Materials suitable for anatomical research of raptorial birds are rare. Bird-eating raptors show distinct inter-sexual differences in body size and parental roles. The large females catch larger prey and prepare small morsels to feed their young using their hooked beaks. Here, we investigated the architectural properties of different jaw muscles of the Japanese sparrowhawk (Accipiter gularis) and examined whether there is sexual dimorphism in their architectural design. The results showed that musculus depressor mandibulae, the opener of the lower jaw, was characterized by relatively long fascicle length, whereas musculus pterygoideus was characterized by its larger mass and physiological cross-sectional area (PCSA) in both sexes. Females have the potential capacity to produce rapid and strong bites by their significantly longer fascicle length of M. depressor mandibulae and larger mass and PCSA of M. pterygoideus. For body size-matched gender, jaw muscles of males had fibres of relatively longer length than females, enabling greater velocity and excursion. Architectural characteristics of jaw muscles, together with the absolute dimorphism (the fascicle length of M. depressor mandibulae, the muscle mass and PCSA of M. pterygoideus) and relative dimorphism in the muscle mass of M. pterygoideus, reflect dietary difference and asymmetric parental roles between the sexes.

The fore‐ and hindlimbs of birds are specialized to perform different functions. The growth patterns of limb bones and their relationship with the ontogeny of locomotion are critical to our understanding of variation in morphological, physiological and life‐history traits within and among species. Unfortunately, the ontogenetic development of limb bones has not been well explored, especially in altricial birds. In this study, we sampled the entire measurements of the pigeon (Columba livia) of individual skeletons, to investigate the ontogenetic allometry of limb bones by reduced major axis regression. The ulna and humerus were found to be positively allometric in relation to body mass, with the ulna growing more rapidly than the humerus. Together with previous data, this suggests that strong positive allometric growth in forelimb bones could be a common trend among diverse Carinatae groups. Hindlimb was dominated by positive allometry, but was variable in the growth of the tarsometatarsus which included three allometric patterns. A greater dorsoventral diameter in the midsection of the humerus and ulna confers superior bending resistance and is ideal for flapping/gliding flight. Shape variation in the midsection of different hindlimb components reflects different mechanical loading, and the markedly inverse trend between the tibiotarsus and tarsometatarsus before 28 days of age also suggests loading change before fledging. Before fledging, the growth of the leg bones was prior to that of the wing bones. This kind of asynchronous development of the fore‐ and hindlimbs was associated with the establishment and improvement of different functions, and with shifts in the importance of different functions over time.