Meeting Abstract
Birds can actively change the shape of their wings, an ability termed “wing morphing”, which allows for manipulation of mechanical forces and moments. Birds also exhibit substantial differences in wing skeletal morphology, but it is unknown how these anatomical differences affect the range of motion in the wing or whether such patterns are driven by specializations for flight, allometric scaling, or phylogenetic history. We performed a functional anatomical study of range of motion using cadavers of 61 species representing 20 avian orders. Through a multi-camera setup, we recorded for each species the capability of three types of motion at skeletal joints: 1) extension or flexion, 2) elevation or depression (bending), and 3) pronation or supination (twisting). For all taxa, the range of motion of the wing is highly position-dependent with reduced freedom of movement as the wing is extended. Traditional ‘static’ morphometrics, including wing shape at full extension, show high phylogenetic signal and poor associations with flight behaviors or body mass. Range of motion data, however, show flight- and body mass-specific patterns along with relatively low phylogenetic signal. In particular, species that are more prone to gliding, soaring, and/or swimming underwater with their wings show more drastic constraints to range of motion. Collectively, our data demonstrate that avian wing morphing capability has a dynamic evolutionary history that shows stronger concordance with flight style and body mass than does a more traditional view of wing shape.
