Variable and consistent traffic noise negatively affect the sleep behavior of a free-living songbird

Anthropogenic noise is an ubiquitous disturbance factor, which, owing to the extensive nature of transportation networks, and ability of sound waves to penetrate distances, has wide-reaching impacts on biological communities.  Research effort on biological effects of anthropogenic noise is extensive, but has focused on waking behavior, and to our knowledge, no published experimental study exists on how noise affects sleep in free-living animals.  Sleep plays vital functions in processes such as cellular repair and memory consolidation.  Thus, understanding the potential for noise to disrupt sleep is a critical research objective.  Whether different noise regimes exert distinct effects on behavior also remains poorly understood, as does intraspecific variation in noise sensitivity.  To address these knowledge gaps, we used a repeated-measures field experiment involving broad-casting traffic noise recordings at great tit (Parus major) nest boxes over a series of consecutive nights.  We ev...