very young ruby-throated hummingbird perched on slender tree branch - trochilidae

young ruby-throated hummingbird perched branch slender tree trochilidae hummingbirds birds native americas constituting biological family trochilidae smallest bird humming sound created beating wings flap high frequencies audible humans highest mass-specific metabolic rate homeothermic animal conserve energy nightly foraging torpor state hibernation slowing normal rate feathered feathers pollinator tiny small delicate green irre iridescent shiny fledgling