The supplementary information provides extra details of methods used to record scold calls, creat... more The supplementary information provides extra details of methods used to record scold calls, create playback tracks and carry out playback experiments. It also includes extra information on the results (including the MCMCglmm analyses), a link to a video file illustrating a response to a playback with five individuals calling and extra information for the discussion. In addition, there are extra tables and plots to further aid understanding of the statistical analysis.
Collective responses to threats occur throughout the animal kingdom but little is known about the... more Collective responses to threats occur throughout the animal kingdom but little is known about the cognitive processes underpinning them. Antipredator mobbing is one such response. Approaching a predator may be highly risky, but the individual risk declines and the likelihood of repelling the predator increases in larger mobbing groups. The ability to appraise the number of conspecifics involved in a mobbing event could therefore facilitate strategic decisions about whether to join. Mobs are commonly initiated by recruitment calls, which may provide valuable information to guide decision-making. We tested whether the number of wild jackdaws responding to recruitment calls was influenced by the number of callers. As predicted, playbacks simulating three or five callers tended to recruit more individuals than playbacks of one caller. Recruitment also substantially increased if recruits themselves produced calls. These results suggest that jackdaws use individual vocal discrimination to assess the number of conspecifics involved in initiating mobbing events, and use this information to guide their responses. Our results show support for the use of numerical assessment in antipredator mobbing responses and highlight the need for a greater understanding of the cognitive processes involved in collective behaviour.
Strong selection pressures are known to act on animal colouration. Although many animals vary in ... more Strong selection pressures are known to act on animal colouration. Although many animals vary in eye colour, virtually no research has investigated the functional significance of these colour traits. Passeriformes have a range of iris colours, making them an ideal system to investigate how and why iris colour has evolved. Using phylogenetic comparative methods, we tested the hypothesis that conspicuous iris colour in passerine birds evolved in response to (i) coordination of offspring care and (b) cavity nesting, two traits thought to be involved in intra-specific gaze sensitivity. We found that iris colour and cooperative offspring care by two or more individuals evolved independently, suggesting that bright eyes are not important for coordinating parental care through eye gaze. Furthermore, we found that evolution between iris colour and nesting behaviour did occur in a dependent manner, but contrary to predictions, transitions to coloured eyes were not more frequent in cavity nesters than non-cavity nesters. Instead, our results indicate that selection away from having bright eyes was much stronger in non-cavity nesters than cavity nesters, perhaps because conspicuous eye colouration in species not concealed within a cavity would be more visible to predators.
Visitation data collected at feeding tables during 2014-2015 for an experiment on social cue usag... more Visitation data collected at feeding tables during 2014-2015 for an experiment on social cue usage in wild jackdaws. All analysis was based on this file. See README file for column descriptions.
Proceedings of The Royal Society B: Biological Sciences, Aug 9, 2023
Animal cultures have now been demonstrated experimentally in diverse taxa from flies to great ape... more Animal cultures have now been demonstrated experimentally in diverse taxa from flies to great apes. However, experiments commonly use tasks with unrestricted access to equal pay-offs and innovations seeded by demonstrators who are trained to exhibit strong preferences. Such conditions may not reflect those typically found in nature. For example, the learned preferences of natural innovators may be weaker, while competition for depleting resources can favour switching between strategies and generalizing from past experience. Here we show that in experiments where wild jackdaws ( Corvus monedula ) can freely discover depleting supplies of novel foods, generalization has a powerful effect on learning, allowing individuals to exploit multiple new opportunities through both social and individual learning. Further, in contrast to studies with trained demonstrators, individuals that were first to innovate showed weak preferences. As a consequence, many individuals ate all available novel foods, displaying no strong preference and no group-level culture emerged. Individuals followed a ‘learn from adults’ strategy, but other demographic factors played a minimal role in shaping social transmission. These results demonstrate the importance of generalization in allowing animals to exploit new opportunities and highlight how natural competitive dynamics may impede the formation of culture.
