The neuromuscular control of wing morphing in response to upward gusts during gliding flight in doves

Real-world airflows are complex, and perturbations have likely served as selective pressures upon flying organisms. Preflexes are hypothesized to help maintain stability during gust perturbations, but this has rarely been tested in flying vertebrates. Moreover, the relative contributions of reflexive and preflexive mechanisms to perturbation recovery are currently unknown. To determine the neuromuscular control of gust rejection mechanisms employed by gliding birds, we flew ringneck doves (Streptopelia risoria) in a wind tunnel operating at 9 m s-1 while inducing gusts of 0.5 m s-1. We measured three-dimensional kinematics and contractile behaviour in four wing muscles (pectoralis, biceps brachii, extensor carpi radialis and flexor carpi ulnaris). Our results are consistent with the hypothesis that preflexes facilitate gust rejection: in response to gusts, wing elevation increased near-instantaneously then halted without a change in pectoralis activity. After a delay, motor-unit recruitment was modulated in all measured muscles except the biceps, revealing reflexive responses. Doves rejected gusts using only subtle changes to wing kinematics and neuromuscular control, emphasizing the high degree of control birds maintain during flight in turbulence. Initial wing elevation followed by modulation of distal wing kinematics echoes prior findings in owls, possibly indicating a common gust rejection mechanism in gliding birds.