Presumably, due to a rapid early diversification, major parts of the higher-level phylogeny of birds are still resolved controversially in different analyses or are considered unresolvable. To address this problem, we produced an avian tree of life, which includes molecular sequences of one or several species of ∼ 90% of the currently recognized family-level taxa (429 species, 379 genera) including all 106 for the non-passerines and 115 for the passerines (Passeriformes). The unconstrained analyses of...