Urbanisation has been shown to influence many aspects of animal vocal communication. Much attention has been paid to anthropogenic noise, which is often described as one of the most challenging disturbances for urban dwellers. While a large body of literature describes associations between vocal behavior of avian populations and background noise level, most of these studies were conducted on species with relatively simple songs and small repertoire sizes. This study focuses on the song thrush, Turdus philomelos, a common Eurasian songbird with a complex singing style and large syllable repertoire. Our objective was to determine whether frequency, repertoire and temporal organisation of song parameters vary between birds inhabiting urban and adjacent forest habitats in which ambient noise levels differ. Songs of urban males were found to be more complex than in conspecifics from natural forest populations. Urban dwellers possessed greater syllable repertoires and repeated syllable sequences more often. In addition, they used a smaller proportion of whistles and a higher proportion of twitter syllables when singing compared to the nonurban males. Moreover, we found significant differences in the minimum and peak frequency of the whistle syllable between studied populations. These findings may be an example of adaptation of acoustic communication in noisy urban environments, but we also discuss other possible explanations. We emphasize the need for further investigation into the relationships between birdsong and habitat characteristics, male quality, population density and ambient noise level in populations occupying urban and nonurban habitats.

中文翻译：

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具有丰富曲目的鸣禽中与栖息地相关的歌曲结构和复杂性差异

事实证明，城市化会影响动物声音交流的许多方面。人为噪声引起了人们的极大关注，人为噪声通常被描述为城市居民最具挑战性的干扰之一。虽然大量文献描述了禽类种群的声音行为与背景噪声水平之间的关联，但大多数研究是针对歌曲相对简单且曲目数量较小的物种进行的。这项研究的重点是鹅口疮，Turdus philomelos，这是一种常见的欧亚鸣禽，具有复杂的歌唱风格和较大的音节。我们的目标是确定居住在城市和邻近森林栖息地（环境噪声水平有所不同）的鸟类之间歌曲参数的频率，曲目和时间组织是否有所不同。发现城市男性的歌曲比来自天然森林种群的同名歌曲更为复杂。城市居民拥有更多的音节曲目，并且更频繁地重复音节序列。此外，与非城市男性相比，他们唱歌时使用的口哨声比例较小，而twitter音节的比例较高。此外，我们发现研究人群之间的最低和最高的口哨音节频率差异。这些发现可能是在嘈杂的城市环境中适应声学通信的一个例子，但我们还将讨论其他可能的解释。我们强调有必要进一步调查鸟类和栖息地特征，雄性质量，种群密度和环境噪声水平在城市和非城市栖息地人口中的关系。