Journal of the Royal Society Interface, Apr 1, 2022
Collective behaviour can be difficult to discern because it is not limited to animal aggregations... more Collective behaviour can be difficult to discern because it is not limited to animal aggregations such as flocks of birds and schools of fish wherein individuals spontaneously move in the same way despite the absence of leadership. Insect swarms are, for example, a form of collective behaviour, albeit one lacking the global order seen in bird flocks and fish schools. Their collective behaviour is evident in their emergent macroscopic properties. These properties are predicted by close relatives of Okubo's 1986 [ Adv. Biophys. 22 , 1–94. ( doi:10.1016/0065-227X(86)90003-1 )] stochastic model. Here, we argue that Okubo's stochastic model also encapsulates the cohesiveness mechanism at play in bird flocks, namely the fact that birds within a flock behave on average as if they are trapped in an elastic potential well. That is, each bird effectively behaves as if it is bound to the flock by a force that on average increases linearly as the distance from the flock centre increases. We uncover this key, but until now overlooked, feature of flocking in empirical data. This gives us a means of identifying what makes a given system collective. We show how the model can be extended to account for intrinsic velocity correlations and differentiated social relationships.
This is the author accepted manuscript.DEFINITION: When two or more distantly related species evo... more This is the author accepted manuscript.DEFINITION: When two or more distantly related species evolve similar cognitive adaptations in response to comparable environmental challenges
The adjustment of social associations by individuals in response to changes in their social envir... more The adjustment of social associations by individuals in response to changes in their social environment is a core principle of influential theories on the evolution of cognition1,2 and cooperation3,4. Selectively adjusting associations with others is thought to allow individuals to maximise short-term rewards from social interactions, thus re-shaping social networks to better favour connections between compatible group members5–8. Crucially, this has yet to be tested in natural populations, where the need to maintain long-term, fitness-enhancing relationships may limit social plasticity9,10. Using a novel social-network-manipulation experiment, we show that wild jackdaws (Corvus monedula) learned to favour social associations with compatible group members (individuals that provided greater returns from social foraging interactions). Consequently, the overall frequency of associations between compatible social partners increased as the experiment progressed. This resulted in clusteri...
Original images captured by one of the four cameras and the reconstructed birds’ 3D movement traj... more Original images captured by one of the four cameras and the reconstructed birds’ 3D movement trajectories for flock #6
Detailed methods and supplementary figures for the article "Social learning about dangerous ... more Detailed methods and supplementary figures for the article "Social learning about dangerous people by wild jackdaws", Lee et al. (2019)
The supplementary information provides extra details of methods used to record scold calls, creat... more The supplementary information provides extra details of methods used to record scold calls, create playback tracks and carry out playback experiments. It also includes extra information on the results (including the MCMCglmm analyses), a link to a video file illustrating a response to a playback with five individuals calling and extra information for the discussion. In addition, there are extra tables and plots to further aid understanding of the statistical analysis.
Collective responses to threats occur throughout the animal kingdom but little is known about the... more Collective responses to threats occur throughout the animal kingdom but little is known about the cognitive processes underpinning them. Antipredator mobbing is one such response. Approaching a predator may be highly risky, but the individual risk declines and the likelihood of repelling the predator increases in larger mobbing groups. The ability to appraise the number of conspecifics involved in a mobbing event could therefore facilitate strategic decisions about whether to join. Mobs are commonly initiated by recruitment calls, which may provide valuable information to guide decision-making. We tested whether the number of wild jackdaws responding to recruitment calls was influenced by the number of callers. As predicted, playbacks simulating three or five callers tended to recruit more individuals than playbacks of one caller. Recruitment also substantially increased if recruits themselves produced calls. These results suggest that jackdaws use individual vocal discrimination to assess the number of conspecifics involved in initiating mobbing events, and use this information to guide their responses. Our results show support for the use of numerical assessment in antipredator mobbing responses and highlight the need for a greater understanding of the cognitive processes involved in collective behaviour.
Strong selection pressures are known to act on animal colouration. Although many animals vary in ... more Strong selection pressures are known to act on animal colouration. Although many animals vary in eye colour, virtually no research has investigated the functional significance of these colour traits. Passeriformes have a range of iris colours, making them an ideal system to investigate how and why iris colour has evolved. Using phylogenetic comparative methods, we tested the hypothesis that conspicuous iris colour in passerine birds evolved in response to (i) coordination of offspring care and (b) cavity nesting, two traits thought to be involved in intra-specific gaze sensitivity. We found that iris colour and cooperative offspring care by two or more individuals evolved independently, suggesting that bright eyes are not important for coordinating parental care through eye gaze. Furthermore, we found that evolution between iris colour and nesting behaviour did occur in a dependent manner, but contrary to predictions, transitions to coloured eyes were not more frequent in cavity nesters than non-cavity nesters. Instead, our results indicate that selection away from having bright eyes was much stronger in non-cavity nesters than cavity nesters, perhaps because conspicuous eye colouration in species not concealed within a cavity would be more visible to predators.
