Bacterial species richness at three stages of the breeding season in Cyanistes caeruleus (blue tit)

Blue tits are exposed to a vast array of bacteria throughout their life cycle and are particularly exposed during a breeding attempt. Any pathogenic bacteria within their microbiome can have a detrimental effect on their fitness and that of the nestlings they are raising. This study aims to identify the bacterial species richness that birds of this species are exposed to during three key stages of the breeding cycle: nest build, clutch completion and immediately post fledging. Nests were swabbed at these time points across four deciduous woodland sites in the United Kingdom and genomic DNA extracted prior to T-RFLP analysis. This is the first known instance of this technique being used to assess the nest microbiome and the first culture independent assessment of nest microbiome within this species. This revealed 103 distinct OTUs (Operational Taxonomic Units) across all sites and stages with an increase in taxa richness at each stage. There were differences in the microbiomes of each nest across breeding stage and site with evidence suggesting the nest microbiome is largely determined by the local environment.