Backhouse Fiona, Dalziell Anastasia H, Magrath Robert D, Rice Aaron N, Crisologo Taylor L, Welbergen Justin A
The Hawkesbury Institute for the Environment Western Sydney University Richmond NSW Australia.
Centre for Sustainable Ecosystem Solutions School of Earth, Atmospheric and Life Sciences University of Wollongong Wollongong NSW Australia.
Ecol Evol. 2021 Feb 14;11(6):2701-2716. doi: 10.1002/ece3.7225. eCollection 2021 Mar.
Geographic variation in bird song has received much attention in evolutionary studies, yet few consider components within songs that may be subject to different constraints and follow different evolutionary trajectories. Here, we quantify patterns of geographic variation in the socially transmitted "whistle" song of Albert's lyrebirds (), an oscine passerine renowned for its remarkable vocal abilities. Albert's lyrebirds are confined to narrow stretches of suitable habitat in Australia, allowing us to map likely paths of cultural transmission using a species distribution model and least cost paths. We use quantitative methods to divide the songs into three components present in all study populations: the introductory elements, the song body, and the final element. We compare geographic separation between populations with variation in these components as well as the full song. All populations were distinguishable by song, and songs varied according to the geographic distance between populations. However, within songs, only the introductory elements and song body could be used to distinguish among populations. The song body and final element changed with distance, but the introductory elements varied independently of geographic separation. These differing geographic patterns of within-song variation are unexpected, given that the whistle song components are always produced in the same sequence and may be perceived as a temporally discrete unit. Knowledge of such spatial patterns of within-song variation enables further work to determine possible selective pressures and constraints acting on each song component and provides spatially explicit targets for preserving cultural diversity. As such, our study highlights the importance for science and conservation of investigating spatial patterns within seemingly discrete behavioral traits at multiple levels of organization.
鸟类歌声的地理变异在进化研究中备受关注，但很少有人考虑歌声中可能受到不同限制并遵循不同进化轨迹的组成部分。在这里，我们量化了阿尔伯特琴鸟（一种以其卓越发声能力而闻名的鸣禽雀形目鸟类）通过社会传播的“口哨”歌声的地理变异模式。阿尔伯特琴鸟局限于澳大利亚狭窄的适宜栖息地范围内，这使我们能够利用物种分布模型和成本最低路径来绘制可能的文化传播路径。我们使用定量方法将歌声分为所有研究种群中都存在的三个组成部分：起始元素、歌体和结尾元素。我们将种群之间的地理距离差异与这些组成部分以及整首歌的差异进行比较。所有种群都可以通过歌声区分开来，并且歌声会根据种群之间的地理距离而变化。然而，在歌声内部，只有起始元素和歌体可用于区分不同种群。歌体和结尾元素随距离变化，但起始元素的变化与地理距离无关。鉴于口哨歌声的组成部分总是按相同顺序产生，并且可能被视为一个时间上离散的单元，歌曲内部变异的这些不同地理模式是出乎意料的。了解歌曲内部变异的这种空间模式能够进一步开展工作，以确定作用于每个歌曲组成部分的可能选择压力和限制，并为保护文化多样性提供空间明确的目标。因此，我们的研究强调了在多个组织层面研究看似离散的行为特征内部空间模式对于科学和保护工作的重要性。
