Data from: Nest material preferences by spotless starlings

The avian nest is an essential structure for offspring development. For adults, nest building entails costs in terms of time, energy and exposure to predators and parasites. Amount and diversity of materials used for nest building depend on their availability and functionality in scenarios of sexual selection and parasitism. Green plants and feathers of different colors have been hypothesized to play key roles in offspring protection against pathogens, and we here experimentally assessed spotless starling (Sturnus unicolor) preferences for pigmented vs. unpigmented feathers and for different green plants (aromatic vs. non-aromatic plants) as nest materials. We predicted a preferential selection of unpigmented feathers and aromatic plants according to the antimicrobial properties of these materials described in the literature. We evaluated these predictions during nest building and during egg-laying stages. As expected, starlings preferentially selected unpigmented feathers both before and during egg laying, while aromatic plants were preferentially selected only during the egg-laying stage. These results suggest that starlings prefer nest materials that enhance antimicrobial protection of their offspring. We also discuss some other, non-exclusive functions that might explain the observed preference for nest materials, especially with regard to their potential role in sexual signaling.

鸟类巢窝是子代发育不可或缺的结构。对于成鸟而言，筑巢需付出时间与能量成本，同时还会增加遭遇捕食者与寄生虫的风险。筑巢所用材料的数量与多样性，取决于其在性选择与寄生情境中的可获得性与功能效用。已有假说提出，不同颜色的绿色植物与羽毛在子代抵御病原体的过程中发挥关键作用；本研究通过实验评估了无斑椋鸟（Sturnus unicolor）对有色羽毛与无色羽毛、以及不同绿色植物（芳香型与非芳香型植物）作为筑巢材料的偏好。基于已有文献中关于这些材料抗菌特性的记载，我们预测鸟类会优先选择无色羽毛与芳香型植物作为筑巢材料。我们在筑巢期与产卵期对上述预测进行了验证。正如预期，椋鸟在产卵前及产卵过程中均优先选择无色羽毛，而芳香型植物仅在产卵期被优先选用。上述结果表明，椋鸟更倾向于选择能够提升子代抗菌防护能力的筑巢材料。本研究同时讨论了其他若干非排他性的功能机制，这些机制或可解释本次研究中观察到的筑巢材料偏好现象，尤其是其在性信号传递方面的潜在作用。