Meeting Abstract
Wingtip shape has several functional consequences in avian flapping flight, both in aerodynamic effects and in inertial costs. Although the shape and kinematics of the distal wing exert a strong influence on function, variability in the ligaments and skeleton that support the primary flight feathers of the distal wing segment is largely unexplored. This is especially true for the ‘land birds’ historically grouped as Coraciiformes and Piciformes (rollers, woodpeckers, and allies). Many of these taxa display odd bony features in the hand that have taxonomic utility, but only limited functional and anatomical context. This study addresses the question of whether variation in the hand skeleton is consistently associated with variation in wingtip shape, feeding ecology, or migration pattern. Skeletal morphology was summarized by 3D geometric morphometrics from microCT scans of alcoholic and skeletal specimens. Primary feather length measurements were taken from alcoholic and spread wing preparations to assess wingtip shape. Feeding and migration behaviors were scored as a series of binary variables from published accounts, then submitted to principal coordinate ordination to assess behavioral variability. The current sample includes n = 24 taxa, evenly distributed within the crown clade, with additional data collection to extend to ~10% of the 675 crown taxa. Preliminary comparisons suggest that interactions between migratory behavior, feeding ecology, and body size are associated with distinct wingtip shapes. While there are clade-specific skeletal morphologies associated with elongate middle primary feathers (VI-VIII), skeletal attachments of the distalmost primary feathers (IX-X) show consistent features associated with feather length across clades. The patterns seen within rollers, woodpeckers, and related taxa point to more general anatomical constraints on wing shape evolution within birds.
