Habitat shapes diversity of gut microbiomes in a wild population of blue tits Cyanistes caeruleus

Microbiome constitutes and important axis of individual variation that, together with genes and the environment, influences an individual’s physiology and fitness. Microbiomes are dependent not only on an individual’s body condition but also on external factors, such as diet or stress levels, and as such can be involved into feedbacks between the external ecological factors and internal physiology. In our study we used a wild population of blue tits (Cyanistes caeruleus) to investigate the impact of external habitat composition on the microbiome of adult birds. We hypothesized, that – through differences in plant composition, potentially affecting diet complexity – habitat type may impact the diversity and structure of the gut microbiome. Blue tits breeding in dense deciduous forests tended to have more diverse microbiomes, and significantly different in terms of microbiome composition from birds breeding in open, sparsely forested hay meadows. Distinct study plots also tended to differ...