Exogenous chemical substances in bird perception: a review

Abstract

The perception of exogenous chemical substances, olfactory navigation and the use of the olfactory sense by birds to search for food are reviewed. Many results suggest that the olfactory sense is one of the important components of the navigation system in birds. The olfactory mechanisms used by homing pigeons to navigate homeward from distant sites have been well studied. The scent of potential food, carcasses, is a positive attracting percept for Vultures. Procellariiform seabirds (petrels, albatrosses and shearwaters) are able to localize food sources by using their olfactory sense. Procellariforms are sensitive to scented compounds associated with their primary prey: krill-related odors (pyrazines and trimethylamine), odors associated with phytoplankton (dimethyl sulfide – DMS) and ammonia. Anting is a specific type of behavior of over 200 bird species. Birds probably use anting to control ectoparasites, inhibit the growth of fungi or bacteria, to soothe skin irritated during the molting period, and to remove toxic formic acid from ants prior to their consumption. Insectivorous birds react to insect malodorous substances, produced by insect groups as a chemical defense against predators.