Temporal dynamics of the fecal microbiome in wintering seagulls: a One Health perspective

Migratory birds serve as critical reservoirs for zoonotic pathogens, with transmission risks significantly amplified by anthropogenic activities such as recreational feeding. Despite their role in disseminating pathogens, the temporal dynamics of the gut microbiota in wintering seagulls under sustained human contact remain poorly characterized within a One Health framework. In this study, we conducted semi-monthly fecal sampling of black-headed gulls overwintering at a coastal tourism hotspot during consecutive wintering periods. Full-length 16S rRNA PacBio HiFi sequencing revealed remarkable microbial diversity and skewed distributions within the fecal communities. Although stochastic processes dominated microbial community assembly, temporal dynamics were observed as significant fluctuations in diversity indices, shifts in taxa prevalence, and episodic blooms of specific bacteria, reflecting signatures of foraging activities and anthropogenic interventions, particularly the provision of supplemental human food. Notably, 53 putative species-level pathogens were identified, with 11 of these exhibiting potential for cross-host transmission between migratory gulls and local inhabitants. Overall, this study provides a comprehensive One Health perspective on the gut microbiome of wintering migratory seagulls, offering valuable reference information for future wildlife management and public health protection.