Effects of Artificial Light at Night on Avian Provisioning, Corticosterone, and Reproductive Success

Synopsis Artificial light at night (hereafter “ALAN”) affects 88% of the land area in Europe and almost half USA, with even rural areas exposed to lights from agricultural industrial buildings. To date, there have been few studies that assess impacts ALAN on both wildlife behavior physiology. However, may alter energy expenditure and/or stress physiology during breeding period, potentially reducing reproductive success resulting conservation implications. Here, we experimentally adult female nestling tree swallows (Tachycineta bicolor) ALAN. We then measured effects compared control conditions parental (provisioning rate), (corticosterone levels), (likelihood all eggs hatching nestlings fledging per nest). Our results showed ALAN-exposed females provisioned their lower rates than females. Although relatively weak, our also suggested had reduced baseline increased stress-induced corticosterone nestlings. greater negative feedback circulating corticosterone. found no support for prediction would reduce body condition. Finally, some a effect likelihood hatched given nest, but not fledged. Therefore, while it is possible behavioral physiological changes here result long-term consequences, suggest direct exposure alone substantially large or swallows. Exposure regimes free-living birds, such as combination anthropogenic disturbances (i.e., noise pollution) indirect due alterations food availability), produce different those here.