Trait mediated effects of anthropogenic noise on bird behavior and fitness

Birds are considered especially vulnerable to anthropogenic noise because
of their reliance on acoustic information. Single-species research shows
that noise can impact different aspects of bird behavior and consequently
reduce their fitness. However, we have a limited understanding of how
ecological and life-history traits mediate responses to anthropogenic
noise across species. We performed a meta-analysis to quantify noise
impacts on bird behaviors (communication, cognition, aggression, risk,
foraging, and habitat use) and fitness-related responses (growth,
physiology, and reproduction), and how bird traits, such as nesting and
habitat type, mediated those responses. Using 944 effect sizes from 160
bird species across 6 continents, we found that anthropogenic noise
significantly affected various behaviors as well as physiology and has
strong negative effects on reproductive responses. We also found that
anthropogenic noise had stronger negative effects on bird reproduction for
species that nest nearer to the ground, while growth and physiological
responses were stronger for species that nested in open rather than cavity
nests and those living in deciduous forests, respectively. Our results
highlight the characteristics of those birds most vulnerable to noise
pollution and inform how conservation actions can best reduce the impacts
of human-made noise in those species’ habitats.