Animals need to recognise predators to assess threats and adjust their behaviour accordingly. Acoustic cues produced to attract mates may also be intercepted by predators, and signallers can use both visual and acoustic cues to detect predators and initiate escape or defensive behaviours. Here, to test whether Ueno’s brown frogs (Rana uenoi) advertising during daytime are able to visually and aurally recognize predatory birds, we monitored calling activity at 27 active breeding sites where birds were also known to occur. Based on visual and aural observations, frogs were significantly less likely to be calling when birds were present than when absent. However, we failed to determine whether male R. uenoi distinguished among predator and non-predator species, responding to the presence of all bird species with cessation of calling. While daytime calling activity decreased in the presence of birds, the maximum egg clutch count per site used as a proxy for reproductive output was unaffected by daytime presence of birds. Our results suggest that R. uenoi uses visual cues to detect disturbances, but that its ability to visually assess the risks posed by individual species is minimal.

中文翻译：

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上野的棕蛙 Rana uenoi 在白天的鸟类面前不分青红皂白地停止呼唤

动物需要识别捕食者以评估威胁并相应地调整它们的行为。为吸引配偶而产生的声音提示也可能被捕食者拦截，信号员可以使用视觉和声音提示来检测捕食者并启动逃跑或防御行为。在这里，为了测试白天上野的棕蛙 (Rana uenoi) 广告是否能够在视觉和听觉上识别掠食性鸟类，我们监测了 27 个已知鸟类也会出现的活跃繁殖地的叫声活动。根据视觉和听觉观察，与鸟类不在时相比，当鸟类在场时，青蛙鸣叫的可能性要小得多。然而，我们未能确定雄性 R. uenoi 是否区分捕食者和非捕食者物种，对所有鸟类的存在做出反应并停止呼叫。虽然在鸟类存在的情况下白天的叫声活动减少，但用作生殖产量代理的每个地点的最大卵离合器计数不受白天鸟类存在的影响。我们的结果表明，R. uenoi 使用视觉线索来检测干扰，但其视觉评估单个物种带来的风险的能力很小。