Recent theory in animal communication predicts that a group’s communicative complexity is connected to its social complexity. Social complexity has typically been measured using group size as an index, with larger groups thought to be more complex than smaller groups. However, group size alone does not account for other social differences that could influence the diversity of interactions within a group that may influence communication. In this study, we asked if other social factors could influence communicative behavior in groups by testing the influence of group composition in the Carolina chickadees, Poecile carolinensis. We recorded the vocal behavior of four wild-caught captive groups of familiar chickadees (birds caught from the same naturally occurring flock) and four wild-caught captive groups of unfamiliar chickadees (birds caught from all different naturally occurring flocks) and then analyzed vocalizations by assessing the note types birds used in their chickadee calls. Flocks of familiar chickadees used fewer introductory notes, more C notes, and fewer hybrid notes in their calls compared to flocks of unfamiliar chickadees. Communicative complexity, measured by zero- and first-order uncertainty, did not differ between conditions. We conclude that note composition of call, but not call complexity, varies with flock-mate familiarity.

中文翻译：

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队友的熟悉程度会影响山雀叫声的成分

动物交流中的最新理论预测，群体的交流复杂性与其社会复杂性有关。社会复杂性通常是使用群体规模作为指标来衡量的，较大的群体被认为比较小的群体更为复杂。但是，仅团体规模并不能解决可能影响团体内部互动多样性的其他社会差异，从而影响交流。在这项研究中，我们通过测试卡罗来纳州山雀Poecile carolinensis的群体组成的影响，询问其他社会因素是否会影响群体的交流行为。我们记录了四个熟悉的山雀的野生捕获圈养小组（从同一自然发生的鸟群捕获的鸟）和四个不熟悉的山雀的野生捕获圈养小组（从所有不同的自然发生的群捕获的鸟）的发声行为，然后通过评估他们在山雀叫声中使用的音符类型。与不熟悉的山雀群相比，熟悉的山雀群在呼叫中使用的介绍音符，更多的C音符和混合音符更少。通过零阶和一阶不确定性衡量的交流复杂性在条件之间没有差异。我们得出结论，通话的音调组成（而不是通话复杂性）随羊群的熟悉程度而变化。