Meeting Abstract
Hovering is an energetically expensive mode of flight and places high mechanical stress on the avian body. Knowledge of the morphological adaptations for hovering is necessary to elucidate how this behavior evolves and to understand which species are capable of hovering and why. However, only hummingbirds have been thoroughly studied for their morphological adaptations to hovering. We evaluated sunbirds (Family: Nectariniidae), a taxon that includes species that are incapable of hovering and species that routinely hover. We collected linear measurements of wing, tarsus, and bill length from 75 sunbird species. We also collected linear and areal measurements of long bones from 40 sunbird species using computed tomography scanning. The species we chose covered a wide range of hovering abilities and resident elevations. After accounting for phylogenetic history, we found that overall bird size increased with elevation, and that the ulna is rounder in birds that hover more frequently. Skeletal morphology can thus provide clues for behavior in closely related species, and elucidate the evolutionary origins of hovering behavior.
