Predation risk affects a broad range of bird behaviours, especially parental care. The adaptive behavioural changes presented by both parents, however, may differ according to different levels of predation risk suffered by each sex. This is especially prominent in sexually dichromatic species, where one of the sexes is more visually conspicuous and hence vulnerable to increased nest predation risk during nest visits. Here, we experimentally investigated how predation risk affects the parental behaviour of a sexually dichromatic Neotropical passerine, the blue‐black grassquit Volatinia jacarina. We used playbacks of known predators and non‐predatorial control sympatric species near nesting pairs in the field. Results show that grassquits modify their behaviour according to predation risk and that this behavioural response is sex‐dependent. Males decrease their nest visit times, become more discreet when moving towards the nest, and stop performing sexual displays after leaving the nest. In contrast, females tend to decrease latency to visit the nest and increase the duration of brooding bouts. These different sex responses reduce nest visual and acoustic detectability, since conspicuous males are readily spotted on nests and cryptic females camouflage nestlings and suppress begging calls. Although these behavioural changes might reduce predation risk, there might be a cost of reduced food load to nestlings and increased brood starvation risk. These changes in nesting activities illustrate the behavioural adaptability of passerines to ensure offspring survival in tropical high predation risk environments.

中文翻译：

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捕食风险对性双色新热带鸣禽的父母关怀的性别特异性影响

捕食风险会影响广泛的鸟类行为，尤其是父母的照料。但是，根据每个性别遭受的掠食风险的不同程度，父母双方的适应性行为变化可能会有所不同。这在有性的两色性物种中尤为突出，其中的一种性别在视觉上更明显，因此在造访巢穴时容易受到增加的巢捕食风险的影响。在这里，我们通过实验研究了捕食风险如何影响性双色性新热带雀形目，蓝黑色草蝇Volatinia jacarina的父母行为。我们在野外嵌套对附近使用了已知的捕食者和非捕食者控制同胞物种的回放。结果表明，草皮动物会根据被捕食的风险改变其行为，并且这种行为反应是性别依赖性的。雄性减少了巢的探访时间，向巢移动时变得更加谨慎，并且在离开巢后停止进行性展示。相比之下，雌性倾向于减少探巢的潜伏期并增加孵卵周期。这些不同的性别反应降低了巢的视觉和听觉检测能力，因为明显的雄性很容易被发现在巢上，而隐秘的雌性则伪装成雏并抑制了乞讨。尽管这些行为改变可能会降低掠食风险，减少雏鸟的食物负担和增加母鸡饥饿风险的代价。嵌套活动的这些变化说明了雀形目的行为适应性，以确保在热带高捕食风险环境中后代的生存。