The Experts below are selected from a list of 789 Experts worldwide ranked by ideXlab platform
Alex Thornton - One of the best experts on this subject based on the ideXlab platform.
-
cooperative nest building in wild Jackdaw pairs
Animal Behaviour, 2021Co-Authors: Luca G Hahn, Guillam E Mcivor, Rebecca Hooper, Alex ThorntonAbstract:Animals create diverse structures, both individually and cooperatively, using materials from their environment. One striking example is the nests birds build for reproduction, which protect the offspring from external stressors such as predators and temperature, promoting reproductive success. To construct a nest successfully, birds need to make various decisions, for example regarding the nest material and their time budgets. Research has focused mainly on species where one sex is primarily responsible for building the nest. In contrast, the cooperative strategies of monogamous species in which both sexes contribute to nest building are poorly understood. Here we investigated the role of both sexes in nest building and fitness correlates of behaviour in wild, monogamous Jackdaw pairs, Corvus monedula. We show that both partners contributed to nest building and behaved similarly, with females and males present in the nestbox for a comparable duration and transporting material to the nest equally often. However, while females spent more time constructing the nest, males tended to invest more time in vigilance, potentially as a means of coping with competition for nest cavities. These findings suggest a moderate degree of division of labour, which may facilitate cooperation. Moreover, some aspects of behaviour were related to proxies of reproductive success (lay date and egg volume). Females that contributed relatively more to bringing material laid earlier clutches and pairs that spent less time together in the nestbox had larger eggs. Thus, selection pressures may act on how nest-building pairs spend their time and cooperatively divide the labour. We conclude that cooperative nest building in birds could be associated with monogamy and obligate biparental care and provides a vital but relatively untapped context through which to study the evolution of cooperation.
-
cooperative nest building in wild Jackdaw pairs
bioRxiv, 2020Co-Authors: Luca G Hahn, Guillam E Mcivor, Rebecca Hooper, Alex ThorntonAbstract:Animals create diverse structures, both individually and cooperatively, using materials from their environment. One striking example are the nests birds build for reproduction, which protect the offspring from external stressors such as predators and temperature, promoting reproductive success. To construct a nest successfully, birds need to make various decisions, for example regarding the nest material and their time budgets. To date, research has focused mainly on species where one sex is primarily responsible for building the nest. In contrast, the cooperative strategies of monogamous species in which both sexes contribute to nest building are poorly understood. Here we investigated the role of both sexes in nest building and fitness correlates of behaviour in wild, monogamous Jackdaw pairs (Corvus monedula). We show that both partners contributed to nest building and behaved similarly, with females and males present in the nest box for a comparable duration and transporting material to the nest equally often. However, while females spent more time constructing the nest, males tended to invest more time in vigilance, potentially as a means of coping with competition for nest cavities. These findings suggest a moderate degree of division of labour, which may facilitate cooperation. Moreover, some aspects of behaviour were related to proxies of reproductive success (lay date and egg volume). Females that contributed relatively more to bringing material laid earlier clutches and pairs that spent less time together in the nest box had larger eggs. Thus, selection pressures may act on how nest building pairs spend their time and cooperatively divide the labour. We conclude that cooperative nest building in birds could be associated with monogamy and obligate biparental care, and provides a vital but relatively untapped context through which to study the evolution of cooperation.
-
behavioural plasticity and the transition to order in Jackdaw flocks
Nature Communications, 2019Co-Authors: Alex Thornton, Hangjian Ling, Guillam E Mclvor, Joseph Westley, Kasper Van Der Vaart, Richard T Vaughan, Nicholas T OuelletteAbstract:Collective behaviour is typically thought to arise from individuals following fixed interaction rules. The possibility that interaction rules may change under different circumstances has thus only rarely been investigated. Here we show that local interactions in flocks of wild Jackdaws (Corvus monedula) vary drastically in different contexts, leading to distinct group-level properties. Jackdaws interact with a fixed number of neighbours (topological interactions) when traveling to roosts, but coordinate with neighbours based on spatial distance (metric interactions) during collective anti-predator mobbing events. Consequently, mobbing flocks exhibit a dramatic transition from disordered aggregations to ordered motion as group density increases, unlike transit flocks where order is independent of density. The relationship between group density and group order during this transition agrees well with a generic self-propelled particle model. Our results demonstrate plasticity in local interaction rules and have implications for both natural and artificial collective systems. Modelling collective behaviour in different circumstances remains a challenge because of uncertainty related to interaction rule changes. Here, the authors report plasticity in local interaction rules in flocks of wild Jackdaws with implications for both natural and artificial collective systems.
