Visual and auditory signals have been well studied in songbirds and often play important roles in premating reproductive isolation, but olfaction has received much less attention. Alex’s new paper shows that olfactory cues also have the potential to act in premating reproductive isolation. He found that preen oils from black-capped and Carolina chickadees have different chemical profiles, and that males and females of both species prefer to associate with odors from individuals of their own species. Check out his paper here!