Cities differ from non-urban environments by the intensity, scale, and extent of anthropogenic pressures, which can drive the occurrence, physiology, and behavior of the organisms thriving in these settings. Traits as green cover often predict the occurrence patterns of bird species in urban areas. Yet, anthropogenic noise and artificial light at night (ALAN) could also limit the presence and disrupt the behavior of birds. However, there is still a dearth of knowledge about the influence of urbanization through noise and light pollution on nocturnal bird species ecology. In this study, we assessed the role of green cover, noise, and light pollution on the occurrence and vocal activity of the Mottled Owl (Ciccaba virgata) in the city of Xalapa (Mexico). We obtained soundscape recordings in 61 independent sites scattered across the city of Xalapa using autonomous recording units. We performed a semi-automated acoustic analysis of the recordings, corroborating all Mottled Owl vocalizations. We calculated two measures of anthropogenic noise at each study site: daily noise (during 24 h) and masking noise (mean noise amplitude at night per site that could mask the owl’s vocalizations). We further performed generalized linear models to relate green cover, ALAN, daily noise, and masking noise in relation to the owl’s occurrence (i.e., detected, undetected). We also ran linear models to assess relationships among the beginning and ending of vocal activity with ALAN, and with the anthropogenic and masking noise levels at the moment of which vocalizations were emitted. Finally, we explored variations of the vocal activity of the Mottled Owl measured as vocalization rate across time. The presence of Mottled Owls increased with the size of green cover and decreased with increases in both artificial light at night and noise levels. At the temporal scale, green cover was positively related with the ending of the owl’s vocal activity, while daily noise and ALAN levels were not related to the timing and vocal output (i.e., number of vocalizations). Furthermore, the Mottled Owl showed a marked peak of vocal activity before dawn than after dusk. Although anthropogenic noise levels varied significantly across the assessed time, we did not find an association between high vocal output during time periods with lower noise levels. Spatially, green cover area was positively related with the presence of the Mottled Owl in Xalapa, while high noise and light pollution were related to its absence. At a temporal scale, daily noise and ALAN levels were not related with the timing and vocal output. This suggests that instead of environmental factors, behavioral contexts such as territoriality and mate interactions could drive the vocal activity of the Mottled Owl. Further studies need to incorporate a wider seasonal scale in order to explore the variation of different vocalizations of this species in relation to environmental and biological factors.

中文翻译：

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城市夜生活：热带猫头鹰发生和发声活动的驱动因素

城市与非城市环境的不同之处在于人为压力的强度，规模和程度，这可以驱动在这些环境中繁衍的生物的发生，生理和行为。绿色覆盖的特征通常可以预测城市地区鸟类的发生方式。但是，人为的噪音和夜间人造光（ALAN）也可能会限制鸟类的存在并破坏鸟类的行为。但是，关于噪声和光污染引起的城市化对夜间鸟类物种生态学的影响的知识仍然匮乏。在这项研究中，我们评估了绿色覆盖，噪声和光污染对墨西哥Xalapa市斑驳猫头鹰（Ciccaba virgata）发生和发声活动的作用。我们使用自治的录音装置在遍布Xalapa的61个独立站点中获得了音景录音。我们对录音进行了半自动声学分析，证实了所有“斑驳的猫头鹰”的发声。我们计算了每个研究地点的两种人为噪声度量：每日噪声（24小时内）和掩蔽噪声（每个站点夜间的平均噪声振幅，可能掩盖猫头鹰的发声）。我们进一步执行了广义线性模型，以将绿色覆盖率，ALAN，日常噪声和掩蔽噪声与猫头鹰的发生（即，已发现，未发现）相关联。我们还运行了线性模型，以评估语音活动的开始和结束与ALAN之间的关系，以及与发声时的人为和掩蔽噪音水平之间的关系。最后，我们探索了斑驳猫头鹰的发声活动随时间的发声率的变化。斑驳猫头鹰的出现随着绿色覆盖物的大小而增加，并且随着夜间的人造光和噪声水平的增加而减少。在时间尺度上，绿色掩盖与猫头鹰的声活动的结束呈正相关，而日常噪声和ALAN的水平与时间和声音输出（即发声次数）无关。此外，斑驳的猫头鹰在黎明之前比黄昏之后显示出明显的声音活动高峰。尽管人为的噪音水平在整个评估时间内变化很大，但我们并未发现在较低的噪音水平期间高人声输出之间存在关联。在空间上，绿色覆盖面积与Xalapa中斑驳猫头鹰的存在呈正相关，而高噪音和光污染与其缺乏有关。在时间尺度上，日常噪声和ALAN水平与时间和声音输出无关。这表明，代替环境因素，诸如上下文和伴侣互动等行为环境可以驱动斑驳猫头鹰的发声活动。进一步的研究需要纳入更广泛的季节尺度，以探索该物种不同发声与环境和生物因素有关的变化。