abstract: Flight performance trade‐offs and functional capacities of ruby‐throated hummingbirds (Archilochus colubris L.) were studied using an integrative approach. Performance limits were measured by noninvasively challenging birds with two strenuous forms of flight: hovering in low‐density gas mixtures (a lift assay for the capacity to generate vertical force) and fast forward flight in a wind tunnel (a thrust assay for the capacity to generate horizontal force). Functional capacities during hovering were measured by simultaneously collecting metabolic data using respirometry and information on wing‐beat kinematics for aerodynamic analysis. Intraspecific differences in flight capacity, presumably reflecting diverse selective forces because of sexual dimorphism, migration, and plumage renewal, were then compared. Birds with shorter wings (adult males) or with increased body weight displayed a reduced hovering capacity, although their maximum flight speed was unaffected by such morphological changes. Bir...