Abstract Birds communicate their motivation and willingness to escalate a territorial conflict with a variety of agonistic signals. One of these, song-type switching, has been suggested to be a conventional signal in male–male interactions. However, this behavior does not show a consistent pattern across species. In this study, we asked whether variation in song-switching rate carries a message for song receivers among territorial chaffinches, Fringilla coelebs . Chaffinch song is well described, but only a few studies have focused on the communicative function of song-type switching or bout duration. Using data from playback experiments, we show here that variation in song-type switching rate affects the response of chaffinches. In response to the low switching rate treatment, territorial males began to sing later, produced fewer songs and more rain calls, decreased flight intensity, and spent more time close to the speaker than during playback of songs with a high switching rate. Our results provide strong evidence that the song-type switching rate is an agonistic signal in the chaffinch and that territorial males exhibit a stronger response toward rivals that sing with a lower song-type switching rate. A secondary purpose of our study was to determine the receivers’ response with respect to their own song rate and song repertoire. We found that the reaction of tested males was correlated with their own spontaneous song rate. This implies that a male’s response to stimuli may be predicted on the basis of his own song output. Significance statement Using playback experiments, we show that birds’ responses to simulated territorial intrusion vary not only with the type of stimulus but also with the tested males’ spontaneous song output. We found that, from the perspective of the song receiver, variation in switching rate carries a message for territorial chaffinches. Our findings add a new example of agonistic signaling in which territorial males exhibit a stronger response toward rivals singing with lower song-type switching rate, which up to now has only been demonstrated in a few species. Moreover, our results show that a male’s response to playback could be predicted using his song output. This may be associated with motivation and willingness to escalate a conflict and could possibly also indicate a male’s quality.

中文翻译：

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在模拟入侵期间，金雀花中的歌曲类型切换率携带消息

摘要 鸟类通过各种对抗性信号来表达他们升级领土冲突的动机和意愿。其中之一，歌曲类型转换，已被认为是男性与男性互动中的常规信号。然而，这种行为并没有显示出跨物种的一致模式。在这项研究中，我们询问了歌曲切换率的变化是否会为领土上的松鼠（Fringilla coelebs）中的歌曲接收者带来信息。Chaffinch 歌曲被很好地描述，但只有少数研究集中在歌曲类型转换或回合持续时间的交际功能上。使用来自播放实验的数据，我们在这里展示了歌曲类型切换率的变化会影响花瓶的响应。为了应对低转换率的待遇，领地雄性开始唱歌较晚，与播放具有高切换率的歌曲相比，产生更少的歌曲和更多的雨声，降低飞行强度，并在靠近扬声器的位置花费更多时间。我们的结果提供了强有力的证据，表明歌曲类型转换率是金雀花中的激动信号，并且领土雄性对以较低歌曲类型转换率唱歌的竞争对手表现出更强的反应。我们研究的第二个目的是确定接收者对他们自己的歌曲率和歌曲曲目的反应。我们发现被测男性的反应与他们自己的自发歌曲率相关。这意味着可以根据他自己的歌曲输出来预测男性对刺激的反应。意义声明 使用回放实验，我们表明，鸟类对模拟领土入侵的反应不仅因刺激类型而异，还因受测雄性自发的歌曲输出而异。我们发现，从歌曲接收者的角度来看，切换率的变化会为领地花瓶传递信息。我们的研究结果增加了一个激动信号的新例子，其中领土雄性对以较低的歌曲类型转换率唱歌的竞争对手表现出更强的反应，到目前为止，这仅在少数物种中得到证实。此外，我们的结果表明，可以使用他的歌曲输出来预测男性对播放的反应。这可能与升级冲突的动机和意愿有关，也可能表明男性的素质。从歌曲接收者的角度来看，转换率的变化为领土金龟子传递了一个信息。我们的研究结果增加了一个激动信号的新例子，其中领土雄性对以较低的歌曲类型转换率唱歌的竞争对手表现出更强的反应，到目前为止，这仅在少数物种中得到证实。此外，我们的结果表明，可以使用他的歌曲输出来预测男性对播放的反应。这可能与升级冲突的动机和意愿有关，也可能表明男性的素质。从歌曲接收者的角度来看，转换率的变化为领土金龟子传递了一个信息。我们的研究结果增加了一个激动信号的新例子，其中领土雄性对以较低的歌曲类型转换率唱歌的竞争对手表现出更强的反应，到目前为止，这仅在少数物种中得到证实。此外，我们的结果表明，可以使用他的歌曲输出来预测男性对播放的反应。这可能与升级冲突的动机和意愿有关，也可能表明男性的素质。到目前为止，这仅在少数物种中得到证实。此外，我们的结果表明，可以使用他的歌曲输出来预测男性对播放的反应。这可能与升级冲突的动机和意愿有关，也可能表明男性的素质。到目前为止，这仅在少数物种中得到证实。此外，我们的结果表明，可以使用他的歌曲输出来预测男性对播放的反应。这可能与升级冲突的动机和意愿有关，也可能表明男性的素质。