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Author Bílá, K.; Beránková, J.; Veselý, P.; Bugnyar, T.; Schwab, C. url  doi
openurl 
  Title Responses of urban crows to con- and hetero-specific alarm calls in predator and non-predator zoo enclosures Type Journal Article
  Year 2017 Publication Animal Cognition Abbreviated Journal Anim. Cogn.  
  Volume 20 Issue 1 Pages 43-51  
  Keywords  
  Abstract Urban animals and birds in particular are able to cope with diverse novel threats in a city environment such as avoiding novel, unfamiliar predators. Predator avoidance often includes alarm signals that can be used also by hetero-specifics, which is mainly the case in mixed-species flocks. It can also occur when species do not form flocks but co-occur together. In this study we tested whether urban crows use alarm calls of conspecifics and hetero-specifics (jackdaws, Corvus monedula) differently in a predator and a non-predator context with partly novel and unfamiliar zoo animal species. Birds were tested at the Tiergarten Schönbrunn in the city of Vienna by playing back con- and hetero-specific alarm calls and control stimuli (great tit song and no stimuli) at predator (wolf, polar bear) and non-predator (eland antelope and cranes, peccaries) enclosures. We recorded responses of crows as the percentage of birds flying away after hearing the playback (out of those present before the playback) and as the number of vocalizations given by the present birds. A significantly higher percentage of crows flew away after hearing either con- or hetero-specific alarm calls, but it did not significantly differ between the predator and the non-predator context. Crows treated jackdaw calls just as crow calls, indicating that they make proper use of hetero-specific alarm calls. Responding similarly in both contexts may suggest that the crows were uncertain about the threat a particular zoo animal represents and were generally cautious. In the predator context, however, a high percentage of crows also flew away upon hearing the great tit control song which suggests that they may still evaluate those species which occasionally killed crows as more dangerous and respond to any conspicuous sound.  
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  ISSN 1435-9456 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Equine Behaviour @ team @ Bílá2017 Serial 6159  
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Author Griffin, A.S.; Tebbich, S.; Bugnyar, T. url  doi
openurl 
  Title Animal cognition in a human-dominated world Type Journal Article
  Year 2017 Publication Animal Cognition Abbreviated Journal Anim. Cogn.  
  Volume 20 Issue 1 Pages 1-6  
  Keywords  
  Abstract In the USA, each year, up to one billion birds are estimated to die from colliding with windowpanes (Sabo et al. 2016). A further 573,000 are struck down by wind turbines, along with 888,000 bats (Smallwood 2013). Worldwide, unintended capture in fishing devices is recognized as the single most serious global threat to migratory, long-lived marine taxa including turtles, birds, mammals and sharks (Wallace et al. 2013). Estimates put the number of amphibians killed per year on Australian roads at 5 million (Seiler 2003). The likelihood of a green turtle erroneously ingesting plastic debris, often by mistaking them for food, rose from 30% in 1985 to almost 50% in 2012 (Schuyler et al. 2013). Human-induced rapid environmental change (HIREC, sensu Sih et al. 2011) is filling animals’ environments with new threats which bear little or excessive similarity to those they have encountered in their evolutionary history (Dwernychuk and Boag 1972; Patten and Kelley 2010; Witherington 1997). As a consequence, many of the stimuli involved fall outside the adaptive processing space of animals’ evolutionary perceptual, learning, memory and decision-making systems, making individuals particularly vulnerable to their impact.  