Visitation data collected at feeding tables during 2014-2015 for an experiment on social cue usag... more Visitation data collected at feeding tables during 2014-2015 for an experiment on social cue usage in wild jackdaws. All analysis was based on this file. See README file for column descriptions.
Proceedings of The Royal Society B: Biological Sciences, Aug 9, 2023
Animal cultures have now been demonstrated experimentally in diverse taxa from flies to great ape... more Animal cultures have now been demonstrated experimentally in diverse taxa from flies to great apes. However, experiments commonly use tasks with unrestricted access to equal pay-offs and innovations seeded by demonstrators who are trained to exhibit strong preferences. Such conditions may not reflect those typically found in nature. For example, the learned preferences of natural innovators may be weaker, while competition for depleting resources can favour switching between strategies and generalizing from past experience. Here we show that in experiments where wild jackdaws ( Corvus monedula ) can freely discover depleting supplies of novel foods, generalization has a powerful effect on learning, allowing individuals to exploit multiple new opportunities through both social and individual learning. Further, in contrast to studies with trained demonstrators, individuals that were first to innovate showed weak preferences. As a consequence, many individuals ate all available novel foods, displaying no strong preference and no group-level culture emerged. Individuals followed a ‘learn from adults’ strategy, but other demographic factors played a minimal role in shaping social transmission. These results demonstrate the importance of generalization in allowing animals to exploit new opportunities and highlight how natural competitive dynamics may impede the formation of culture.
Journal of the Royal Society Interface, Apr 1, 2022
Collective behaviour can be difficult to discern because it is not limited to animal aggregations... more Collective behaviour can be difficult to discern because it is not limited to animal aggregations such as flocks of birds and schools of fish wherein individuals spontaneously move in the same way despite the absence of leadership. Insect swarms are, for example, a form of collective behaviour, albeit one lacking the global order seen in bird flocks and fish schools. Their collective behaviour is evident in their emergent macroscopic properties. These properties are predicted by close relatives of Okubo's 1986 [ Adv. Biophys. 22 , 1–94. ( doi:10.1016/0065-227X(86)90003-1 )] stochastic model. Here, we argue that Okubo's stochastic model also encapsulates the cohesiveness mechanism at play in bird flocks, namely the fact that birds within a flock behave on average as if they are trapped in an elastic potential well. That is, each bird effectively behaves as if it is bound to the flock by a force that on average increases linearly as the distance from the flock centre increases. We uncover this key, but until now overlooked, feature of flocking in empirical data. This gives us a means of identifying what makes a given system collective. We show how the model can be extended to account for intrinsic velocity correlations and differentiated social relationships.
This is the author accepted manuscript.DEFINITION: When two or more distantly related species evo... more This is the author accepted manuscript.DEFINITION: When two or more distantly related species evolve similar cognitive adaptations in response to comparable environmental challenges
The adjustment of social associations by individuals in response to changes in their social envir... more The adjustment of social associations by individuals in response to changes in their social environment is a core principle of influential theories on the evolution of cognition1,2 and cooperation3,4. Selectively adjusting associations with others is thought to allow individuals to maximise short-term rewards from social interactions, thus re-shaping social networks to better favour connections between compatible group members5–8. Crucially, this has yet to be tested in natural populations, where the need to maintain long-term, fitness-enhancing relationships may limit social plasticity9,10. Using a novel social-network-manipulation experiment, we show that wild jackdaws (Corvus monedula) learned to favour social associations with compatible group members (individuals that provided greater returns from social foraging interactions). Consequently, the overall frequency of associations between compatible social partners increased as the experiment progressed. This resulted in clusteri...
Original images captured by one of the four cameras and the reconstructed birds’ 3D movement traj... more Original images captured by one of the four cameras and the reconstructed birds’ 3D movement trajectories for flock #6
Detailed methods and supplementary figures for the article "Social learning about dangerous ... more Detailed methods and supplementary figures for the article "Social learning about dangerous people by wild jackdaws", Lee et al. (2019)
Uploads
Papers by Alex Thornton