The perfume of reproduction in birds: Chemosignaling in avian social life

Abstract

Chemical cues were probably the first cues ever used to communicate and are still ubiquitous among living organisms. Birds have long been considered an exception: it was believed that birds were anosmic and relied on their acute visual and acoustic capabilities. Birds are however excellent smellers and use odors in various contexts including food searching, orientation, but also breeding. Successful reproduction in most vertebrates involves the exchange of complex social signals between partners. The first evidence for a role of olfaction in reproductive contexts in birds only dates back to the seventies, when ducks were shown to require a functional sense of smell to express normal sexual behaviors. Nowadays, even if the interest for olfaction in birds has largely increased, the role that bodily odors play in reproduction still remains largely understudied. The few available studies however suggest that olfaction is involved in many reproductive stages. Odors have been shown to influence the choice and synchronization of partners, the choice of nest-building material or the care for the eggs and offspring. How this chemical information is translated at the physiological level mostly remain to be described, although available evidence suggests that, as in mammals, key reproductive brain areas like the medial preoptic nucleus are activated by relevant olfactory signals. Olfaction in birds receives increasing attention and novel findings are continuously published, but many exciting discoveries are still ahead of us, and could make birds one of the animal classes with the largest panel of developed senses ever described.

Sight or smell: which senses do scavenging raptors use to find food?

“…In summary, there is a distinct lack of behavioral studies designed to assess the olfactory abilities in diurnal raptors. It is important to understand whether raptors can functionally use their sense of smell for a specific function, such as foraging, navigation or communication, as already shown in other bird species (Nevitt et al 1995; Wallraff 2005; Caro et al 2015). …”

Conspecific olfactory preferences and interspecific divergence in odor cues in a chickadee hybrid zone

“…Chemical communication in particular has been shown to act as an important premating reproductive isolating barrier in a wide variety of animal taxa (Smadja & Butlin, 2009) including insects (Coyne, Crittenden, & Mah, 1994;Sasakawa & Kon, 2018), fish (Kodric-Brown & Strecker, 2001;Kozak, Head, & Boughman, 2011), reptiles (Barbosa, Font, Desfilis, & Carretero, 2006), amphibians (Dawley, 1984), and mammals (Johnston, 2003). However, conspecific preferences for interspecific odor cues have never been documented in a natural songbird hybrid zone (Caro, Balthazart, & Bonadonna, 2015).…”

Blue petrels recognize the odor of their egg

“…In the last decade, however, birds have been shown to use odor cues to communicate with their conspecifics (for review, see Caro et al, 2015). For instance, spotless starlings (Sturnus unicolor) recognize the sex of conspecifics by olfaction (Amo et al, 2012a), Antarctic prions (Pachyptila desolata) are attracted to their mate's odor (Bonadonna and Nevitt, 2004), and mallard (Anas platyrhynchos) and chicken (Gallus gallus domesticus) males with experimentally reduced olfaction have altered sexual behavior (Balthazart and Schoffeniels, 1979;Hirao et al, 2009).…”