Capilla-Lasheras Pablo, Bondía Blanca, Aguirre José I
Institute of Biodiversity, Animal Health and Comparative Medicine University of Glasgow Glasgow UK.
Department of Biodiversity, Ecology and Evolution Universidad Complutense de Madrid Madrid Spain.
Ecol Evol. 2021 Mar 12;11(7):3084-3092. doi: 10.1002/ece3.7234. eCollection 2021 Apr.
Adjusting the composition of their nests, breeding birds can influence the environmental conditions that eggs and offspring experience. Birds often use feathers to build nests, presumably due to their insulating properties. The amount of feathers in nests is often associated with increased nestling survival and body condition. However, it is unclear whether these putative beneficial effects of adding feathers to nests are relevant in a wide range of environmental conditions. Here, we combine data on weather conditions and feathers in nests (i.e., nest composition) to investigate their relative contribution to reproductive success in the Eurasian tree sparrow (). Specifically, we investigate whether the effect of weather conditions on breeding success is modulated by the amount of feathers added to the nest. We found a strong negative effect of rainfall on the number of nestlings that successfully fledged per breeding attempt, but this negative effect was not mitigated by the amount of feathers in nests. We also found that the amount of feathers in nests varied along the breeding season, with nests containing more feathers early in the breeding season, when temperatures were lower. Despite considerable variation in nest composition, our results do not suggest an important role of feathers in nests protecting eggs or nestling tree sparrows against fluctuations in environmental conditions.
通过调整鸟巢的构成，繁殖期的鸟类能够影响鸟蛋和雏鸟所经历的环境条件。鸟类常常使用羽毛来筑巢，大概是因为羽毛具有隔热性能。鸟巢中羽毛的数量通常与雏鸟存活率的提高以及身体状况相关。然而，向鸟巢中添加羽毛所带来的这些假定的有益效果在广泛的环境条件下是否相关尚不清楚。在此，我们结合天气状况和鸟巢中羽毛（即鸟巢构成）的数据，来研究它们对欧亚树麻雀繁殖成功率的相对贡献。具体而言，我们研究天气状况对繁殖成功率的影响是否会因添加到鸟巢中的羽毛数量而受到调节。我们发现降雨对每次繁殖尝试中成功离巢的雏鸟数量有强烈的负面影响，但这种负面影响并未因鸟巢中羽毛的数量而减轻。我们还发现，鸟巢中羽毛的数量在繁殖季节中有所变化，在繁殖季节早期温度较低时，鸟巢中含有更多的羽毛。尽管鸟巢构成存在相当大的差异，但我们的结果并未表明鸟巢中的羽毛在保护鸟蛋或雏鸟免受环境条件波动影响方面发挥重要作用。
