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Thomas Bugnyar - One of the best experts on this subject based on the ideXlab platform.
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pair bond characteristics and maintenance in free flying jackdaws Corvus Monedula effects of social context and season
Journal of Avian Biology, 2015Co-Authors: Robin J Kubitza, Thomas Bugnyar, Christine SchwabAbstract:Most birds rely on cooperation between pair partners for breeding. In long-term monogamous species, pair bonds are considered the basic units of social organization, albeit these birds often form foraging, roosting or breeding groups in which they repeatedly interact with numerous conspecifics. Focusing on jackdaws Corvus Monedula, we here investigated 1) the interplay between pair bond and group dynamics in several social contexts and 2) how pair partners differ in individual effort of pair bond maintenance. Based on long-term data on free-flying birds, we quantified social interactions between group members within three positive contexts (spatial proximity, feeding and sociopositive interactions) for different periods of the year (non-breeding, pre-breeding, parental care). On the group level, we found that the number of interaction partners was highest in the spatial proximity context while in the feeding and sociopositive contexts the number of interaction partners was low and moderately low, respectively. Interactions were reciprocated within almost all contexts and periods. Investigating subgrouping within the flock, results showed that interactions were preferentially directed towards the respective pair partner compared to unmated adults. When determining pair partner effort, both sexes similarly invested most into mutual proximity during late winter, thereby refreshing their bond before the onset of breeding. Paired males fed their mates over the entire year at similar rates while paired females hardly fed their mates at all but engaged in sociopositive behaviors instead. We conclude that jackdaws actively seek out positive social ties to flock members (close proximity, sociopositive behavior), at certain times of the year. Thus, the group functions as a dynamic social unit, nested within are highly cooperative pair bonds. Both sexes invested into the bond with different social behaviors and different levels of effort, yet these are likely male and female proximate mechanisms aimed at maintaining and perpetuating the pair bond.
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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).
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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.
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recipients affect prosocial and altruistic choices in jackdaws Corvus Monedula
PLOS ONE, 2012Co-Authors: Christine Schwab, Kurt Kotrschal, Ruth Swoboda, Thomas BugnyarAbstract:Other-regarding preferences are a critical feature of human cooperation but to what extent non-human animals exhibit these preferences is a matter of intense discussion. We tested whether jackdaws show prosocial behaviour (providing benefits to others at no cost to themselves) and altruism (providing benefits to others while incurring costs) with both sibling and non-sibling recipients. In the prosocial condition, a box was baited on both the actor's and the recipient's side (1/1 option), whereas another box provided food only for the actor (1/0 option). In the altruistic condition, the boxes contained food for either the actor (1/0 option) or the recipient (0/1 option). The proportion of selfish (1/0 option) and cooperative (1/1 and 0/1 option, respectively) actors' choices was significantly affected by the recipients' behaviour. If recipients approached the boxes first and positioned themselves next to the box baited on their side, trying to access the food reward (recipient-first trials), actors were significantly more cooperative than when the actors approached the boxes first and made their choice prior to the recipients' arrival (actor-first trials). Further, in recipient-first trials actors were more cooperative towards recipients of the opposite sex, an effect that was even more pronounced in the altruistic condition. Hence, at no cost to the actors, all recipients could significantly influence the actors' behaviour, whereas at high costs this could be achieved even more so by recipients of different sex. Local/stimulus enhancement is discussed as the most likely cognitive mechanism to account for these effects.
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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.
Alex Thornton - One of the best experts on this subject based on the ideXlab platform.
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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.
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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, Nicola S Clayton, Karen A. Spencer, 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.
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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.
Terry Burke - One of the best experts on this subject based on the ideXlab platform.
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strict monogamy in a semi colonial passerine the jackdaw Corvus Monedula
Journal of Avian Biology, 2000Co-Authors: I G Henderson, P J B Hart, Terry BurkeAbstract:In this study we used DNA fingerprinting to provide an accurate measure of paternity in a nest-box colony of Jackdaws. The species is a semi-colonial, socially monogamous passerine which establishes long-term pair bonds. Parents raise a single annual brood in which 50% brood reduction is commonplace. However, nest sites are a limited resource, non-breeding adults are also common around colonies and males are frequently separated from their incubating females during the fertile egg-laying period so that opportunities arise for extra-pair copulation. The parentage analysis, however, revealed no cases of extra-pair fertilisation (EPF) or intra-specific brood parasitism. Therefore fledgling output or survival is likely to be a good measure of individual reproductive success in this species. The lack of EPFs is not explained by nesting synchrony and we discuss the relative costs and benefits to females of seeking EPFs; the likelihood that paternal care and a life-history strategy similar to many long-lived non-passerines may also constrain the species to monogamy.
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Strict monogamy in a semi‐colonial passerine: the Jackdaw Corvus Monedula
Journal of Avian Biology, 2000Co-Authors: I G Henderson, P J B Hart, Terry BurkeAbstract:In this study we used DNA fingerprinting to provide an accurate measure of paternity in a nest-box colony of Jackdaws. The species is a semi-colonial, socially monogamous passerine which establishes long-term pair bonds. Parents raise a single annual brood in which 50% brood reduction is commonplace. However, nest sites are a limited resource, non-breeding adults are also common around colonies and males are frequently separated from their incubating females during the fertile egg-laying period so that opportunities arise for extra-pair copulation. The parentage analysis, however, revealed no cases of extra-pair fertilisation (EPF) or intra-specific brood parasitism. Therefore fledgling output or survival is likely to be a good measure of individual reproductive success in this species. The lack of EPFs is not explained by nesting synchrony and we discuss the relative costs and benefits to females of seeking EPFs; the likelihood that paternal care and a life-history strategy similar to many long-lived non-passerines may also constrain the species to monogamy.
