Abstract
The breeding success of birds is crucial for their survival and development, with nest features and nest-site selection playing a significant role in the reproductive process. This study investigated the nest features of the giant babax, the key environmental factors influencing its nest-site selection, and the factors affecting its reproductive success. We conducted field research at four sample plots in Lhasa, Xizang, from March to October 2023. Examining a total of 34 nests, 26 (76.5%) were successful, while 8 (23.5%) failed. Principal component analysis (PCA) revealed that the primary environmental factors influencing nest-site selection of the giant babax were altitude, distance to water, distance to houses, canopy density, nesting tree height, and DBH. Binomial logistic regression analysis revealed that canopy density significantly influenced both nest-site selection and reproductive success. Additionally, the number of helpers had a significant effect on reproductive success.