The gut microbiota of Black-necked cranes was studied to understand why it changes. Fecal samples were collected and analyzed using advanced sequencing technology. The most abundant bacteria in their gut were Proteobacteria, followed by Firmicutes and Bacteroidetes. These bacteria help break down cellulose in the cranes' diet. Proteobacteria, especially the genus Psychrobacter, were found in high levels, which is unusual in birds. This bacteria can grow in very cold temperatures. The study showed differences in the gut microbiota of the cranes at different times. Understanding these bacteria can help us learn more about how Black-necked cranes and other migratory waterbirds get energy and nutrients from their food.