Parent birds employ various strategies to protect their offspring against nest predators. Two well‐researched anti‐nest‐predation strategies involve visual concealment of the nest by way of parental camouflage and egg camouflage. By contrast, camouflage of nest structures is relatively under‐researched, particularly in the case of cup‐nests in trees and bushes. We explored how birds camouflage cup‐nests in nature. Specifically, we tested Hansell’s hypothesis that birds use externally applied pale and white objects such as spider cocoons and lichens to achieve cup‐nest camouflage. To test Hansell’s hypothesis, three complementary experiments were performed: (1) an in situ nest predation experiment; (2) a photo‐based visual search experiment; and (3) contrast analyses using PAT‐GEOM software in IMAGEJ. White paper and chalk spots were used to mimic white objects used by birds in nature. Whereas predation rates in Experiment 1 were not affected by white spots, location rates in Experiment 2 were lower for natural nests with white spots than without white spots. Experiment 3 demonstrated that white spots significantly increased the contrast between different visual elements of nests. It was concluded that white objects can potentially camouflage nests against some nest predators, and that any improved camouflage was probably achieved via disruptive camouflage.

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禽杯巢破坏性迷彩的评估

亲禽采取各种策略来保护其后代免受巢穴掠食者侵害。两种经过充分研究的防巢掠食策略涉及通过父母伪装和鸡蛋伪装的方式对巢进行视觉隐藏。相比之下，对巢结构的伪装研究相对较少，尤其是在树木和灌木丛中的杯状巢的情况下。我们探索了鸟类在自然界如何伪装杯子嵌套。具体来说，我们测试了汉塞尔的假设，即鸟类使用外部应用的苍白和白色物体（例如蜘蛛茧和地衣）来实现杯巢迷彩。为了检验汉塞尔的假设，进行了三个补充实验：（1）原位巢捕食实验；（2）基于照片的视觉搜索实验；（3）使用IMAGEJ中的PAT‐GEOM软件进行对比分析。白皮书和粉笔斑点被用来模仿鸟类在自然界中使用的白色物体。尽管实验1中的捕食率不受白点影响，但是实验2中具有白点的自然巢的定位率比没有白点的自然巢低。实验3表明，白点显着提高了巢中不同视觉元素之间的对比度。得出的结论是，白色物体可能会伪装成巢抵靠某些巢穴掠食者，并且任何改进的伪装都可能是通过破坏性伪装来实现的。