强脚树莺的鸣唱行为与领域竞争力的相关性研究

Competitive interactions between animals are often mediated by ritualized aggressive signals that help defuse interactions before they escalate to fighting. These aggressive ritualized signals should be a reliable indication of the willingness of individuals to fight, otherwise, receivers would learn to ignore that signal, leading to the collapse of the signaling system within the population. The singing behavior of oscine passerines are thought to function as ritualized aggressive signals, serving to deter rivals in territorial disputes, but few studies have demonstrated that such behaviors accurately reflect a male’s competitive ability. For this project, we use the singing behavior of the Brownish-flanked Bush Warbler (Horornis fortipes) a common resident passerine in southern China, to investigate the relationship between singing behaviors and male competitive ability in territorial disputes. We use removal experiments of male territory holders to create ‘unoccupied territories’ for floating male individuals. First, we compare the structural characteristics of songs and morphological characteristics between the former territorial holders and the newer residents following removal of the original territory holder. Second, we use playback experiments of male songs with both low and high stimuli, and also manipulate the size of unoccupied territories (following removal of the current territory holder) to determine whether singing intensity is influenced by the turnover of territorial occupation and how singing responses are affected by receiver attributes. Finally, we use habitat surveys and record both the natural (spontaneous) vocalizations of males, and playback-response vocalizations to determine whether males with higher song performance have longer territorial tenure. Our work will identify relationships between singing behaviors and territorial competitive ability in male Brownish-flanked Bush Warblers, and provide new empirical insights into the function and power of ritualized aggressive signals in songbirds.

鸣声是鸟类交流的重要手段，其中鸣禽繁殖季发出的鸣唱，是鸟类研究中最为深入的通讯信号。在领域竞争时，鸟类多利用鸣唱作为仪式化的争斗信号威慑竞争对手，但鸣唱行为能否真实反映信号发出者的竞争力尚存较大争议。本项目以广布于我国南方的留鸟强脚树莺为研究对象，围绕鸣唱能否反映鸟类领域竞争力的重要行为学问题，1）查明不同领域竞争力的强脚树莺在鸣唱行为和体征上的差异；2）探讨领域保卫的收益和代价对强脚树莺鸣唱行为的影响；3）通过长期的监测揭示强脚树莺的鸣唱行为与领域维持时长的相关性。研究结果将为鸣声信号与领域竞争力相关性提供实证，建立基于鸣声的雄鸟竞争力评估方法，提升对鸟类鸣唱功能的了解，并为其它仪式化争斗信号功效的检验提供方法借鉴。

鸣声是鸟类交流的重要手段，其中鸣禽繁殖季发出的鸣唱，是鸟类研究中最为深入的通讯信号。在领域竞争时，鸟类多利用鸣唱作为仪式化的争斗信号威慑竞争对手，但鸣唱行为能否真实反映信号发出者的竞争力尚存较大争议。本项目1）对强脚树莺的领域维持情况进行了监测。在繁殖季进行领域入侵实验。发现保卫领域的行为有很强的重复性，领域攻击性中等的个体领域维持时间最长。2）比较了不同曲目大小的个体在行为上的差异。在黎明鸣唱强度上、领域保卫实验、领域入侵实验中，不同曲目的个体无显著差异。比较了柔声鸣唱和普通鸣唱的差异：柔声鸣唱在短时间回放实验中能诱发更强的领域保卫行为，但在疲倦实验中，普通鸣唱可以诱发更长久的领域保卫行为。3）对鸟类黎明鸣唱进行了研究。播放鸣唱模拟领域入侵，强脚树莺增加次日黎明鸣唱的强度。伴随着强脚树莺黎明鸣唱强度的增加，同域分布的其它常见雀形目鸟类的黎明鸣唱开始时间也普遍提前。该现象体现了鸟类鸣唱在种群构建中的作用。4）尝试利用鸣声进行个体识别，发现个体内的鸣声特征在短期内维持稳定，但在整个繁殖季是否存在变化因鸟种而异。故此建议需要审慎的利用鸟类鸣声的短期特征来区分和监测野生鸟类。本项目的研究，将为鸣声信号与领个体竞争力的关联提供实证，增进对鸟类鸣声功能的了解。