Figure 2.

(a) Proportion righting (N = 26 birds, number of drops as indicated) and (b) righting mode (N = 26 birds, number of successful rightings as indicated) and (c) vertical force production (N = 5 birds, except for N = 1 at 14 dph; data represent mean ± 1 s.d.) versus age in chukar partridge. Righting via roll, as accomplished by asymmetric wing and leg movements, is used prior to 14 dph. Around 9 dph, birds switch to righting via pitch using symmetric wing motions, and vertical force production increases concomitantly. See text for statistical results.