Figure 7.

The relationships between speed and either glide angle or orientation relative to the flow (angle of attack: AOA) of the body, wing and tail. (a) The relationship between the glide angle and speed was not significant for any bird. (b–d) Angle of attack tended to decrease with increased speed. The angle of attack was defined by the pitch of the (b) body coordinate system; (c) wing coordinate system, i.e. the plane of the wing; and (d) plane of the tail. Thick lines indicate statistically significant relationships. (b,c) Thin lines are not statistically significant, but were used to compute residuals for other analyses.