Kent says finding out why there were variations in the level of contamination is probably the next step in the research. So far, there isn’t any reason to panic, Kent says. The microbes have likely been around as long as birds themselves, given their dependence on keratin—perhaps even longer. The impacts may also not all be bad. One potential benefit is that they cause bluebird feathers to shine brighter, allowing males that are covered in bacteria to sire more offspring.