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  ISSN 1435-9456 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Equine Behaviour @ team @ Griffin2017 Serial 6129  
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Author Schmidt, J.; Scheid, C.; Kotrschal, K.; Bugnyar, T.; Schloegl, C. url  doi
openurl 
  Title Gaze direction – A cue for hidden food in rooks (Corvus frugilegus)? Type Journal Article
  Year 2011 Publication Behavioural Processes Abbreviated Journal  
  Volume 88 Issue 2 Pages 88-93  
  Keywords Gaze; Object choice; Corvids; Effort; Rooks  
  Abstract Other individual's head- and eye-directions can be used as social cues indicating the presence of important events. Among birds, ravens and rooks have been shown to co-orient with conspecifics and with humans by following their gaze direction into distant space and behind visual screens. Both species use screens to cache food in private; also, it had been suggested that they may rely on gaze cues to detect hidden food. However, in an object-choice task, ravens failed to do so, and their competitive lifestyle may have prevented them from relying on these cues. Here we tested closely related and cooperative rooks. Food was hidden in one of two cups and the experimenter gazed at the baited cup. In a second experiment, we aimed to increase the birds’ motivation to choose correctly by increasing the investment needed to obtain the reward. To do so, the birds had to pull on a string to obtain the cup. Here, the birds as a group tended to rely on gaze cues. In addition, individual birds quickly learned to use the cue in both experiments. Although rooks may not use gaze cues to find hidden food spontaneously, they may quickly learn to do so.  
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  Series Volume Series Issue Edition  
  ISSN 0376-6357 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Equine Behaviour @ team @ Serial 5420  
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Author Schwab, C.; Bugnyar, T.; Schloegl, C.; Kotrschal, K. url  doi
openurl 
  Title Enhanced social learning between siblings in common ravens, Corvus corax Type Journal Article
  Year 2008 Publication Animal Behaviour. Abbreviated Journal Anim. Behav.  
  Volume 75 Issue 2 Pages 501-508  
  Keywords affiliation; cognition; common raven; Corvus corax; siblings; social learning; social relations  
  Abstract It has been suggested that social dynamics affect social learning but empirical support for this idea is scarce. Here we show that affiliate relationships among kin indeed enhance the performance of common ravens, Corvus corax, in a social learning task. Via daily behavioural protocols we first monitored social dynamics in our group of captive young ravens. Siblings spent significantly more time in close proximity to each other than did nonsiblings. We subsequently tested birds on a stimulus enhancement task in model-observer dyads composed of both siblings and nonsiblings. During demonstration the observer could watch the model manipulating one particular object (target object) in an adjacent room. After removing the model, the observer was confronted with five different objects including the former target object. Observers from sibling dyads handled the target object for significantly longer periods of time as compared with the other four available objects, whereas observers from nonsibling dyads did not show a preference for the target object. Also, siblings matched the model's decision to cache or not to cache objects significantly more often than did nonsiblings. Hence, siblings were likely to attend to both, the behaviour of the model (caching or noncaching) and object-specific details. Our results support the hypothesis that affiliate relations between individuals affect the transmission of information and may lead to directed social learning even when spatial proximity has been experimentally controlled for.  
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  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0003-3472 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Equine Behaviour @ team @ Serial 5300  
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Author Bugnyar, T. url  doi
openurl 
  Title Knower–guesser differentiation in ravens: others' viewpoints matter Type Journal Article
  Year 2011 Publication Proceedings of the Royal Society B: Biological Sciences Abbreviated Journal Proc. Roy. Soc. Lond. B Biol. Sci.  
  Volume 278 Issue 1705 Pages 634-640  
  Keywords  
  Abstract Differentiating between individuals with different knowledge states is an important step in child development and has been considered as a hallmark in human evolution. Recently, primates and corvids have been reported to pass knower–guesser tasks, raising the possibility of mental attribution skills in non-human animals. Yet, it has been difficult to distinguish ‘mind-reading’ from behaviour-reading alternatives, specifically the use of behavioural cues and/or the application of associatively learned rules. Here, I show that ravens (Corvus corax) observing an experimenter hiding food are capable of predicting the behaviour of bystanders that had been visible at both, none or just one of two caching events. Manipulating the competitors' visual field independently of the view of the test-subject resulted in an instant drop in performance, whereas controls for behavioural cues had no such effect. These findings indicate that ravens not only remember whom they have seen at caching but also take into account that the other's view was blocked. Notably, it does not suffice for the birds to associate specific competitors with specific caches. These results support the idea that certain socio-ecological conditions may select for similar cognitive abilities in distantly related species and that some birds have evolved analogous precursors to a human theory-of-mind.  
