A Bat activity declines with increasing sound levels. B Bat activity declines with increasing frequency of the acoustic environment. C Phylogenetically-informed trait analyses reveal that higher frequency echolocators are more likely to avoid high sound-level environments (n = 12 species). D Foraging modality for flexible bat species appear to shift from passive listening to aerial-hawking with variation in background sound level and frequency. Blue lines denote predicted declines in bat detections at artificial prey sounds speakers with increased sound level where the top and bottom lines reflect median background frequencies at 10 and 8 kHz, respectively. Red lines denote the predicted increase in bat detections at robotic fluttering insects with higher noise levels at 8 kHz (top line) and 6 kHz (bottom line). For all plots, points represent raw data (species estimates for C), error bars represent standard errors (C only), the plotted lines (estimated conditional means) and shaded regions (95% confidence intervals) represent predicted values of the response variable over the range of the variable on the x axis, given constant mean values of all other variables in the model (except in D).