The gastrointestinal microbiota played an important role in animal health by acting as a barrier against pathogens, exerting multiple metabolic functions and stimulating the development of the host immune system. To better understand the age-related dynamic changes in gut microbiota, we used 16S rRNA genes sequencing to investigate the cloacal microbial communities of the adult and chick bar-headed geese (Anser indicus). Fusobacteria, Firmicutes, Proteobacteria, Actinobacteria were the main components shared by adults and chicks. The former had more Proteobacteria and Cyanobacteria and the latter had more Fusobacteria and Actinobacteria. At the genus level, most of the dominant genera found in chicks were different from those in adults. In addition, adults had richer and more diverse bacterial communities than chicks. Our analysis of the composition of cloacal microbiota at the OTUs level also showed very large overlap existed in the bacterial assemblages between chicks and adults. These overlapped microbes were considered as the major microbes in the gastrointestinal tracts of bar-headed geese throughout their whole life span. Taken together, the results of this study provided a first inventory of the gut microbiotas of chick bar-headed geese and represented a first step in a wider investigation of the sequential changes in gut microbiotas with ages in bar-headed geese. [ABSTRACT FROM AUTHOR]