Nest Microbial Community Dynamics Within the Nest-Building Stage of Green-Backed Tits (Parus monticolus)

The microbiota within bird nests is considered an important factor influencing the reproductive processes of birds. Certain pathogenic microorganisms present in nest environments may compromise avian health through direct infection of both adult birds and their offspring, ultimately leading to reduced reproductive success. However, there is a lack of systematic research on the changes in the microbial environment within the nest during the nest-building stages, where nest-building activities may exert a positive impact on the associated microbial communities. Here, diversity, microbial composition, and co-occurrence network in the nests of green-backed tits (Parus monticolus) during both pre- and post-nest-building stages were investigated using high-throughput sequencing technology coupled with microbial network analysis. We found that the nests had significant differences in the microbial communities between the pre- and post-nest-building stages of green-backed tits. The microbial community in the post-nest-building stage of green-backed tits was predominantly composed of beneficial bacteria, exhibiting an overall trend of increased abundance of beneficial microorganisms and decreased prevalence of pathogenic microorganisms. Furthermore, the complexity of the microbial co-occurrence networks decreased, whereas their stability was enhanced in the post-nest-building stage of green-backed tits. These findings highlight the impact of green-backed tits on the microbial community within the nest, revealing that the microecology becomes healthier and more stable during the post-nest-building stage of green-backed tits, and will help us gain a deeper understanding of the interactions between avian species and nest microbiota.