  Address raven; Corvus corax; knowledge attribution; perspective; competitive food retrieval; caching  
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  Notes Approved no  
  Call Number Equine Behaviour @ team @ Serial 5287  
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Author Fraser, O.N.; Bugnyar, T. url  doi
openurl 
  Title Do Ravens Show Consolation? Responses to Distressed Others Type Journal Article
  Year 2010 Publication PLoS ONE Abbreviated Journal PLoS ONE  
  Volume 5 Issue 5 Pages e10605  
  Keywords  
  Abstract <sec> <title>Background</title> <p>Bystander affiliation (post-conflict affiliation from an uninvolved bystander to the conflict victim) may represent an expression of empathy in which the bystander consoles the victim to alleviate the victim's distress (“consolation”). However, alternative hypotheses for the function of bystander affiliation also exist. Determining whether ravens spontaneously offer consolation to distressed partners may not only help us to understand how animals deal with the costs of aggressive conflict, but may also play an important role in the empathy debate.</p> </sec><sec> <title>Methodology/Principal findings</title> <p>This study investigates the post-conflict behavior of ravens, applying the predictive framework for the function of bystander affiliation for the first time in a non-ape species. We found weak evidence for reconciliation (post-conflict affiliation between former opponents), but strong evidence for both bystander affiliation and solicited bystander affiliation (post-conflict affiliation from the victim to a bystander). Bystanders involved in both interactions were likely to share a valuable relationship with the victim. Bystander affiliation offered to the victim was more likely to occur after intense conflicts. Renewed aggression was less likely to occur after the victim solicited affiliation from a bystander.</p> </sec><sec> <title>Conclusions/Significance</title> <p>Our findings suggest that in ravens, bystanders may console victims with whom they share a valuable relationship, thus alleviating the victims' post-conflict distress. Conversely victims may affiliate with bystanders after a conflict in order to reduce the likelihood of renewed aggression. These results stress the importance of relationship quality in determining the occurrence and function of post-conflict interactions, and show that ravens may be sensitive to the emotions of others.</p> </sec>  
  Address  
  Corporate Author Thesis  
  Publisher Public Library of Science Place of Publication Editor  
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  Notes Approved no  
  Call Number Equine Behaviour @ team @ Serial 5195  
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Author Bugnyar, T.; Stöwe, M.; Heinrich, B. doi  openurl
  Title Ravens, Corvus corax, follow gaze direction of humans around obstacles Type Journal Article
  Year 2004 Publication Proceedings of the Royal Society B: Biological Sciences Abbreviated Journal Proc. Roy. Soc. Lond. B Biol. Sci.  
  Volume 271 Issue 1546 Pages 1331-1336  
  Keywords  
  Abstract The ability to follow gaze (i.e. head and eye direction) has recently been shown for social mammals, particularly primates. In most studies, individuals could use gaze direction as a behavioural cue without understanding that the view of others may be different from their own. Here, we show that hand–raised ravens not only visually co–orient with the look–ups of a human experimenter but also reposition themselves to follow the experimenter's gaze around a visual barrier. Birds were capable of visual co–orientation already as fledglings but consistently tracked gaze direction behind obstacles not before six months of age. These results raise the possibility that sub–adult and adult ravens can project a line of sight for the other person into the distance. To what extent ravens may attribute mental significance to the visual behaviour of others is discussed.  
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  Notes 10.1098/rspb.2004.2738 Approved no  
  Call Number Equine Behaviour @ team @ Serial 5009  
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Author Range, F.; Horn, L.; Bugnyar, T.; Gajdon, G.; Huber, L. doi  openurl
  Title Social attention in keas, dogs, and human children Type Journal Article
  Year 2009 Publication Animal Cognition Abbreviated Journal Anim. Cogn.  
