Data from: Multi-functional crest display in hoopoes Upupa epops

Animals can engage in visual displays, which may target conspecifics, heterospecifics or both. Here we studied the function of the flamboyant crest-raising display of hoopoes (Upupa epops) in experiments performed with males in captivity. Males were exposed to sounds of a conspecific (male hoopoe song), a potential predator (human voice), and two controls (the song of a blackbird, Turdus merula, and background noise). These stimuli were presented to males in the presence and absence of females. Males raised the crest with a significantly higher probability when confronted with stimuli indicating potential threats (rival mate or predator) than with controls. The crest display was frequent when confronted with both kinds of threats independently of the presence of a female, suggesting that it was directed to the predator and the rival male. The probability of raising the crest was not related to body condition, and there was a marginally but not significant negative relationship between probability of raising the crest and the number of black spots on the crest feathers, which may suggest that crest display could be informing about male quality. Therefore, male hoopoes display the crest in a heterospecific context in response to detection of potential threats, which could be a deceptive or pursuit-deterrent signal. The results also support a role of the crest in sexual selection, suggesting that crest display in male hoopoes may serve multiple functions.动物可开展视觉展示行为，此类行为的目标可为同种个体（conspecifics）、异种个体（heterospecifics），或二者兼具。本研究针对戴胜 (Upupa epops) 华丽醒目的抬冠展示行为的功能展开探究，实验对象为圈养雄性戴胜。实验中，雄性戴胜接受了四类声源刺激：同种鸣声（雄性戴胜鸣唱声）、潜在天敌的声音（人类人声），以及两组对照声源——乌鸫 (Turdus merula) 鸣唱声与背景噪音。上述声源刺激分别在有雌性戴胜在场、无雌性戴胜在场两种实验情境下呈现给雄性戴胜。当雄性戴胜接收到代表潜在威胁（配偶竞争者或天敌）的刺激声源时，其抬冠行为的发生概率显著高于对照声源情境。无论雌性戴胜是否在场，雄性在面对这两类威胁声源时均会频繁展现抬冠行为，这表明该展示行为的目标对象为天敌与雄性竞争者。抬冠行为的发生概率与雄性戴胜的身体状况并无关联，但与冠羽上黑斑的数量呈现出边际显著但未达统计学显著性的负相关关系，这提示抬冠展示或许能够传递关于雄性个体质量的信息。综上，雄性戴胜会在异种互动情境下，针对潜在威胁的侦测展现抬冠行为，该行为或为一种欺骗性或阻吓追击的信号。本研究结果同时支持抬冠行为在性选择中的作用，表明雄性戴胜的抬冠展示可能兼具多重功能。