Pied Babbler Research Project

Kuruman, South Africa

Pied Babbler Research Project

Kuruman, South Africa
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Engesser S.,University of Zürich | Engesser S.,Pied Babbler Research Project | Ridley A.R.,Pied Babbler Research Project | Ridley A.R.,University of Western Australia | And 4 more authors.
Animal Cognition | Year: 2017

Human language is a recombinant system that achieves its productivity through the combination of a limited set of sounds. Research investigating the evolutionary origin of this generative capacity has generally focused on the capacity of non-human animals to combine different types of discrete sounds to encode new meaning, with less emphasis on meaning-differentiating mechanisms achieved through potentially simpler temporal modifications within a sequence of repeated sounds. Here we show that pied babblers (Turdoides bicolor) generate two functionally distinct vocalisations composed of the same sound type, which can only be distinguished by the number of repeated elements. Specifically, babblers produce extended ‘purrs’ composed of, on average, around 17 element repetitions when drawing young offspring to a food source and truncated ‘clucks’ composed of a fixed number of 2–3 elements when collectively mediating imminent changes in foraging site. We propose that meaning-differentiating temporal structuring might be a much more widespread combinatorial mechanism than currently recognised and is likely of particular value for species with limited vocal repertoires in order to increase their communicative output. © 2017 Springer-Verlag GmbH Germany

Humphries D.J.,Macquarie University | Humphries D.J.,Pied Babbler Research Project | Finch F.M.,Pied Babbler Research Project | Bell M.B.V.,University of Edinburgh | And 5 more authors.
PLoS ONE | Year: 2015

For territorial group-living species, opportunities to reproduce on the natal territory can be limited by a number of factors including the availability of resources within a territory, access to unrelated individuals, and monopolies on reproduction by dominant group members. Individuals looking to reproduce are therefore faced with the options of either waiting for a breeding opportunity to arise in the natal territory, or searching for reproductive opportunities in non-natal groups. In the cooperatively breeding Southern pied babbler, Turdoides bicolor, most individuals who achieve reproductive success do so through taking up dominant breeding positions within non-natal groups. For subordinate pied babblers therefore, searching for breeding opportunities in non-natal groups is of primary importance as this represents the major route to reproductive success. However, prospecting (where individuals leave the group to search for reproductive opportunities within other groups) is costly and individuals rapidly lose weight when not part of a group. Here we demonstrate that subordinate pied babblers adopt an alternative strategy for mate attraction by vocal advertisement from within their natal territories. We show that subordinates focus their calling efforts on the edges of their territory, and specifically near boundaries with neighbouring groups that have potential breeding partners (unrelated individuals of the opposite sex). In contrast to prospecting, calling individuals showed no body mass loss associated with this behaviour, suggesting that calling from within the group may provide a 'cheap' advertisement strategy. Additionally, we show that subordinates use information regarding the composition of neighbouring groups to target the greatest number of potential mating partners. © 2015 Humphries et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Humphries D.J.,Macquarie University | Humphries D.J.,Pied Babbler Research Project | Finch F.M.,Pied Babbler Research Project | Bell M.B.V.,Pied Babbler Research Project | And 5 more authors.
Ethology | Year: 2016

The ability to identify social partners can play a key role in the coordination of social behaviours in group-living animals. Coordinating social behaviours over long distances becomes problematic, as cues to identity are often limited to one or two sensory modalities. This limitation can often select for strong individuality in those cues used for long-distance communication. Pied babblers, Turdoides bicolor, produce a number of different types of 'loud calls' which are frequently used to signal to individuals beyond the range of visual or olfactory pathways of communication. Here, we show that three of these 'loud call' types, the v-shaped chatter, the double note ascending chatter and the atonal chatter, are each individually distinct. We hypothesise that individuality in the three loud call types tested here may represent a possible pathway to social recognition in this species that may have important consequences for social interactions. However, we also found that the atonal chatter was unstable between years suggesting that this particular call type may not be a reliable long-term indicator to identity which may affect long-term recognition in this species. © 2016 Blackwell Verlag GmbH.

Hollen L.I.,University of Bristol | Bell M.B.V.,University of Cambridge | Bell M.B.V.,University of Edinburgh | Russell A.,Pied Babbler Research Project | And 4 more authors.
PLoS ONE | Year: 2011

Efficient cooperation requires effective coordination of individual contributions to the cooperative behaviour. Most social birds and mammals involved in cooperation produce a range of vocalisations, which may be important in regulating both individual contributions and the combined group effort. Here we investigate the role of a specific call in regulating cooperative sentinel behaviour in pied babblers (Turdoides bicolor). 'Fast-rate chuck' calls are often given by sentinels as they finish guard bouts and may potentially coordinate the rotation of individuals as sentinels, minimising time without a sentinel, or may signal the presence or absence of predators, regulating the onset of the subsequent sentinel bout. We ask (i) when fast-rate chuck calls are given and (ii) what effect they have on the interval between sentinel bouts. Contrary to expectation, we find little evidence that these calls are involved in regulating the pied babbler sentinel system: observations revealed that their utterance is influenced only marginally by wind conditions and not at all by habitat, while observations and experimental playback showed that the giving of these calls has no effect on inter-bout interval. We conclude that pied babblers do not seem to call at the end of a sentinel bout to maximise the efficiency of this cooperative act, but may use vocalisations at this stage to influence more individually driven behaviours. © 2011 Hollén et al.

Hollen L.I.,University of Bristol | Bell M.B.V.,University of Cambridge | Wade H.M.,Pied Babbler Research Project | Rose R.,Pied Babbler Research Project | And 4 more authors.
Animal Behaviour | Year: 2011

Ecological conditions can influence decisions relating to antipredator behaviour through impacts on the likelihood of detecting predators and the ability to hear vocalizations. Previous studies of antipredator behaviour have tended to focus on foragers, whose vigilance behaviour may be confounded by the type of food they are eating, and on receivers in vocal communication networks. We examined the impact of habitat and wind conditions on the behaviour of sentinels, individuals that suspend their own foraging to adopt a raised position to scan for danger while groupmates continue feeding, and that produce a variety of calls used by foragers to adjust their antipredator behaviour. Sentinels of the pied babbler, Turdoides bicolor, a cooperatively breeding bird, started guarding sooner and guarded for longer in long grass compared to more open habitats, and also initiated sentinel bouts sooner in high wind, probably because of the increased predation risk in such circumstances. Sentinels also selected positions that were both lower and closer to the foraging group when it was windy, potentially improving transmission of vocal signals that are valuable to foragers. Our results demonstrate that sentinel behaviour can be influenced by extrinsic factors, as well as the intrinsic factors previously shown, and suggest that ecological variation may affect decisions bearing both selfish and cooperative benefits. © 2011 The Association for the Study of Animal Behaviour.

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