Figure 2.

Migration promotes diversification in all species-rich orders. Posterior distributions of migratory (red) and sedentary (green) speciation—symmetrical and asymmetrical—, extinction, net diversification and anagenetic transition rates, computed using the best-fitting model. In the majority of groups, in comparison with sedentary birds, migratory birds have higher speciation rates and lower—or equal—extinction rates, resulting in higher net diversification rates. Anagenetic transition rates are very low. Posterior distributions not different between migratory and sedentary species are shown in grey. Posterior distributions estimates are from MCMC analyses on all birds, using the best-fitting model.