Transcontinental latitudinal variation in song performance and complexity in House Wrens (Troglodytes aedon)

There is growing interest in latitudinal effects on animal behavior and life-history. One recent focus is on birdsong which is hypothesized to be more elaborated or complex in the north temperate zone compared to the tropics. Current evidence is mixed and based on cross-species comparisons, or single species with restricted distributions. We circumvent these limitations using a transcontinental sample of 358 songs from House Wrens (Troglodytes aedon) at 281 locations spanning more than 100O of latitude (52 O N - 55 O S) across the Americas. We found a significant latitudinal gradient in several basic elements of song performance and complexity between north temperate and tropical populations. Further, we document convergence in song patterns between populations at higher latitudes in the northern and southern hemispheres. Effects were strongest for the number of elements in a song, and the rate of element production, both increasing towards the poles, with similar but weaker effects for...

学界对纬度对动物行为与生活史的影响日益关注。近期的研究焦点之一聚焦于鸟鸣（birdsong）：有假说提出，相较于热带地区，北温带的鸟鸣更为繁复复杂。现有相关证据尚无定论，且多基于跨物种比较（cross-species comparisons），或是分布范围受限的单一物种研究。为规避上述局限，我们采集了横跨美洲大陆的281个采样点的358份家鹪鹩（Troglodytes aedon）鸣声样本，采样范围跨越超100个纬度（52°N - 55°S）。我们发现，北温带与热带种群的鸣声表现与复杂度的多项核心指标存在显著的纬度梯度（latitudinal gradient）差异。此外，我们还证实了南北半球高纬度种群的鸣声模式存在趋同现象。其中，鸣声元素数量与元素产出速率受纬度影响最为显著，二者均随纬度趋近两极而升高；其余指标虽呈现相似趋势但影响强度较弱，相关影响……