Bipedalism has evolved independently in archosaurs and primates, represented today in birds and humans. Birds show exceptional terrestrial locomotor agility and great variety of lifestyles. Yet, the basic arrangement of their hindlimb skeleton and patterns of walking, running, and even hopping, are highly conserved across species. Musculoskeletal morphology of the pelvis and hindlimb have been investigated in a variety of birds, spanning from small crouched (e.g. passerines) to large upright-leg stance (e.g. ratites) species. Birds can generate high muscle power necessary for propulsion through a multi-jointed system of interconnected multi-articulated muscles, functionally connecting the proximal and distal leg. This tendon-network configuration supports energy transfer between the joints for self-stabilisation of striding gaits and self-organisation of the system dynamics, which allows for correction of angular motions with no explicit feedback control. In this work, we will investigate the effect of multi-articular muscles in avian terrestrial locomotion. This will be done in a comparative framework between birds with crouched and upright-limb posture to identify mechanisms of body weight support and control of distal leg mechanics used during gait. 3D time-lapse imaging will be used to investigate joints 3D position in a series of postures representing different stages of the gait cycle. In addition, the full ranges of flexion and extension angles of multi-articular muscles will be quantitatively assessed via tendon travel method.