Cities do not only represent noisy systems, but also limit acoustic communication given the complex array of artificial structures through which signals can be trapped or obscured. In this study we performed a field experiment to evaluate the loss of energy of a standardized acoustic emission (generated with notes and a call of the Clay-colored Thrush – Turdus grayi). For this, we emitted the acoustic signal and recovered it at increasing radial distances from 26 fixed emission points (i.e., 10 m, 20 m, 40 m, 80 m, 120 m, 160 m) located across the city of Xalapa (Mexico). Our results show that the emitted signal was not recorded beyond 80 m from the emission point. The number and height of the assessed physical obstacles between the emitted signal and the receiving equipment showed to drive our main result, with built elements representing a major barrier than vegetation ones in terms of the recovered energy of the emitted signal. Interestingly, we found that, for both types of physical obstacles, a height of ~7 m was a common threshold influencing the recovered energy of the emitted signal.

城市不仅代表着嘈杂的系统，而且由于人造结构的复杂阵列可以限制信号的传播，而且限制了声音的传播。在这项研究中，我们进行了现场实验，以评估标准声发射的能量损失（产生时带有音符，并发出黏土色鹅口疮–  Turdus grayi）。为此，我们发出了声信号，并从位于墨西哥Xalapa市的26个固定发射点（即10 m，20 m，40 m，80 m，120 m，160 m）沿径向距离增加的距离处恢复了声信号。我们的结果表明，在距发射点80 m处未记录发射信号。在发射信号和接收设备之间评估的物理障碍物的数量和高度表明，这将驱动我们的主要结果，就发射信号的回收能量而言，建筑元素代表的障碍比植被障碍要大。有趣的是，我们发现，对于两种类型的物理障碍物，〜7 m的高度都是影响发射信号恢复能量的常见阈值。