Do Zebra Finch Parents Fail to Recognise Their Own Offspring?

Individual recognition systems require the sender to be individually distinctive and the receiver to be able to perceive differences between individuals and react accordingly. Many studies have demonstrated that acoustic signals of almost any species contain individualized information. However, fewer studies have tested experimentally if those signals are used for individual recognition by potential receivers. While laboratory studies using zebra finches have shown that fledglings recognize their parents by their “distance call”, mutual recognition using the same call type has not been demonstrated yet. In a laboratory study with zebra finches, we first quantified between-individual acoustic variation in distance calls of fledglings. In a second step, we tested recognition of fledgling calls by parents using playback experiments. With a discriminant function analysis, we show that individuals are highly distinctive and most measured parameters show very high potential to encode for individuality. The response pattern of zebra finch parents shows that they do react to calls of fledglings, however they do not distinguish between own and unfamiliar offspring, despite individual distinctiveness. This finding is interesting in light of the observation of a high percentage of misdirected feedings in our communal breeding aviaries. Our results demonstrate the importance of adopting a receiver's perspective and suggest that variation in fledgling contact calls might not be used in individual recognition of offspring

The importance of the altricial – precocial spectrum for social complexity in mammals and birds:A review

Various types of long-term stable relationships that individuals uphold, including cooperation and competition between group members, define social complexity in vertebrates. Numerous life history, physiological and cognitive traits have been shown to affect, or to be affected by, such social relationships. As such, differences in developmental modes, i.e. the ‘altricial-precocial’ spectrum, may play an important role in understanding the interspecific variation in occurrence of social interactions, but to what extent this is the case is unclear because the role of the developmental mode has not been studied directly in across-species studies of sociality. In other words, although there are studies on the effects of developmental mode on brain size, on the effects of brain size on cognition, and on the effects of cognition on social complexity, there are no studies directly investigating the link between developmental mode and social complexity. This is surprising because developmental differences play a significant role in the evolution of, for example, brain size, which is in turn considered an essential building block with respect to social complexity. Here, we compiled an overview of studies on various aspects of the complexity of social systems in altricial and precocial mammals and birds. Although systematic studies are scarce and do not allow for a quantitative comparison, we show that several forms of social relationships and cognitive abilities occur in species along the entire developmental spectrum. Based on the existing evidence it seems that differences in developmental modes play a minor role in whether or not individuals or species are able to meet the cognitive capabilities and requirements for maintaining complex social relationships. Given the scarcity of comparative studies and potential subtle differences, however, we suggest that future studies should consider developmental differences to determine whether our finding is general or whether some of the vast variation in social complexity across species can be explained by developmental mode. This would allow a more detailed assessment of the relative importance of developmental mode in the evolution of vertebrate social systems

Begging calls support offspring individual identity and recognition by zebra finch parents.

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Begging calls support offspring individual identity and recognition by zebra finch parents.

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A murmuration of starlings: reduced vocal diversity in more populous groups?

International audienceSocial evolution and vocal evolution may be strongly linked. The starlings are songbirdsknown for their complex song repertoires and learning abilities. In the Red-winged Starling(Onychognathus morio), variation in social organisation (territorial to more colonial breeding)allows an assessment of the influence of social factors on vocal communication within asingle species. We compared the whistle characteristics among three populations withdifferent breeding associations in the Eastern Cape, South Africa. During one breedingseason, we recorded five widely-separated (>1 km apart) territorial pairs breeding in isolatedmountains, eight territorial pairs at higher density on a university campus (<100 m apart) andtwo dense colonies on cliffs with nests <10 m apart. Our results show that each isolatedterritorial pair had a large vocal repertoire and produced its own vocal themes. Conversely, asthe number of social partners increased, vocal sharing increased and the repertoire size wasreduced. The influence of habitat type and genetic differences between populations on vocalvariations was also investigated; the presence of more social partners seemed to be the keyfactor inducing greater uniformity in vocalisations. In social groups, individuals in regularcontact need to use the same channel of communication to regulate their interactions. Thereare interesting parallels with the evolution of language

Geographical variation in red-winged starling whistles

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Social shaping of voices does not impair phenotype matching of kinship in mandrills

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