Environmental changes impact distribution range and population size of organisms. Most endemic species of Taiwan inhabit mid- and high-elevation areas. Under current trend of global warming, it is needed to monitor the altitudinal distribution and population size of these species. The objectives of this project were to investigate bird communities in historical sampling stations and routes, analyze bird watching records, and assess the vulnerability of the species in Yushan National Park. From March to October, 2014, we estimated densities of bird species in the 50 sampling stations of Ding (1993) and on the transect of Kuo (1986), with same sampling methods. We also analyzed the Bird Records Database of Chinese Wild Bird Federation (CWBF). Field investigations reveal significant changes in elevational distribution of some bird species. Among the 62 species recorded, 4 disappeared, 4 colonized, 21 significantly shifted upwards, 6 shifted downwards, and 3 expanded their distribution ranges. Historical trends of CWBF database were similar with field investigations. Vulnerability analyses showed bird species of mid- and high-elevation areas will face greater impacts of climatic changes and Yushan National Park is an important sanctuary for these species. We suggest YushanNational Park shall conduct monitor programs and priority of indicator species include: (first level) Alpine Accentor and Winter Wren; (second level) White-browed Shortwing, Taiwan Barwing, Taiwan Fulvetta, Taiwan Bush-Warbler, and Gray-headed Bullfinch; and (third level) White-browed Bush-Robin, Yellowish-bellied Bush-Warbler, Brown Bullfinch, and Taiwan Rosefinch.