Sampling effort
A total of 123 breeding birds were recorded in our field surveys (Figure 2). All accumulation curves for each 100‐m elevational band reached a plateau or an asymptote (Figure S1 in Appendix 2). Moreover, the observed species richness was highly correlated with Chao2 value (R =0.82). Both accumulation curves and correlation analysis indicated that the sampling effort within 26 elevational bands was adequate.