-
collective turns in Jackdaw flocks kinematics and information transfer
Journal of the Royal Society Interface, 2019Co-Authors: Alex Thornton, Hangjian Ling, Guillam E Mclvor, Joseph Westley, Kasper Van Der Vaart, Richard T Vaughan, Jennifer Yin, Nicholas T OuelletteAbstract:The rapid, cohesive turns of bird flocks are one of the most vivid examples of collective behaviour in nature, and have attracted much research. Three-dimensional imaging techniques now allow us to characterize the kinematics of turning and their group-level consequences in precise detail. We measured the kinematics of flocks of wild Jackdaws executing collective turns in two contexts: during transit to roosts and anti-predator mobbing. All flocks reduced their speed during turns, probably because of constraints on individual flight capability. Turn rates increased with the angle of the turn so that the time to complete turns remained constant. We also find that context may alter where turns are initiated in the flocks: for transit flocks in the absence of predators, initiators were located throughout the flocks, but for mobbing flocks with a fixed ground-based predator, they were always located at the front. Moreover, in some transit flocks, initiators were far apart from each other, potentially because of the existence of subgroups and variation in individual interaction ranges. Finally, we find that as the group size increased the information transfer speed initially increased, but rapidly saturated to a constant value. Our results highlight previously unrecognized complexity in turning kinematics and information transfer in social animals.
-
testing relationship recognition in wild Jackdaws corvus monedula
Scientific Reports, 2019Co-Authors: Guillam E Mcivor, Alex ThorntonAbstract:According to the social intelligence hypothesis, understanding the challenges faced by social animals is key to understanding the evolution of cognition. In structured social groups, recognising the relationships of others is often important for predicting the outcomes of interactions. Third-party relationship recognition has been widely investigated in primates, but studies of other species are limited. Furthermore, few studies test for third-party relationship recognition in the wild, where cognitive abilities are deployed in response to natural socio-ecological pressures. Here, we used playback experiments to investigate whether wild Jackdaws (Corvus monedula) track changes in their own relationships and the relationships of others. Females were presented with ‘infidelity simulations’: playbacks of their male partner copulating with a neighbouring female, and their male neighbour copulating with another female, against a congruent control. Our results showed substantial inter-individual variation in responses, but females did not respond more strongly to infidelity playbacks, indicating that Jackdaws may not attend and/or respond to relationship information in this experimental context. Our results highlight the need for further study of relationship recognition and other cognitive traits that facilitate group-living in the wild, particularly in non-primates and in a wider range of social systems.
Nicola S. Clayton - One of the best experts on this subject based on the ideXlab platform.
-
Research data supporting “Wild Jackdaws’ reproductive success and their offspring’s stress hormones are connected to provisioning rate and brood size, not to parental neophobia”
2016Co-Authors: Alison L. Greggor, Karen A. Spencer, Nicola S. Clayton, Alex ThorntonAbstract:This data consists of one text file that explains the data labels, and two csv files. One csv file was used to compute the consistency of neophobia, control, and feeding rate measures and their impact on Jackdaw fitness, the other was used to analyse the factors influencing blood CORT hormone levels. Neophobia scores, measures of reproductive success, and offspring stress hormone levels were collected from a wild population of breeding Jackdaws (Corvus monedula) in Madingley, Cambridgshire, UK in 2013. Neophobia was assessed at nest boxes based on birds’ latencies to return to their nest when a novel object was present. Reproductive success was determined by counting the number and body condition of chicks per nest. A measure of baseline and stress-induced corticosterone (CORT) was taken for each chick within a subset of nests. The csv files contain data used for the analyses supporting the related research article (Wild Jackdaws’ reproductive success and their offspring’s stress hormones are connected to provisioning rate and brood size, not to parental neophobia). Please see the main article for further discussion relating to the results generated from this data.
