Fig. 6. (A) Phylogenetic tree used to reconstruct the phylogenetically independent contrasts of body mass and flight cost. (B) The effects of flight mode (hovering nectivore, slow flight in both nectivore and non-nectivores, and fast forward flight in non-nectivores) on the costs of flights relative to the expectation from body mass with the effects of lack of phylogenetic independence removed. Flight mode had a large significant effect, with the costs of slow flight in non-nectivores and hovering in nectarivores exceeidng the costs of slow flight in nectarivores and fast flight in non-nectarivores.