Kin recognition and inbreeding avoidance in wild birds: the first evidence for individual kin-related odour recognition

Identification of family members plays a primary role in the evolution of social behaviours such as nepotism, altruism and mate choice. The process is particularly important for philopatric species in which the encounter rate of kin-related conspecifics is high. Olfactory-based recognition of individual kin has been identified in most species, with the exception of birds; historically, birds were thought to have poor olfactory abilities, so the use of olfactory cues was ruled out a priori. Here, we show that European storm petrels, Hydrobates pelagicus, are able to distinguish kin from nonkin odours. Using special cotton swabs, like those used in forensic police procedures, we offered birds a binary choice in a Y-maze. Birds significantly preferred odours of unrelated individuals. Olfactory imprinting on a ‘family olfactory template’ or self-referent phenotype matching may be the mechanism underlying this effect. This choice behaviour may allow these highly philopatric birds to avoid inbreeding and select an appropriate mate. Our results suggest that sophisticated olfactory communication is relevant in birds, and leads to important behavioural traits such as philopatry.