We explored adaptive factors affecting the preformative molt in the passerine family Cardinalidae, and concluded that the ancestor inhabited forest habitats and underwent a partial preformative molt that included wing coverts but not primaries. Later radiations within the family appeared to be characterized by transitions from forests toward more open habitats, and such transitions also correlated positively with increased preformative molt investment, plumage signaling, and flight. While previous studies had highlighted the role of time and energy constraints in the evolution of the preformative molt in passerines, we conclude that adaptation to the physical environment has had a greater influence than constraints on the evolution of this molt in Cardinalidae. Using molt data from 430 individuals from 41 of the 51 Cardinalidae species, we tested whether social and environmental factors (delayed plumage maturation and habitat openness), as well as that of physiological and time constraints (body mass, migration distance, and breeding latitude), have influenced the evolution of the preformative molt in this family. We predicted that these five factors could relate to the extent of the preformative molt in terms of energy investment, plumage signaling, and flight. We also examined whether or not the presence of an auxiliary preformative molt correlated to the extent of the preformative molt. We found a strong phylogenetic signal for the preformative molt in Cardinalidae due to shared ancestry, with habitat openness correlating significantly with increased molt extent. We also found a very strong relationship with the auxiliary preformative molt, indicating that both episodes form part of the early life molt strategy in this family. Evolutionary histories and the environments to which each taxonomic group has adapted can diverge across passerines, and we expect that future studies will further discover the nature and strength of the evolutionary drivers of preformative molt.

中文翻译：

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红雀科动物蜕皮的进化与从森林到开放栖息地的转变有关

我们探索了影响雀形目科红雀科动物蜕皮的适应因素，并得出结论认为，该祖先居住在森林栖息地并经历了部分蜕皮，包括翼覆羽但不包括初级蜕皮。该科后期的辐射特征似乎是从森林向更开放的栖息地转变，这种转变也与前期蜕皮投资、羽毛信号和飞行的增加呈正相关。虽然以前的研究强调了时间和能量限制在雀形目动物蜕皮进化中的作用，但我们得出结论，对物理环境的适应比对红雀科这种蜕皮进化的限制具有更大的影响。使用来自 51 个红雀科物种中的 41 个的 430 个个体的蜕皮数据，我们测试了社会和环境因素（羽毛成熟延迟和栖息地开放性）以及生理和时间限制（体重、迁移距离和繁殖纬度）是否影响了该家族中前体蜕皮的进化。我们预测，这五个因素可能与能量投资、羽毛信号和飞行方面的前期蜕皮程度有关。我们还检查了辅助预蜕皮的存在是否与预蜕皮的程度相关。由于共同的祖先，我们发现红雀科的前期蜕皮具有很强的系统发育信号，栖息地开放性与蜕皮程度的增加显着相关。我们还发现与辅助预蜕皮有很强的关系，表明这两个事件都是这个家庭早期蜕皮策略的一部分。每个分类群所适应的进化历史和环境可能因雀形目而异，我们预计未来的研究将进一步发现蜕皮进化驱动因素的性质和强度。