-
wild Jackdaws corvus monedula recognize individual humans and may respond to gaze direction with defensive behaviour
Animal Behaviour, 2015Co-Authors: Gabrielle L Davidson, Nicola S. Clayton, Alex ThorntonAbstract:Predator recognition is a prerequisite for antipredator behaviour. Although species level predator recognition is well documented, there is emerging evidence that some birds, including corvids, can differentiate between individual humans that pose different levels of threat. Other predator cues such as gaze direction may offer additional important information regarding the likelihood of an attack, but it is unknown whether wild animals can integrate information about the individual identity and gaze direction of a predator when perceiving threat levels. Here we measured wild Jackdaws' responses to human head orientation, directed towards or away from their nestbox containing chicks. To test whether aversive responses to gaze direction were integrated with information about human identity, the human presenting gaze cues wore one of two masks: a ‘threatening’ mask that had previously been worn when handling the Jackdaws' chicks and a ‘neutral mask’ that had previously been worn when walking by, but not disturbing the nest. Latency to return to the nestbox was significantly higher when the threatening mask rather than the neutral mask was worn, but it was not influenced by head direction. However, once a Jackdaw landed outside the nestbox, there was a nonsignificant trend for it to be quicker to enter the box when the human was gazing towards, rather than away from the box. These results indicate that wild Jackdaws can recognize different individual humans and thus differentiate between those wearing a threatening and a neutral mask, and respond defensively by guarding their chicks from potential threat. Jackdaws may integrate both predator identity and gaze cues; however, predation risk is primarily perceived through individual human recognition.
-
salient eyes deter conspecific nest intruders in wild Jackdaws corvus monedula
Biology Letters, 2014Co-Authors: Gabrielle L Davidson, Nicola S. Clayton, Alex ThorntonAbstract:Animals often respond fearfully when encountering eyes or eye-like shapes. Although gaze aversion has been documented in mammals when avoiding group-member conflict, the importance of eye coloration during interactions between conspecifics has yet to be examined in non-primate species. Jackdaws (Corvus monedula) have near-white irides, which are conspicuous against their dark feathers and visible when seen from outside the cavities where they nest. Because Jackdaws compete for nest sites, their conspicuous eyes may act as a warning signal to indicate that a nest is occupied and deter intrusions by conspecifics. We tested whether Jackdaws’ pale irides serve as a deterrent to prospecting conspecifics by comparing prospectors’ behaviour towards nest-boxes displaying images with bright eyes (BEs) only, a Jackdaw face with natural BEs, or a Jackdaw face with dark eyes. The Jackdaw face with BEs was most effective in deterring birds from making contact with nest-boxes, whereas both BE conditions reduced the amount of time Jackdaws spent in proximity to the image. We suggest BEs in Jackdaws may function to prevent conspecific competitors from approaching occupied nest sites.
-
rook but not Jackdaw post conflict third party affiliation reduces aggression for aggressors
Ethology, 2013Co-Authors: Corina J Logan, Ljerka Ostojic, Nicola S. ClaytonAbstract:Post-conflict (PC) affiliation refers to positive social interactions that occur after fights. Although this behavior has been widely studied, its functions are rarely tested. We examine a potential function of PC third-party affiliation (affiliation between former opponents and bystanders) in rooks and Jackdaws by investigating the hypothesis that conflicts lead to further aggression and that PC third-party affiliation increases to reduce such aggression. The results show that PC affiliation reduces PC aggression for rook aggressors who were less likely to receive aggression after conflicts when they were affiliating with another vs. when they were alone. The opposite result was found for victims of both species who received more aggression after conflicts, and this aggression was not reduced by the act of affiliating. Finally, for Jackdaw aggressors, the amount of aggression received after conflicts was not influenced by whether the individual was affiliating or alone, indicating that PC third-party affiliation may serve a function that we did not examine. These findings highlight the importance of investigating functional differences in PC affiliative behavior according to the role played in the conflict.
