Gut Microbiota and Antibiotic Resistance Genes Variations Among Different Migration Stages in the White-tailed Eagle

This study investigated the seasonal dynamics of the gut microbiome and antibiotic resistance genes (ARGs) in the migratory white-tailed eagle (Haliaeetus albicilla) at Jingxin Wetland, a critical stopover site in Northeast China. We collected 29 fecal samples across three key phenological periods: southward migration (December 2021), wintering (February 2022), and northward migration (March 2022). Using metagenomic sequencing, we aimed to 1) characterize the composition of the gut microbiota and resistome in this apex predator, 2) compare their seasonal variations between migration and wintering stages, and 3) assess the potential role of migratory raptors in the cross-ecosystem dissemination of ARGs. Our findings reveal that the wintering period serves as a critical phase for the accumulation of a more diverse and abundant resistome, likely influenced by prolonged local environmental exposure and dietary shifts. This study provides novel insights into how seasonal behavior and habitat use shape the microbial ecology of migratory birds and underscores their significance in the environmental spread of antibiotic resistance.