Figure 3.

Changes in wing shape across Aves. Ancestral state estimation for wing shape based on (a) ventral PC1 scores and (b) dorsal PC1 scores using weighted squared-change parsimony and the Jarvis et al. [51] phylogenetic tree. Vector-based output was used to visualize how shape differed across the phylogeny. Each landmark of the consensus wing represents the vector base, and arrows show the direction and magnitude of variation at any point along the wing. Anseriformes, Podicipediformes, Charadriiformes and waterbirds (Aequornithia) show a trend towards more elongate primary covert feathers and shorter secondary feathers, regardless of flight style or body size. Core ‘higher landbirds’ show a trend toward shorter primary coverts.