-
can Jackdaws corvus monedula select individuals based on their ability to help
Interaction Studies, 2011Co-Authors: Auguste Marie Philippa Von Bayern, Nicola S. Clayton, Nathan J. EmeryAbstract:Knowing the individual skills and competences of one's group members may be important for deciding from whom to learn (social learning), with whom to collaborate and whom to follow. We investigated whether 12 Jackdaws could select conspecifics based on their helping skills, which had been exhibited in a previous context. The birds were tested in a blocked-exit-situation, where they could choose between two conspecifics, one of which could be recruited inside. One conspecific had previously displayed the ability to open the exit door whilst the other individual lacked the skill. The subjects showed a significant preference for the skilled conspecific if they had previously directly benefited from this skill. If they had merely observed the skilled (and non-skilled) individual opening (or failing to open) the exit door, they did not preferably choose the skilled conspecific. Taken together, these results suggest that Jackdaws are capable of assessing other individuals' competence under certain circumstances.
Thomas Bugnyar - One of the best experts on this subject based on the ideXlab platform.
-
role of mental representations in quantity judgments by Jackdaws corvus monedula
Journal of Comparative Psychology, 2014Co-Authors: Dorottya Julia Ujfalussy, Thomas Bugnyar, Adam Miklosi, Kurt KotrschalAbstract:in similar ways. Considerable data also exist concerning such abilities in birds. Our aim in this study has been to find out whether Jackdaws (Corvus monedula) are capable of performing relative quantity judgments based on mental representations, and if so, what are the limiting factors to their abilities. In our setting the birds were required to make a choice between two visibly and sequentially placed set of food items which, at the moment of choice were not visible to the subjects. We investigated all the number combinations between 1 and 5. Our results show that Jackdaws are able to perform relative quantity judgments successfully, even when temporal cues are controlled for, whereas their performance declines in the direction of larger set size (numerical size effect), and when the difference between the two arrays decreases (numerical distance and ratio effect). These signatures are usually interpreted as evidence for the “accumulator” model of mental representation of quantity. Our control results suggest that Jackdaws do not use temporal cues, but may well use total volume as basis for discrimination, perhaps among other attributes (choice may be based on multiple cues).
-
ontogeny of object permanence in a non storing corvid species the Jackdaw corvus monedula
Animal Cognition, 2013Co-Authors: Dorottya Julia Ujfalussy, Adam Miklosi, Thomas BugnyarAbstract:The aim of the present study was to investigate the ontogeny of object permanence in a non-caching corvid species, the Jackdaw (Corvus monedula). Jackdaws are often presented as typical examples of non-storing corvids, as they cache either very little or not at all. We used Uzgiris and Hunt’s Scale 1 tasks to determine the age at which the certain stages set in and the final stage of this capacity that is reached. Our results show that the lack of food-storing behaviour is not associated with inferior object permanence abilities in the Jackdaw, as our subjects (N = 19) have reached stage 5 competence (to follow successive visible displacements) at the average age of 61 days post-hatch and showed some evidence of stage 6 competence (to follow advanced invisible displacements) at 81 days post-hatch and thereafter. As we appreciate that object permanence abilities have a very wide ecological significance, our positive results are probably the consequence of other, more fundamental ecological pressures, such as nest-hole reproduction or prey–predator interactions.
-
preferential learning from non affiliated individuals in Jackdaws corvus monedula
Behavioural Processes, 2008Co-Authors: Christine Schwab, Thomas Bugnyar, Kurt KotrschalAbstract:It has been suggested that affiliated social relations may facilitate information transfer between individuals. We here tested this rarely examined hypothesis with juvenile and adult Jackdaws (Corvus monedula) in three stimulus enhancement tasks, both in a non-food context (experiment 1) and in a food context (experiments 2 and 3). We first show that siblings and pair partners maintain stronger bonded social relations than do non-siblings and non-pair partners. We therefore tested individuals in sibling and non-sibling dyads and, later in ontogeny, in pair and non-pair dyads. Jackdaws either did not learn from any other conspecific (experiment 1), or they learned from non-affiliated individuals (non-siblings, non-pair partners in experiments 2 and 3). This may be related to two main characteristics of Jackdaws’ affiliated relationships. First, affiliates share food at a high rate and may rely on their knowledgeable partners to secure food rather than learning from them. Second, affiliates spend most time in close spatial proximity to each other which increases the probability that they simultaneously experience occurrences in their environment. Hence, spatially more distant individuals, which are more likely to be non-affiliated, face different foraging situations and may therefore provide more relevant information which may lead to selective social learning.
