PDF(Pubmed)
Abstract：
Predator-prey arms races have led to the evolution of finely tuned disguise strategies. While the theoretical benefits of predator camouflage are well established, no study has yet been able to quantify its consequences for hunting success in natural conditions. We used high-resolution movement data to quantify how barn owls (Tyto alba) conceal their approach when using a sit-and-wait strategy. We hypothesized that hunting barn owls would modulate their landing force, potentially reducing noise levels in the vicinity of prey. Analysing 87,957 landings by 163 individuals equipped with GPS tags and accelerometers, we show that barn owls reduce their landing force as they approach their prey, and that landing force predicts the success of the following hunting attempt. Landing force also varied with the substrate, being lowest on man-made poles in field boundaries. The physical environment, therefore, affects the capacity for sound camouflage, providing an unexpected link between predator-prey interactions and land use. Finally, hunting strike forces in barn owls were the highest recorded in any bird, relative to body mass, highlighting the range of selective pressures that act on landings and the capacity of these predators to modulate their landing force. Overall, our results provide the first measurements of landing force in a wild setting, revealing a new form of motion-induced sound camouflage and its link to hunting success.
摘要：
捕食者-猎物的军备竞赛导致了精心调整的伪装策略的演变。虽然捕食者伪装的理论好处是公认的，还没有研究能够量化其在自然条件下狩猎成功的后果。我们使用高分辨率的运动数据来量化谷仓猫头鹰（Tytoalba）在使用坐着等待策略时如何隐藏其方法。我们假设猎杀谷仓猫头鹰会调节它们的着陆力，有可能降低猎物附近的噪音水平。分析了163名配备GPS标签和加速度计的个人的87,957次着陆，我们表明谷仓猫头鹰在接近猎物时降低了着陆力，登陆力量预测了接下来的狩猎尝试的成功。着陆力也随基板而变化，在野外边界的人造电线杆上最低。物理环境,因此,影响声音伪装的能力，在捕食者-猎物相互作用和土地利用之间提供了意想不到的联系。最后,谷仓猫头鹰的猎杀力量是所有鸟类中最高的，相对于体重，强调作用于着陆的选择性压力的范围以及这些捕食者调节其着陆力的能力。总的来说,我们的结果提供了野外着陆力的首次测量，揭示了一种新形式的运动诱发的声音伪装及其与狩猎成功的联系。
