The hindlimbs play a crucial role in bird locomotion, making the biomechanical properties of the musculoskeletal system in these limbs a focal point for researchers studying avian behaviour. However, a comprehensive analysis of the mechanical performance within the long bones of hindlimbs during locomotion remains lacking. In the present study, the strain and deformation of the femur of Cabot's Tragopans (Tragopan caboti) were estimated. We employed inverse simulation to calculate the force and moment of femoral muscles during mid-stance terrestrial locomotion and conducted finite element analysis to calculate femoral strain. Results showed that during mid-stance, the femur experiences combined deformation primarily characterized by torsion, bending, and compression. It emphasises the importance of considering the influence of varying loads on bone adaptation when investigating bone form-function relationships. Muscles were found to play a significant role in offsetting joint loads on the femur, subsequently reducing the deformation and overall strain on the bone. This reduction enhances femoral safety during locomotion, allowing birds to meet mechanical demands while maintaining a lightweight bone structure. Notably, the M. iliotrochantericus caudalis significantly reduces torsional deformation of the proximal femur, protecting the vulnerable femoral neck from high fracture risk induced by rotation load. Given that the femur torsion during terrestrial locomotion in birds is associated with changes in hindlimb posture due to their adaptation to flight, the characteristics of M. iliotrochantericus caudalis may provide insight into the locomotor evolution of theropods and the origin of avian flight.

Predation is an important source of natural selection on prey species and has resulted in adaptations such as antipredator vocal signals, which can alert others to the presence of predators and solicit cooperative attack. Although vocal alarm signals of birds have been well studied, they are poorly known in tropical African species. To address this lack of information, the antipredatory signals and responses of two lapwings (Wattled Lapwing Vanellus senegallus and Spur-winged Lapwing Vanellus spinosus) to potential predators were investigated using data collected from focal observation, distance measurements, focal recordings, and playback experiment. The lapwing calls elicited to predators were classified as alarm or mobbing calls based on whether the calls elicited alert behavior or attack from other lapwings. Discriminant linear analysis (DLA) was used to compare the time and frequency parameters of the call types measured in Raven PRO. Also, lapwings’ responses to intruders, alert and start distance, time of day, and latency, as well as the effects of flock size and distance to cover were examined. About 48% of all calls was correctly classified by DLA. The best predictors of call type for the lapwings were maximum frequency and high frequency. Both alarm and mobbing calls were elicited by African Wattled Lapwings to dogs and humans. Mobbing calls were elicited to intruders by the Spur-winged Lapwings. Alert distance was positively associated with start distance, and differed between morning and evening in both lapwings. With scarce information from tropical Africa, this study put in perspective vocal and antipredator behavior of lapwing species in Africa.

Island ecosystems, serving as natural laboratories, facilitate geographical isolation, ecological specialization, and species divergence. The Sichuan Basin, surrounded by mountain ranges, represents a typical continental island due to its marked environmental spatial heterogeneity. This heterogeneity may contribute to geographical isolation and habitat heterogeneity, resulting in genetic divergence within populations. Therefore, we used the White-browed Laughingthrush (Garrulax sannio) as a model specimen to investigate the genetic divergence in the Sichuan Basin and its surrounding mountain ranges, given its presence in various habitats within and beyond this basin. Employing a RAD-seq dataset of 140 G. sannio individuals from 17 distinct ecological zones in the Sichuan Basin and its surrounding mountain ranges, we conducted PCA, population structure analysis, phylogenetic tree construction, and gene flow analysis to comprehensively analyze G. sannio groups. Additionally, in conjunction with geographical and ecological data, we performed isolation by distance, isolation by environment, PCA, and latent factor mixed model analysis to identify factors influencing the genetic divergence among these G. sannio groups. In summary, the 17 G. sannio groups were categorized into high-elevation, medium-elevation, and low-elevation groups. Genetic divergence in G. sannio may be attributed to both geographical distance and key ecological factors, particularly elevation and key climatic variables. Notably, the high-elevation group exhibited a greater number of SNPs and selected genes associated with the key ecological factors compared to the low-elevation group. The ADCY9 gene and several associated key pathways were identified as crucial elements driving ecological adaptation (elevation and key climatic variables) in the high-elevation group. Furthermore, climate changes during the glacial cycles may have facilitated gene flow among these groups residing in the Sichuan Basin and its surrounding mountain ranges. Our findings provide evidence of genetic divergence in G. sannio influenced by the geographical distance and key ecological factors between the Sichuan Basin and its surrounding mountain ranges. These results lay the groundwork for future research on the molecular systematics of continental islands.