Zebra Finch chicks recognise parental scent, and retain chemosensory knowledge of their genetic mother, even after egg cross-fostering

Abstract

Mechanisms underlying parent-offspring recognition in birds have fascinated researchers for centuries. Yet, the possibility that chicks recognise parental odour at hatching has been completely overlooked, despite the fact that olfaction is one of the first sensory modalities to develop, and social chemosignals occur in avian taxa. Here we show that Zebra Finch chicks (Taeniopygia guttata) are capable of identifying parental odours at hatching. In our first experiment, chicks begged significantly longer in response to the odour of their genetic mother or father compared to the odour of a non-relative of the same sex and reproductive status. In a second experiment, we cross-fostered eggs and tested the response of hatchlings to the scent of genetic vs. foster parents. Chicks from cross-fostered eggs responded significantly more to the odour of their genetic mother than their foster mother, but exhibited no difference in response to genetic vs. foster fathers. This is the first evidence that embryonic altricial birds are capable of acquiring chemosensory knowledge of their parents during early development, and retain chemical familiarity with their genetic mother despite egg cross-fostering. Furthermore our data reveals that kin recognition in birds can develop without any association with a genetic parent at hatching.

Nestling tree swallows (Tachycineta bicolor) alter begging behaviour in response to odour of familiar adults, but not their nests

“…For the nest scent recognition experiment, we tested nestlings at 1 day of age and found no difference in response between orange scent and water, whereas for the parent scent recognition experiment, we tested nestlings at 2 days of age and found a change in response depending on the scent type. Similar experiments on zebra finches performed on the day of hatch (Caspers et al, ) or 1 day after hatch (Caspers et al, ) found significant effects in response to odour type, while an experiment on blue tits, which also found significant effects in response to odour type, tested nestlings at 7 days post‐hatch (Rossi et al, ). As our experiment was the first such experiment on tree swallows, however, we cannot rule out that olfactory development may be slower in nestling tree swallows than zebra finches, and therefore, they may be more responsive to odour stimuli when they are older.…”

“…Second, odour recognition of parents may be an innate character, and cross‐fostering would be necessary to test this. In zebra finches, such an experiment showed that nestlings preferred the odour of their genetic, rather than foster, mother, but showed no preference between genetic and foster fathers (Caspers et al, ). In tree swallows, however, most broods contain extra‐pair young (O'Brien & Dawson, and references therein), so some nestlings may be genetically unrelated to the male that provides care.…”

“…For the parent scent recognition experiment, we followed the methods of Caspers et al (). Two days post‐hatch, adults were trapped in the nest box, banded, and either the male (“male scent boxes”; n = 10) or female (“female scent boxes”; n = 10) placed in a black nylon sock (68% nylon, 30% polyester, 2% spandex) for 30 min.…”

“…Cross‐fostering nestlings (Caspers & Krause, ) and eggs (Caspers, Hoffman, Kohlmeier, Krüger, & Krause, ) showed that nestlings learned the odour of their nest during a short time period around hatching. Nestling zebra finches also begged longer to odours of a familiar than unfamiliar adult (Caspers et al, ), whereas nestling blue tits ( Cyanistes caeruleus ) begged longer and more intensely to odours of unfamiliar than familiar nestlings (Rossi et al, ).…”

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

“…Olfactory information for songbirds is most likely carried in uropygial gland oils, which have been shown to possess species-specific chemical compositions (Soini, Whittaker, Wiesler, Ketterson, & Novotny, 2013). Recent work suggests a role for olfaction in many aspects of avian ecology (reviewed in Caro & Balthazart, 2012) including species discrimination (Bonnadonna & Mardon, 2010;Whittaker et al, 2011;Zhang, Du, & Zhang, 2013), sex discrimination (Amo et al, 2012;Soini et al, 2007;Whittaker et al, 2010;Zhang, Sun, & Zuo, 2009;Zhang, Wei, Zhang, & Yang, 2010), threat detection (Amo, Galván, Tomás, & Sanz, 2008;Amo, Visser, & Oers, 2011;Roth, Cox, & Lima, 2008), individual quality (Amo et al, 2012;Whittaker, Gerlach, Soini, Novotny, & Ketterson, 2013), aggression (Whittaker et al, 2018), nest recognition (Caspers, Hoffman, Kohlmeier, Krüger, & Krause, 2013;Golüke, Dörrenberg, Krause, & Caspers, 2016), and kin recognition (Bonadonna & Sanz-Aguilar, 2012;Caspers, Gagliardo, & Krause, 2015;Caspers et al, 2017;Coffin, Watters, & Mateo, 2011;Krause, Kruger, Kohlmeier, & Caspers, 2012). Still, whether conspecific preferences for divergent odor cues exist in natural songbird hybrid zones and therefore whether odor cues might function as a premating barrier in songbirds remain unknown (Campagna, Mardon, Celerier, & Bonadonna, 2011;Caro et al, 2015).…”