Anthropogenic sounds influence animal vocal behaviour, species distributions, and community assemblages. Natural sounds also have the potential to affect the behaviour and ecology of animals, but it is currently unknown if the effects of natural sounds match those of anthropogenic sounds. Here, we quantified and compared the effects of natural and anthropogenic sounds on avian song performance by calculating trade-off frontiers based on trill rate and bandwidth of 2 emberizid species. Chipping sparrows (Spizella passerina)...