Communication value of mistakes in dark-eyed junco song

Sexual signals contain information on individual quality or motivation, and most explanations for their reliability are based on signal costs. A recent suggestion is that signaling mistakes, defined as deviations from typical signal design, provide cues on individual quality, contributing to reliable communication even when signal design is not costly. We describe several atypical song traits in dark-eyed juncos (Junco hyemalis) that may be mistakes during song production or development and occur in up to 6% of songs. These putative mistakes were more frequent in an urban versus a wildland population, and individuals differed in their frequency of mistakes. Some atypical signals were more frequent in younger males or were negatively related to paternity success, supporting the hypothesis that fewer mistakes indicate individual quality. We also discuss unexpected results, such as some atypical signals being more frequent in more ornamented males and in songs with lower performance demand...

性信号（sexual signals）承载着个体品质或动机相关的信息，针对其可靠性的多数解释均以信号成本（signal costs）为理论基础。近期有研究提出，信号失误（signaling mistakes）——即偏离典型信号设计的现象——可传递个体品质的相关线索，即便信号设计本身无需付出成本，也能助力可靠的信息传递。本研究对暗眼灯草鹀（dark-eyed juncos，学名Junco hyemalis）的若干非典型鸣唱特征展开分析，这类特征可能源于鸣唱生成或发育阶段的失误，在全部鸣唱中的出现比例最高可达6%。这些疑似信号失误在城市种群中的出现频率显著高于野生种群，且不同个体的失误频率存在显著差异。部分非典型信号在年轻雄鸟中出现频率更高，或与父权成功率呈负相关，这一结果支持"信号失误越少，个体品质越高"的假说。本研究还探讨了若干意外发现，例如部分非典型信号在羽饰更为华丽的雄鸟以及鸣唱表现需求更低的鸣唱中出现频率更高……