drives variation in dispersal timing and subsequent selection is often unclear. We studied potential mechanisms that drive differences in first-time territory acquisition in the cooperative breeding, permanently territorial corvid, the Florida Scrub-Jay (Aphelocoma coerulescens, FSJ). A habitat specialist confined to fire-maintained, early successional oak scrub, FSJs experience increased fitness in high quality habitat in terms of recent fire history and amount of oak scrub available in the territory. We hypothesized that competition for the highest quality habitats helps explain the observed variation in timing of territory acquisition and in territory quality acquired by novice breeders. We examined three potential mechanisms – social dominance, duration of delay in dispersing, and mode of territory acquisition – that could affect territory acquisition. The hypotheses predicted that 1) more dominant and 2) older individuals disperse into higher quality habitat, and 3) certain acquisition modes are associated with habitat quality. We also predicted that males and females would differ. Using long-term data from Archbold Biological Station, FL, we looked at 439 individuals that became breeders between 1980 and 2015. We used linear mixed models to test for fixed and random effects. The results of the models showed that while dominance was not a significant predictor, the predictors sex, age at first breeding, and territory acquisition type were associated with differences in territory quality overall. This suggests that various mechanisms influence individual habitat selection, contributing to the variation observed.