Data from: 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 evaluated whether increasing the temporal
variability and amplitude of traffic noise increased deleterious effects
on sleep behavior in free-living great tits, and whether individuals
differed in the magnitude of responses.  We found that
traffic noise reduced sleep duration, proportion, and bout length, and
induced birds to exit nest boxes earlier in the
morning.  There was some support for a stronger effect
of more variable noise, and relative to lower amplitude noise, higher
amplitude noise resulted in less and more fragmented
sleep.  Effects of noise on sleep duration were stronger
in older adults, and substantial, repeatable variation existed in
individual responses. We demonstrate for the first time that anthropogenic
noise can have strong effects on sleep in free-living animals, which may
have cascading effects on waking behavior, physiology and
fitness.  Results suggest that reducing the amplitude of
traffic noise may be an effective mitigation strategy, and that
differences in individual sensitivity are important to consider when
evaluating effects of noise exposure.