show Abstracthide AbstractTits (Aves: Paridae), a passerine bird group, are originated in the Sino-Himalayan region, and widely distribute in Eurasia, tropical Africa, and North America. A highly disproportionate number of tits inhabits high-altitude ranges, the highest is up to 5,500 m. The altitudinal distribution provides an opportunity to investigate the evolution of tits and their adaptations to high-altitude environments on the Qinghai-Tibet Plateau.