Crested Auklets are arctic seabirds that use smell for social functions. This wouldn't exactly be news for any other group of animals, but it is a first for birds ─ those feathered creatures which can both smell and be smelly. These particular monogamous birds have a species-specific tangerine-like odor that attracts their mates. The question arises, where do the chemicals responsible for this scent (mainly cis-4-decenal and octanal) come from?
A recent study proposes that the origin of these attractants may well be the cleavage of long-chain fatty acids by bacteria. The microbial assemblages on the feathers of these animals are quite distinctive, as judged by culture-independent molecular techniques. Two genera, Psychrobacter and Paenibacillus, were found on auklet feathers but not on bluebirds, finches, or chickens. Psychrobacter makes special sense, being both cold and salt tolerant. Interestingly, Psychrobacter was not found on the closely-related Least Auklet which lacks the tangerine-like scent. Further work is needed to confirm the possible contribution of bacteria to the sex life of these attractive birds.