Changes in protozoa (a) and helminth (b) diversity during the wintering period of the black-necked crane, Grus nigricollis. Differences in dietary Shannon, Simpson, and Chao1 indices among wintering periods. Values are presented as means ± sd. After a Kruskal–Wallis test, post hoc comparisons using the Dunn test with a Benjamini–Hochberg correction indicated a significant difference among wintering periods, as indicated by the different letters (p < 0.05).