Cloacal microbiota of barn swallows from Northern Italy

<p>Bird gut microbiota shows large variation among geographical populations of the same species – probably because, differently from mammals, gut microbiota of birds is largely affected by extrinsic factors such as diet and environmental conditions. We analysed the cloacal microbiota (CM) of 12 barn swallows (<i>Hirundo rustica</i>) from a colony in Northern Italy by high-throughput DNA sequencing of the 16S rRNA gene. The CMs, dominated by bacteria of the phyla Proteobacteria, Actinobacteria, Firmicutes and Bacteroidetes, did not significantly differ between adult females, adult males and fledglings. This first description of barn swallow CM in Italy, together with two previous studies from Europe, suggests that CMs of geographically different barn swallow populations are dominated by bacteria belonging to the same phyla but different genera. The intra-colony similarity of the CMs may be due to the exposure of individuals to the same local environmental conditions while on their breeding grounds.</p

Ecological features of feather microbiota in breeding common swifts

<p>We provide the first-ever investigation of feather microbiota by high throughput DNA sequencing for any bird species by describing bacteria found on the innermost tertial feather of 22 adult common swifts (<i>Apus apus</i>). We found feather microbiomes with large abundance of Bacillales, Actinomycetales, Burkholderiales, Sphingobacteriales, Sphingomonadales, Rhizobiales, Pseudomonadales, Clostridiales, Rubrobacterales and Lactobacillales. Bacterial communities did not change with any feature of individual swifts. Network and cluster analysis of feather microbiomes disclosed three clusters, characterized by bacteria typical of seawater, plants and soil and unrelated to conditions at the breeding grounds. We hypothesize that feather microbiomes reflect, at least partly, airborne bacterial communities of the environments where individuals spent non-breeding periods, or of those that they crossed during migration, rather than breeding environment. If confirmed, this evidence may disclose the possibility to use feather bacteria as proxies for tracing non-breeding origin and routes of migratory birds.</p