  Volume 12 Issue 1 Pages 181-192  
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  Abstract Abstract: Understanding animals" abilities to cooperate with and learn from each other has been an active field of research in recent years. One important basis for all types of social interactions is the disposition of animals to pay attention to each other-a factor often neglected in discussions and experiments. Since attention differs between species as well as between individuals, it is likely to influence the amount and type of information different species and/or observers may extract from conspecifics in any given situation. Here, we carried out a standardized comparative study on attention towards a model demonstrating food-related behavior in keas, dogs and children. In a series of experimental sessions, individuals watched different conspecific models while searching, manipulating and feeding. Visual access to the demonstration was provided by two observation holes, which allowed us to determine exactly how often and for how long observers watched the model. We found profound differences in the factors that influence attention within as well as between the tested species. This study suggests that attention should be incorporated as an important variable when testing species in social situations.  
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  Notes Approved no  
  Call Number Equine Behaviour @ team @ Serial 4713  
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Author Schloegl, C.; Kotrschal, K.; Bugnyar, T. url  doi
openurl 
  Title Modifying the object-choice task: Is the way you look important for ravens? Type Journal Article
  Year 2008 Publication Behavioural Processes Abbreviated Journal Behav. Process.  
  Volume 77 Issue 1 Pages 61-65  
  Keywords Gaze; Modification; Object-choice task; Raven  
  Abstract Most animals seem to have difficulties in using gaze cues to find hidden food in object-choice tasks. For instance, chimpanzees usually fail in these tests, even though they are capable of following other's gaze geometrically behind barriers. Similar to chimpanzees, common ravens are skilled in tracking other's gaze but fail in object-choice tasks. We here explored whether procedural modifications, which had been used successfully in chimpanzees, would also yield positive results in ravens. In our modifications (a) the experimenter approached the cup while gazing at it, (b) the gaze cue was accompanied by a sound and (c) the experimenter could actually see the food while giving the gaze cue. Two out of seven birds performed above chance level in some of these conditions. However, we ascribe this improvement to the individuals' learning ability rather than to an understanding of the communicative nature of the task. This interpretation is further supported by results of a follow-up experiment suggesting that ravens may not rely on conspecifics' gaze cues for finding food caches in a natural foraging context. In sum, our results suggest that ravens may not transfer their gaze follow abilities to foraging situations involving hidden food.  
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  Notes Approved no  
  Call Number Equine Behaviour @ team @ Serial 4505  
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Author Schloegl, C.; Kotrschal, K.; Bugnyar, T. url  doi
openurl 
  Title Gaze following in common ravens, Corvus corax: ontogeny and habituation Type Journal Article
  Year 2007 Publication Animal Behaviour. Abbreviated Journal Anim. Behav.  
  Volume 74 Issue 4 Pages 769-778  
  Keywords Corvus corax; gaze following; habituation; ontogenetic development; raven  
  Abstract Co-orientation with others by using their gaze direction is considered to be adaptive for detecting food or predators or monitoring social interactions. Like the great apes, common ravens are capable of following human experimenters' gaze direction not only into distant space but also behind visual barriers. We investigated the ontogenetic development of these abilities by confronting birds with a human foster parent looking up (experiment 1) and behind visual barriers (experiment 3) and their modification by habituation (experiments 2 and 4). We tested a group of 12 hand-reared ravens during their first 10 months of life. Ravens responded to others' look-ups soon after fledging but could track their gaze behind a visual barrier only 4 months later, at the age they usually become independent from their parents. Furthermore, ravens quickly ceased responding to repeated look-ups by the model, but did not habituate to repeated gaze cues directed behind a barrier. Our findings support the idea that the two modes of gaze following reflect different cognitive levels in ravens and, possibly, have different functions.  
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  Notes Approved no  
  Call Number Equine Behaviour @ team @ Serial 4204  
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