Abstract
The capacity for aerial manoeuvring shaped the evolution of flying animals. Here we evaluate consequences of aviaian morphology for aerial performance1, 2 by quantifying static stability and control effectiveness of physical models3 for numerous taxa sampled from within the lineage leading to birds (Avialae4). Results of aerodynamic testing are mapped phylogenetically5–9 to examine how manoeuvring characteristics correlate with tail shortening, fore-and hindwing elaboration, and other morphological features10. In the evolution of the Avialae we observe shifts from static stability to inherently unstable aerial planforms; control effectiveness also migrated from tails to the forewings. These shifts suggest that some degree of aerodynamic control and and capacity for manoeuvring preceded the evolution of strong power stroke. The timing of shifts suggests features normally considered in light of development of a power stroke also play important roles in control.