 Of those species that have been measured in wind tunnels, their top speeds exceed and some species can dive at speeds in excess of .Hummingbirds have the highest mass-specific metabolic rate of any homeothermic animal.To conserve energy when food is scarce, and nightly when not foraging, they can go into torpor, a state similar to hibernation, slowing their metabolic rate to 1/15th of its normal rate.