Anthropogenic environments expose organisms to an array of novel stressors such as light, noise, and chemical pollution. These disturbance factors may interfere with adaptive behaviors and activate stress responses, with deleterious fitness effects. Sleep is a fundamental component of animals’ daily life and sleep deprivation has well-documented deleterious effects on health status. Thus, a primary aim of this project was elucidating whether sleep disruption occurs as a consequence of exposure to light and noise pollution, using a model species, the great tit (Parus major). In addition, I explored how noise, light and chemical pollution affect other aspects of behavior and physiology in these songbirds, including underexplored effects on developing nestlings (e.g. telomere dynamics), and effects on sexual coloration and parental behavior in adults. Finally, I strove to elucidate intraspecific differences in sensitivity to disturbance. Animal personalities, or individually-repeatable differences in behavior, have now been widely documented and may affect sensitivity to disturbance, especially via hormonal correlates.
This project has yielded valuable results, which advance the state-of-the-art. First, results suggest that exposure to ALAN and anthropogenic noise have deleterious effects on developing organisms, providing motivation for mitigation policies. In addition, noise exposure did not affect all nestlings equivalently, suggesting that identifying individual traits that affect stress sensitivity is important to detecting effects of human disturbance. Second, research on adults demonstrated that sexually-selected, carotenoid-based coloration is reduced in birds breeding closer to roads and with higher feather metal concentrations, with important implications for sexual signaling dynamics in anthropogenic landscapes. In addition, the nature of the noise regime, personality type and sex interacted to predict effects of noise exposure on nestling provisioning behavior, again suggesting intraspecific variation in sensitivity to disturbance. Finally, despite significant individual level variation in the effect of ALAN on sleep, effects were not dependent on personality type, as characterized by novel environment exploration behavior. A study involving the effect of constant and variable anthropogenic noise regimes on sleep behavior is currently in the analysis stage.
