Understanding the mechanisms underlying seasonal community dynamics is important for predicting biodiversity responses to environmental fluctuations, enhancing ecological forecasting, and informing conservation strategies. In this study, we use standard transect and mist netting methods investigated seasonal altitudinal migration patterns of montane bird species in the Gyirong Valley, Central Himalayas. Our results showed four distinct altitudinal migration patterns among montane bird species: no shift, downslope shift, upslope shift, and contraction to mid-elevation zones. Species with smaller body weight and higher ratios of wing length, tail length, and tarsus length to body weight tended to migrate to lower elevations. Insectivorous birds exhibited a collective downslope shift, while omnivorous birds showed a wider range of migratory responses to seasonal variation. Migratory behavior was found to dynamically modulate the association between phenotypic traits and habitat preferences. During the breeding season, species (70.44%) and functional turnover (80.02%) dominated, while in the non-breeding season, nestedness significantly contributed to species (49.37%) and functional diversity (38.09%). In addition, migration can disrupt the direct influence of environmental variables on biodiversity patterns, providing important insights for montane biodiversity conservation under climate change. Our results highlight the critical need to safeguard low-elevation winter habitats and create dynamic protected areas to aid bird conservation amidst climate change.

Diet, morphological traits, and other ecological characteristics may influence the composition of bird communities. The southern slopes of the Himalayas are one of the global hotspots for avian species diversity. However, systematic research on the distribution patterns of birds in this region and the intrinsic links between these patterns and ecological characteristics has not yet been reported. This research gap limits our comprehensive understanding of the avian ecosystem in this area and affects the formulation of targeted conservation strategies. Using standard transect methods and mist-netting, we surveyed bird species, their numbers, as well as the habitats in four 300 m elevation bands during the breeding season (May–June 2024) in the middle elevations of the Gyirong Valley, a typical valley on the southern slope of the Himalayas. We analyzed the bird species composition, habitat distribution, and the influence of ecological characteristics on bird distribution patterns using R 4.4. During the field survey of the breeding season in the middle elevations of the Gyirong Valley, a total of 76 bird species were recorded. Among them, birds from the families Muscicapidae and Phylloscopidae within the order Passeriformes constitute the dominant groups. Insectivorous and omnivorous birds were the main groups in the Gyirong Valley. Birds with different diets and morphological traits show distinct differentiation in habitat selection. The higher the specialization rate of ecological traits, the smaller the population size of the birds, and the more likely they are to become endangered species. Moreover, morphological traits significantly influenced the distribution patterns of birds in the middle elevations of the Gyirong Valley. Therefore, when formulating conservation strategies for birds in the Gyirong Valley, it is essential to fully consider the differences in habitat requirements for birds with different ecological traits.