Data from: Nest size is predicted by female identity and the local environment in the blue tit, but is not related to genetic or foster mother's nest size

The potential for animals to respond to changing climates has sparked interest in intraspecific variation in avian nest structure since this may influence nest microclimate and protect eggs and offspring from inclement weather. However, there have been relatively few large-scale attempts to examine variation in nests or the determinates of individual variation in nest structure within populations. Using a set of mostly pre-registered analyses, we studied potential predictors of variation in the size of a large sample (803) of blue tit (Cyanistes caeruleus) nests across three breeding seasons at Wytham Woods, UK. Whilst our pre-registered analyses found that individual females built very similar nests across years, there was no evidence in follow-up (post hoc) analyses that their nest size correlated to that of their genetic mother or, in a cross-fostering experiment, to the nest where they were reared. In further pre-registered analyses, spatial environmental variability explained nest size variability at relatively broad spatial scales, and especially strongly at the scale of individual nestboxes. Our study indicates that nest structure is a characteristic of individuals, but is not strongly heritable, indicating that it will not respond rapidly to selection. Explaining the within-individual and within-location repeatability we observed requires further study.动物应对气候变化的潜力，引发了学界对鸟类巢窝结构（avian nest structure）的种内变异（intraspecific variation）的研究兴趣——这是因为巢窝结构可影响巢内微气候（microclimate），并保护卵与幼雏免受恶劣天气侵袭。然而，目前针对种群内巢窝变异，或是巢窝结构个体变异的决定因素开展的大规模研究相对匮乏。本研究采用多数预注册分析（pre-registered analyses）方案，针对英国威瑟姆林地（Wytham Woods）三个繁殖季内采集的803个蓝山雀（Cyanistes caeruleus）巢窝样本的大小变异，探究其潜在影响因子。尽管预注册分析显示，雌性个体在不同繁殖季搭建的巢窝大小极为相似，但后续分析（post hoc）并未发现其巢窝大小与其生母的巢窝大小存在关联；在交叉抚育实验（cross-fostering experiment）中，也未发现其巢窝大小与其被抚育的巢窝存在关联。在进一步的预注册分析中，空间环境变异可在相对宽泛的空间尺度上解释巢窝大小的变异，且在单个巢箱尺度上的解释力尤为显著。本研究表明，巢窝结构属于个体特征，但并不具有强遗传性（heritable），这意味着巢窝结构不会对选择（selection）做出快速响应。而对于我们观测到的个体内与位置内的可重复性（repeatability），其背后机制仍有待进一步研究阐明。