-
short term observational spatial memory in Jackdaws corvus monedula and ravens corvus corax
Animal Cognition, 2008Co-Authors: Christelle Scheid, Thomas BugnyarAbstract:Observational spatial memory (OSM) refers to the ability of remembering food caches made by other individuals, enabling observers to find and pilfer the others’ caches. Within birds, OSM has only been demonstrated in corvids, with more social species such as Mexican jays (Aphelocoma ultramarine) showing a higher accuracy of finding conspecific’ caches than less social species such as Clark’s nutcrackers (Nucifraga columbiana). However, socially dynamic corvids such as ravens (Corvus corax) are capable of sophisticated pilfering manoeuvres based on OSM. We here compared the performance of ravens and Jackdaws (Corvus monedula) in a short-term OSM task. In contrast to ravens, Jackdaws are socially cohesive but hardly cache and compete over food caches. Birds had to recover food pieces after watching a human experimenter hiding them in 2, 4 or 6 out of 10 possible locations. Results showed that for tests with two, four and six caches, ravens performed more accurately than expected by chance whereas Jackdaws did not. Moreover, ravens made fewer re-visits to already inspected cache sites than Jackdaws. These findings suggest that the development of observational spatial memory skills is linked with the species’ reliance on food caches rather than with a social life style per se.
-
when what and whom to watch quantifying attention in ravens corvus corax and Jackdaws corvus monedula
Journal of Comparative Psychology, 2007Co-Authors: Christelle Scheid, Friederike Range, Thomas BugnyarAbstract:Complex social life requires monitoring of conspecifics. The amount and focus of attention toward others has been suggested to depend on the social relationships between individuals. Yet there are surprisingly few experiments that have tested these assumptions. This study compared attention patterns toward conspecifics in two corvid species, ravens (Corvus corax) and Jackdaws (Corvus monedula). Birds were confronted with affiliated and non-affiliated conspecifics engaged in foraging and object manipulation. Visual access to the model bird was provided through two observation holes, which allowed measurement of exactly how often and for how long observers watched the other. Overall, ravens were more attentive to conspecifics than were Jackdaws. Moreover, only ravens showed higher interest toward food-related than object-related behaviors of the model and toward close affiliates than non-affiliates by increasing the duration rather than the frequency of looks. These results are in accordance with predictions derived from the species’ foraging biology and suggest that the facultative social, but highly manipulative, ravens use and value information from others differently than do the obligate social Jackdaws.
Gabrielle L Davidson - One of the best experts on this subject based on the ideXlab platform.
-
wild Jackdaws corvus monedula recognize individual humans and may respond to gaze direction with defensive behaviour
Animal Behaviour, 2015Co-Authors: Gabrielle L Davidson, Nicola S. Clayton, Alex ThorntonAbstract:Predator recognition is a prerequisite for antipredator behaviour. Although species level predator recognition is well documented, there is emerging evidence that some birds, including corvids, can differentiate between individual humans that pose different levels of threat. Other predator cues such as gaze direction may offer additional important information regarding the likelihood of an attack, but it is unknown whether wild animals can integrate information about the individual identity and gaze direction of a predator when perceiving threat levels. Here we measured wild Jackdaws' responses to human head orientation, directed towards or away from their nestbox containing chicks. To test whether aversive responses to gaze direction were integrated with information about human identity, the human presenting gaze cues wore one of two masks: a ‘threatening’ mask that had previously been worn when handling the Jackdaws' chicks and a ‘neutral mask’ that had previously been worn when walking by, but not disturbing the nest. Latency to return to the nestbox was significantly higher when the threatening mask rather than the neutral mask was worn, but it was not influenced by head direction. However, once a Jackdaw landed outside the nestbox, there was a nonsignificant trend for it to be quicker to enter the box when the human was gazing towards, rather than away from the box. These results indicate that wild Jackdaws can recognize different individual humans and thus differentiate between those wearing a threatening and a neutral mask, and respond defensively by guarding their chicks from potential threat. Jackdaws may integrate both predator identity and gaze cues; however, predation risk is primarily perceived through individual human recognition.