Juan Jose Soler - One of the best experts on this subject based on the ideXlab platform.
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does the risk of nest predation affect clutch size in the jackdaw Corvus Monedula
Bird Study, 2009Co-Authors: Manuel Soler, Juan Jose SolerAbstract:The nest predation hypothesis predicts that clutch size should be inversely related to the risk of nest predation. In this paper we analyse data on nest predation, clutch size and fledgling production in 128 Jackdaw nests in order to test if clutches are larger in the safer sites. The predation rate was positively correlated with the minimum nest-entrance dimensions (predation is greater in nests with large entrances). Clutch size was not related to the risk of nest predation, and our data do not therefore support the nest predation hypothesis.
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effects of experimental food provisioning on reproduction in the jackdaw Corvus Monedula a semi colonial species
Ibis, 2008Co-Authors: Manuel Soler, Juan Jose SolerAbstract:Two Jackdaw Corvus Monedula colonies were given supplementary food before and during breeding in 1983. Breeding density and cavity use were compared with those of the same colonies in previous years, when no food was provided. Predation rate and reproductive parameters were compared with those in the same colonies in previous years and with those of two control colonies, without experimental food. Jackdaws preferred safe cavities with small minimum nest-entrance dimensions and avoided those with a high risk of nest predation. In experimental (fed) colonies, however, there was a tendency to use all cavities, which resulted in an increased breeding density. No nests were preyed upon by Ravens Corvus corax in the experimental colonies because supplemental food favoured group defence by increasing colony size and by increasing the time the Jackdaws spent in the colony. Additional food advanced laying date, increased clutch size independently of laying date and increased fledging success. Supplementary food significantly increased fledging success in less than half of all experimental studies on birds. We suggest that the key to this problem is the species' breeding strategy, and we show that supplementary food significantly increased fledging success in brood-reduction strategist species but not in species which directly adjusted their clutch size.
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Effects of experimental food provisioning on reproduction in the Jackdaw Corvus Monedula, a semi‐colonial species
Ibis, 2008Co-Authors: Manuel Soler, Juan Jose SolerAbstract:Two Jackdaw Corvus Monedula colonies were given supplementary food before and during breeding in 1983. Breeding density and cavity use were compared with those of the same colonies in previous years, when no food was provided. Predation rate and reproductive parameters were compared with those in the same colonies in previous years and with those of two control colonies, without experimental food. Jackdaws preferred safe cavities with small minimum nest-entrance dimensions and avoided those with a high risk of nest predation. In experimental (fed) colonies, however, there was a tendency to use all cavities, which resulted in an increased breeding density. No nests were preyed upon by Ravens Corvus corax in the experimental colonies because supplemental food favoured group defence by increasing colony size and by increasing the time the Jackdaws spent in the colony. Additional food advanced laying date, increased clutch size independently of laying date and increased fledging success. Supplementary food significantly increased fledging success in less than half of all experimental studies on birds. We suggest that the key to this problem is the species' breeding strategy, and we show that supplementary food significantly increased fledging success in brood-reduction strategist species but not in species which directly adjusted their clutch size.
Mečislovas Žalakevičius - One of the best experts on this subject based on the ideXlab platform.
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molecular and morphological investigations of sarcocystis Corvusi sp nov from the jackdaw Corvus Monedula
Parasitology Research, 2013Co-Authors: Petras Prakas, Liuda Kutkienė, Dalius Butkauskas, Aniolas Sruoga, Mečislovas ŽalakevičiusAbstract:One type of sarcocyst was found in two of eight investigated jackdaws (Corvus Monedula) and proposed as Sarcocystis Corvusi sp. nov. By light microscope, cysts resembled a thick thread and were very long (the largest fragment found amounted to 6 mm) and relatively thin (up to 60 μm). The cyst wall measured <1 μm and seemed smooth. Using a computerized image analysis system, knolls, which resembled protrusions, were visible on the wall surface. Ultrastructurally, the cyst wall was wavy and reached up to 1.1 μm. The waves were of different heights and resembled low protrusions. The parasitophorous vacuolar membrane had many invaginations. Lancet- or orange segment-shaped cystozoites were 5.9–7.3 μm long. These sarcocysts had type-1 tissue cyst wall. According to 18S rRNA, 28S rRNA genes and ITS-1 region sequences, it was shown that S. Corvusi is a genetically separate species. On the basis of these genetic markers, S. Corvusi was most closely related to S. columbae, S. calchasi and S. wobeseri which parasitize birds and are characterized by the same type of sarcocyst wall.
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Molecular and morphological investigations of Sarcocystis Corvusi sp. nov. from the jackdaw (Corvus Monedula).
Parasitology Research, 2012Co-Authors: Petras Prakas, Liuda Kutkienė, Dalius Butkauskas, Aniolas Sruoga, Mečislovas ŽalakevičiusAbstract:One type of sarcocyst was found in two of eight investigated jackdaws (Corvus Monedula) and proposed as Sarcocystis Corvusi sp. nov. By light microscope, cysts resembled a thick thread and were very long (the largest fragment found amounted to 6 mm) and relatively thin (up to 60 μm). The cyst wall measured
