Understanding the Prevalence of Plumage Microbes in Australia

Students: Nadya Sotnychuk and Larynn Cutshaw
Mentor: Laura Tuhela-Reuning (Department of Botany-Microbiology)

We traveled to Victoria, Australia in the summer of 2015 to collect bacterial and feather samples from 26 species and 279 individual birds. We were looking for Bacillus spp. which are a bacterial group capable of degrading feathers. We found that all 26 species captured and 87.46% individuals sampled had at least one colony of Bacillus. This research is the first report of Bacillus on living Australian bird plumage in the wild.

The microbial ecosystem in plumage includes bacteria that degrade keratin in feathers. The prevalence and diversity of these microbes vary geographically and by foraging type in the United States. However, little is known about plumage microbes of Australian birds. To investigate keratinolytic bacteria outside the U.S., feathers were sampled from 279 birds of 26 species in 10 different locations within a 170 km radius of Deakin University (Geelong Waurn Ponds Campus) in Victoria, Australia. Birds were sampled using contact plates of Tryptic Soy Agar, Mannitol Salt Agar, Eosin Methylene Blue Agar, and Yeast Mold Agar. Following inoculation, colonies were counted and classified by morphology with special attention given to those that appeared to be Bacillus licheniformis, Bacillus cereus, Bacillus subtilis, and Staphylococcus, as these are potential keratinolytic species. Presumed Bacillus spp. were identified on all 26 species captured and 87.46% individuals sampled. Bacillus was found on all sixteen of the White-browed Scrubwrens (Sericornis frontalis), a forest floor dweller, sampled. These findings are consistent with previous studies that found ground and arboreal foragers had higher loads of Bacillus than aerial foragers due to the soil dwelling nature of Bacillus spp. This research is the first report of Bacillus on Australian bird plumage in vivo.