-
salient eyes deter conspecific nest intruders in wild Jackdaws corvus monedula
Biology Letters, 2014Co-Authors: Gabrielle L Davidson, Nicola S. Clayton, Alex ThorntonAbstract:Animals often respond fearfully when encountering eyes or eye-like shapes. Although gaze aversion has been documented in mammals when avoiding group-member conflict, the importance of eye coloration during interactions between conspecifics has yet to be examined in non-primate species. Jackdaws (Corvus monedula) have near-white irides, which are conspicuous against their dark feathers and visible when seen from outside the cavities where they nest. Because Jackdaws compete for nest sites, their conspicuous eyes may act as a warning signal to indicate that a nest is occupied and deter intrusions by conspecifics. We tested whether Jackdaws’ pale irides serve as a deterrent to prospecting conspecifics by comparing prospectors’ behaviour towards nest-boxes displaying images with bright eyes (BEs) only, a Jackdaw face with natural BEs, or a Jackdaw face with dark eyes. The Jackdaw face with BEs was most effective in deterring birds from making contact with nest-boxes, whereas both BE conditions reduced the amount of time Jackdaws spent in proximity to the image. We suggest BEs in Jackdaws may function to prevent conspecific competitors from approaching occupied nest sites.
Dennis Hasselquist - One of the best experts on this subject based on the ideXlab platform.
-
yolk androgens and the development of avian immunity an experiment in Jackdaws corvus monedula
The Journal of Experimental Biology, 2009Co-Authors: Maria I Sandell, Michael Tobler, Dennis HasselquistAbstract:Maternally derived androgens have been shown to influence offspring phenotype in various ways. In birds, the benefits of prenatal androgen exposure, such as increased competitiveness and accelerated growth in nestlings, have been suggested to be balanced by costs, such as reduced immune function. In this study, we used an integrative approach to examine the influence of yolk androgens on the development of immune function in Jackdaw (Corvus monedula) nestlings. Specifically, we tested whether the effects of yolk androgens on offspring immunity may extend over the first few days of life and be detectable even after several weeks. We manipulated yolk androgen concentrations in Jackdaw eggs and estimated immune responsiveness by challenging the young with different pathogens at different stages of the nestling period. Six-day-old chicks hatched from eggs with elevated yolk androgen levels had lower pre-challenge antibody titres against lipopolysaccharide (LPS) than control chicks. However, antibody titres against LPS did not differ between treatment groups eight days after a challenge with LPS. During the late nestling phase, both humoral (towards diphtheria/tetanus antigens) and cell-mediated (towards phytohaemagglutinin) immune responsiveness were lower in chicks from yolk androgen-treated eggs compared with control chicks. Our experimental study on Jackdaw chicks shows that elevated yolk androgen levels result in a general immunosuppression in offspring; this conclusion was based on results for several immunological tests of both humoral and cell-mediated immunity conducted at 1-2 and 3-4 weeks of age. (Less)
-
yolk androgens and the development of avian immunity an experiment in Jackdaws corvus monedula
The Journal of Experimental Biology, 2009Co-Authors: Maria I Sandell, Michael Tobler, Dennis HasselquistAbstract:Maternally derived androgens have been shown to influence offspring phenotype in various ways. In birds, the benefits of prenatal androgen exposure, such as increased competitiveness and accelerated growth in nestlings, have been suggested to be balanced by costs, such as reduced immune function. In this study, we used an integrative approach to examine the influence of yolk androgens on the development of immune function in Jackdaw (Corvus monedula) nestlings. Specifically, we tested whether the effects of yolk androgens on offspring immunity may extend over the first few days of life and be detectable even after several weeks. We manipulated yolk androgen concentrations in Jackdaw eggs and estimated immune responsiveness by challenging the young with different pathogens at different stages of the nestling period. Six-day-old chicks hatched from eggs with elevated yolk androgen levels had lower pre-challenge antibody titres against lipopolysaccharide (LPS) than control chicks. However, antibody titres against LPS did not differ between treatment groups eight days after a challenge with LPS. During the late nestling phase, both humoral (towards diphtheria/tetanus antigens) and cell-mediated (towards phytohaemagglutinin) immune responsiveness were lower in chicks from yolk androgen-treated eggs compared with control chicks. Our experimental study on Jackdaw chicks shows that elevated yolk androgen levels result in a general immunosuppression in offspring; this conclusion was based on results for several immunological tests of both humoral and cell-mediated immunity conducted at 1-2 and 3-4 weeks of age.
