Variation in Bird Gut Microbiota Across Dietary Guilds and Migratory Strategies.

Birds have a unique physiology, and their gut microbiota is regulated by ecological factors such as diet and migratory strategies. However, our understanding of how these factors drive the assembly and changes in the gut microbiota in birds is limited. We performed 16S rRNA sequencing of 61 bird cloacae samples. The results showed significant differences in the composition of the gut microbiota among birds with different ecological types (p < 0.05), and each taxonomic group (omnivory, carnivory, herbivory; migratory, or resident) had its core and unique ASVs (Amplicon Sequence Variants). Diet significantly altered the composition of the birds' gut microbiota, while migration strategy had a small but significant effect (p < 0.05). The dispersion in migratory birds was similar to that in resident birds, suggesting that migration does not increase the individual variability of bird gut microbiota. Overall, our findings reveal the associations between the avian gut microbiota and their diet or migration behavior.