Appendix S2

Information on testicular melanization, body mass (g), mitochondrial DNA substitution rate, and eu- and pheomelanin-based plumage coloration in 134 species of birds. TM: number of individuals with testicular melanization during the breeding and non-breeding seasons, and during periods that could not be assigned to any phase of the reproductive cycle (i.e. unknown dates). '-' means absence of data for the corresponding reproductive phase. Total N: total number of individuals examined. EB: eumelanin-based plumage color score. PB: pheomelanin-based plumage color score. Mutation rate refers to species-specific mtDNA base pair substitution rate as reported by Nabholz et al. (2008, 2009). All data except substitution rate are for adult males.本数据集涵盖134种鸟类的睾丸黑色素沉着情况、体重（单位：克）、线粒体DNA（mitochondrial DNA, mtDNA）替换率，以及基于真黑色素（eumelanin）和褐黑色素（pheomelanin）的羽色特征数据。TM：在繁殖季、非繁殖季以及无法归为生殖周期任一阶段（即日期未知）的时段内，出现睾丸黑色素沉着的个体数量。符号“-”代表对应生殖阶段无有效数据。Total N：受检个体总数。EB：基于真黑色素的羽色评分。PB：基于褐黑色素的羽色评分。突变率：指Nabholz等人（2008、2009）报道的物种特异性线粒体DNA碱基对替换率。除替换率外，其余所有数据均取自成年雄性个体。