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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.  
  Address (up)  
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  ISSN 0376-6357 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Equine Behaviour @ team @ Serial 5420  
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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.  
  Address (up)  
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  Series Volume Series Issue Edition  
  ISSN 1435-9456 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Equine Behaviour @ team @ Griffin2017 Serial 6129  
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Author Bugnyar, T.; Heinrich, B. doi  openurl
  Title Pilfering ravens, Corvus corax, adjust their behaviour to social context and identity of competitors Type Journal Article
  Year 2006 Publication Animal Cognition Abbreviated Journal Anim. Cogn.  
  Volume 9 Issue 4 Pages 369-376  
  Keywords Adaptation, Psychological; Animals; *Behavior, Animal; *Competitive Behavior; Crows/*physiology; *Deception; Feeding Behavior; Female; Male; Social Behavior; *Social Environment  
  Abstract Like other corvids, food-storing ravens protect their caches from being pilfered by conspecifics by means of aggression and by re-caching. In the wild and in captivity, potential pilferers rarely approach caches until the storers have left the cache vicinity. When storers are experimentally prevented from leaving, pilferers first search at places other than the cache sites. These behaviours raise the possibility that ravens are capable of withholding intentions and providing false information to avoid provoking the storers' aggression for cache protection. Alternatively, birds may refrain from pilfering to avoid conflicts with dominants. Here we examined whether ravens adjust their pilfer tactics according to social context and type of competitors. We allowed birds that had witnessed a conspecific making caches to pilfer those caches either in private, together with the storer, or together with a conspecific bystander that had not created the caches (non-storer) but had seen them being made. Compared to in-private trials, ravens delayed approaching the caches only in the presence of storers. Furthermore, they quickly engaged in searching away from the caches when together with dominant storers but directly approached the caches when together with dominant non-storers. These findings demonstrate that ravens selectively alter their pilfer behaviour with those individuals that are likely to defend the caches (storers) and support the interpretation that they are deceptively manipulating the others' behaviour.  
  Address (up) Department of Biology, University of Vermont, Burlington, VT 05405, USA. thomas.bugnyar@univie.ac.at  
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  Language English Summary Language Original Title  
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  Series Volume Series Issue Edition  
  ISSN 1435-9448 ISBN Medium  
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  Notes PMID:16909235 Approved no  
  Call Number Equine Behaviour @ team @ Serial 2449  
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Author Range, F.; Bugnyar, T.; Schlogl, C.; Kotrschal, K. doi  openurl
  Title Individual and sex differences in learning abilities of ravens Type Journal Article
  Year 2006 Publication Behavioural Processes Abbreviated Journal Behav. Process.  
  Volume 73 Issue 1 Pages 100-106  
  Keywords Animals; Behavior, Animal/*physiology; *Crows; Discrimination Learning/*physiology; Exploratory Behavior/physiology; Female; *Individuality; Male; Sex Factors; Spatial Behavior  
  Abstract Behavioral and physiological characteristics of individuals within the same species have been found to be stable across time and contexts. In this study, we investigated individual differences in learning abilities and object and social manipulation to test for consistency within individuals across different tasks. Individual ravens (Corvus corax) were tested in simple color and position discrimination tasks to establish their learning abilities. We found that males were significantly better in the acquisition of the first discrimination task and the object manipulation task, but not in any of the other tasks. Furthermore, faster learners engaged less often in manipulations of conspecifics and exploration of objects to get access to food. No relationship between object and social manipulation and reversal training were found. Our results suggest that individual differences in regard to the acquisition of new tasks may be related to personalities or at least object manipulation in ravens.  
  Address (up) Konrad Lorenz Research Station, A-4645 Gruenau 11, Austria. friederike.range@univie.ac.at  
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  Series Volume Series Issue Edition  
  ISSN 0376-6357 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:16675158 Approved no  
  Call Number Equine Behaviour @ team @ Serial 4146  
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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 (up) 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 Heinrich, B.; Bugnyar, T. openurl 
  Title Just how smart are ravens? Type Journal Article
  Year 2007 Publication Scientific American Abbreviated Journal Sci Am  
  Volume 296 Issue 4 Pages 64-71  
  Keywords Animals; *Behavior, Animal; Crows/*physiology; Environment; *Intelligence; Predatory Behavior; Problem Solving; Thinking  
  Abstract  
  Address (up) University of Vermont, USA  
  Corporate Author Thesis  
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  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0036-8733 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:17479632 Approved no  
  Call Number Equine Behaviour @ team @ Serial 4101  
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