A full evaluation of the applicability of aerodynamic scaling rules must be based, not on theoretically derived speeds, but on empirical measurements of airspeeds of a wide variety of bird species in natural cruising flight. Here, we present tracking radar measurements of flight speeds of 138 species from six main monophyletic groups, which were analysed in relation to biometry (m, S, and wingspan b) and evolutionary origin (as reflected by phylogenetic group).

A full evaluation of the applicability of aerodynamic scaling rules must be based, not on theoretically derived speeds, but on empirical measurements of airspeeds of a wide variety of bird species in natural cruising flight. Here, we present tracking radar measurements of flight speeds of 138 species from six main monophyletic groups, which were analysed in relation to biometry (m, S, and wingspan b) and evolutionary origin (as reflected by phylogenetic group).