Diversity in owls' (Strigiformes) hindlimbs: evolutionary and ecological influences on hindlimb bone proportions and their relation to prey preferences.

This article focuses on the morphological proportions of hindlimb bones—the femur, tibiotarsus, and tarsometatarsus—in 18 owl species from the families Tytonidae and Strigidae, examining their relationships with prey preferences, body mass, and phylogenetic history. The study finds that owls generally have a short femur and tarsometatarsus but a relatively long tibiotarsus, with bone lengths scaling isometrically with body mass. Phylogenetic analyses reveal strong evolutionary signals in hindlimb morphology, while ecological adaptations are evident when considering all three bones together, such as the long tarsometatarsus in barn owls (Tytonidae) facilitating swift movement for capturing small rodents, and in burrowing owls (Strigidae) enhancing terrestrial locomotion. Ancestral state reconstruction suggests early divergence in dietary specialization, with Tytonidae specializing on small rodents and Strigidae evolving from insectivory toward more generalized or mammal-based diets.