Pheromones in birds: myth or reality?

Abstract

Birds are anosmic or at best microsmatic… This misbelief persisted until very recently and has strongly influenced the outcome of communication studies in birds, with olfaction remaining neglected as compared to acoustic and visual channels. However, there is now clear empirical evidence showing that olfaction is perfectly functional in birds and birds use olfactory information in a variety of ethological contexts. Although the existence of pheromones has never been formally demonstrated in this vertebrate class, different groups of birds, such as petrels, auklets and ducks have been shown to produce specific scents that could play a significant role in within-species social interactions. Behavioral experiments have indeed demonstrated that these odors influence the behavior of conspecifics. Additionally, in quail, deprivation of olfactory inputs decreases neuronal activation induced by sexual interactions with a female. It seems therefore well established that birds enjoy a functional sense of smell and a fast growing body of experimental evidence suggests that they use this channel of olfactory communication to control their social life. The unequivocal identification of an avian pheromone is, however, still ahead of us but there are now many exciting opportunities to unravel the behavioral and physiological particularities of chemical communication in birds.

Evolution of olfaction in non-avian theropod dinosaurs and birds

“…In comparison, changes in olfaction (i.e. sense of smell) have received limited attention, which may be due, in part, to the preconceived notion that olfaction was a declining sensory modality during bird evolution [18][19][20][21] and to the historical misconception that birds have a poor sense of smell [22]. Birds are now known to have a wide range of olfactory capabilities, which are used for a variety of purposes, such as foraging, orientation and social interactions [22][23][24].…”

Smelling Out Predators is Innate in Birds

“…Nowadays, it has been shown that olfaction may be a more important sense in birds than was traditionally believed (Steiger et al 2008). Recent evidence suggests that birds can use odours in several ecological contexts and with different functions (Roper 1999, Hagelin 2007, Hagelin & Jones 2007, Rajchard 2007, 2008, Balthazart & Taziaux 2009, Caro & Balthazart 2010. At the intra-specific level, they are known to emit chemical compounds, which are important in several aspects of avian life histories (Caro & Balthazart 2010).…”

“…Recent evidence suggests that birds can use odours in several ecological contexts and with different functions (Roper 1999, Hagelin 2007, Hagelin & Jones 2007, Rajchard 2007, 2008, Balthazart & Taziaux 2009, Caro & Balthazart 2010. At the intra-specific level, they are known to emit chemical compounds, which are important in several aspects of avian life histories (Caro & Balthazart 2010). For example, birds can recognize their nest using chemical cues (Mínguez 1997, O'Dwyer et al 2008, Bonadonna & Bretagnolle 2002, Bonadonna et al 2003a,b, 2004, de León et al 2003, Caspers & Krause 2011 and they are able to discriminate the scent of their partners from the scent of other conspecifics (Bonadonna & Nevitt 2004, Jouventin et al 2007.…”

The importance of chemical communication studies to mammalian conservation biology: A review

“…Identifying cues that influence animal distribution and habitat selection enable decisions to be made on area protection, encouraging population, community and landscape conservation. Although this review addressed mammals a growing body of evidence indicates that birds not only possess but utilise a functional, and in some cases highly developed olfactory system (see Caro and Balthazart, 2010 We also thank three anonymous referees for their constructive feed back in shaping this manuscript.…”