Data from: Predicting the effect of urban noise on the active space of avian vocal signals

Urbanization changes the physical environment of non-human species, but also markedly changes their acoustic environment. Urban noise interferes with acoustic communication in a range of animals including birds, with potentially profound impacts on fitness. However, a mechanistic theory to predict which species of birds will be most affected by urban noise is lacking. We develop a mathematical model to predict the decrease in the active space of avian vocal signals when moving from quiet forest habitats to noisy urban habitats, and find that the magnitude of the decrease is largely a function of signal frequency. However, this relationship is not monotonic. A meta-regression of observed increases in the frequency of birdsong in urban noise supports the model's predictions for signals with frequencies between 1.5 and 4 kHz. Using the results of the meta-regression and the model described above, we show that the expected gain in active space following observed frequency shifts is up to 12%, and greatest for birds with signals at the lower end of this frequency range. Our generally-applicable model, along with three predictions regarding the behavioral and population-level responses of birds to urban noise, represents an important step towards a theory of acoustic communication in urban habitats.

城市化不仅改变了非人类物种的物理生境，同时也显著改变了它们的声学环境。城市噪声会干扰包括鸟类在内的多种动物的声学通讯，进而对其适合度（fitness）产生潜在的深远影响。然而，目前尚未存在能够预测哪些鸟类物种最易受城市噪声影响的机制性理论。本研究构建了一个数学模型，用以预测从安静森林生境转移至嘈杂城市生境时，鸟类鸣唱信号活动空间（active space）的缩减幅度，研究发现该缩减程度主要由信号频率决定。但该关联并非单调变化。针对城市噪声环境下鸟类鸣唱频率升高现象的元回归（meta-regression）分析结果，验证了本模型针对1.5~4 kHz频段信号的预测有效性。结合元回归分析结果与上述模型，本研究表明，基于观测到的鸣唱频率偏移所带来的活动空间预期增益可达12%，且该增益在鸣唱频率处于该频段下限的鸟类群体中最为显著。本研究所提出的普适性模型，连同三项关于鸟类对城市噪声的行为与种群水平响应的预测，为构建城市生境下的声学通讯理论迈出了关键一步。