16 17 18 19 20 21 22 Increasing scientific evidence shows that anthropogenic noise can impact behavioral, 23 demographic and community-level processes across a range of taxapresenting a serious 24 2 conservation challenge. Given the direct link between antipredator behavior and fitness, it is 25 important to explore the impacts of noise on vigilance and flight. To do this, we conducted 26 playback experiments to to test whether noise distracts black-tailed prairie dogs from attending to 27 an

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... proaching predator or whether increased noise exposure led to heightened vigilance and 28 responsiveness. Contrary to the 'distracted prey hypothesis', prairie dogs responded at greater 29 distances to the approaching human "predator" and took flight more rapidly in noise than during 30 the quieter control. Greater vigilance is likely to be a function of increased perceived threat as 31 opposed to distraction, enabling the prairie dogs to evade predators sooner. However, there are 32 energetic and potential fitness costs associated with heightened vigilance and flight, including the 33 loss of foraging opportunities. Interestingly the reactiveness of the prairie dogs to the 34 approaching observer increased over the course of the study, but there was no apparent change in 35 their responses to other humans using the natural area. This may reflect their impressive cognitive 36 abilities that enable discrimination between different predatorseven human observers. Our 37 findings emphasize that the complex biological responses to anthropogenic noise are dependent 38 upon the biology of the species as well as the acoustic characteristics of the noise source. 39 40