Abstract:The growth rate of wild Crested Ibis (Nipponia nippon) in the Shaanxi Hanzhong Crested Ibis National Nature Reserve before fledgling was measured in 2014 and 2015. The body growth indexes (body weight, body length, culmen length, tarsus length, wing length and middle toe length) of 15 nestlings from 6 nests were examined. The results showed that the growth of nestlings was not affected by the hatching order, and the growth rate of body length of male nestlings was faster than the female (Table 1). The growth curves of the nestlings matched with the Logistic models, and the growth rate of body weight reached the maximum at about 13-day-old (Table 2). Compared with the results from 1989, the overall nestling growth of the wild Crested Ibis slowed relatively (Table 2, 3; Fig. 1, 2), which could be explained by higher environmental pressure and lower food availability with the development of population size and their dispersal in recent decades.