Male-drive evolution of genomic sequences in birds. (A). Male-to-female mutation bias of 45 bird species. We show the degree of male-driven evolution (α) inferred from comparing intronic substitution rates between Z chromosomes and macrochromosomes, as well as their confidence intervals. (B-E). The association between synonymous substitution rates vs. life history traits. BMR: Basal Metabolic Rate. The numbers of data points vary by the species with certain life history trait data available.