Department of Behavioural Ecology, Institute of Environmental Biology, Faculty of Biology, Adam Mickiewicz University, Uniwersytetu Poznańskiego 6, 61-614, Poznań, Poland.
Sci Rep. 2024 Feb 21;14(1):4252. doi: 10.1038/s41598-024-53867-7.
We investigated within- and between-individual song variation and song-based neighbour-stranger discrimination in a non-learning bird species, the blue-headed wood-dove (Turtur brehmeri), which inhabits lowland rainforests of West and Central Africa. We found that songs of this species are individually specific and have a high potential for use in individual recognition based on the time-frequency pattern of note distribution within song phrases. To test whether these differences affect behaviour, we conducted playback experiments with 19 territorial males. Each male was tested twice, once with the songs of a familiar neighbour and once with the songs of an unfamiliar stranger. We observed that males responded more aggressively to playback of a stranger's songs: they quickly approached close to the speaker and spent more time near it. However, no significant differences between treatments were observed in the vocal responses. In addition, we explored whether responses differed based on the song frequency of the focal male and/or that of the simulated intruder (i.e., playback), as this song parameter is inversely related to body size and could potentially affect males' decisions to respond to other birds. Song frequency parameters (of either the focal male or the simulated intruder) had no effect on the approaching response during playback. However, we found that the pattern of response after playback was significantly affected by the song frequency of the focal male: males with lower-frequency songs stayed closer to the simulated intruder for a longer period of time without singing, while males with higher-frequency songs returned more quickly to their initial song posts and resumed singing. Together, these results depict a consistently strong response to strangers during and after playback that is dependent on a male's self-assessment rather than assessment of a rival's strength based on his song frequency. This work provides the first experimental evidence that doves (Columbidae) can use songs for neighbour-stranger discrimination and respond according to a "dear enemy" scheme that keeps the cost of territory defence at a reasonable level.
我们研究了一种非学习型鸟类，蓝头木鸽（Turtur brehmeri），在个体和个体间歌曲变化以及基于歌曲的邻居-陌生者辨别能力。我们发现，这种物种的歌曲具有个体特异性，并且基于歌曲短语中音符分布的时频模式，具有很高的个体识别潜力。为了测试这些差异是否会影响行为，我们对 19 只领地雄性进行了播放实验。每个雄性都接受了两次测试，一次是播放熟悉邻居的歌曲，一次是播放陌生陌生者的歌曲。我们观察到，雄性对陌生者的歌曲播放反应更为激烈：它们迅速接近扬声器，并在其附近停留的时间更长。但是，在处理方面，在发声反应方面没有观察到明显的差异。此外，我们还探讨了响应是否基于焦点雄性和/或模拟入侵者（即播放）的歌曲频率而有所不同，因为该歌曲参数与体型成反比，并且可能会影响雄性对其他鸟类做出反应的决定。歌曲频率参数（无论是焦点雄性还是模拟入侵者的）在播放期间对接近反应没有影响。但是，我们发现播放后的反应模式受到焦点雄性歌曲频率的显著影响：具有较低频率歌曲的雄性在不唱歌的情况下，更接近模拟入侵者并停留更长时间，而具有较高频率歌曲的雄性则更快地返回其初始歌曲帖子并恢复唱歌。总的来说，这些结果描绘了一种在播放期间和之后对陌生者始终保持强烈反应的模式，这种反应依赖于雄性的自我评估，而不是根据他的歌曲频率评估竞争对手的实力。这项工作首次提供了实验证据，表明鸽子（Columbidae）可以使用歌曲进行邻居-陌生者辨别，并根据“亲爱的敌人”计划做出反应，该计划使领地防御的成本保持在合理水平。
