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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 Department of Biology, University of Vermont, Burlington, VT 05405, USA. thomas.bugnyar@univie.ac.at  
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  Series Volume Series Issue Edition  
  ISSN 1435-9448 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:16909235 Approved no  
  Call Number Equine Behaviour @ team @ Serial 2449  
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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 University of Vermont, USA  
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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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Author Hunt, G.R.; Rutledge, R.B.; Gray, R.D. doi  openurl
  Title The right tool for the job: what strategies do wild New Caledonian crows use? Type Journal Article
  Year 2006 Publication Animal Cognition Abbreviated Journal Anim. Cogn.  
  Volume 9 Issue 4 Pages 307-316  
  Keywords Analysis of Variance; Animals; Comprehension; *Crows; Female; *Intelligence; Male; *Problem Solving; *Tool Use Behavior  
  Abstract New Caledonian crows Corvus moneduloides (NC crows) display sophisticated tool manufacture in the wild, but the cognitive strategy underlying these skills is poorly understood. Here, we investigate what strategy two free-living NC crows used in response to a tool-length task. The crows manufactured tools to extract food from vertical holes of different depths. The first tools they made in visits were of a similar length regardless of the hole depth. The typical length was usually too short to extract food from the deep holes, which ruled out a strategy of immediate causal inference on the first attempt in a trial. When the first tool failed, the crows made second tools significantly longer than the unsuccessful first tools. There was no evidence that the crows made the lengths of first tools to directly match hole depth. We argue that NC crows may generally use a two-stage heuristic strategy to solve tool problems and that performance on the first attempt in a trial is not necessarily the 'gold standard' for assessing folk physics.  
  Address Department of Psychology, University of Auckland, Private Bag 92019, Auckland, New Zealand. grhunt10@hotmail.com  
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  Language English Summary Language Original Title  
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  Series Volume Series Issue Edition  
  ISSN 1435-9448 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:16941156 Approved no  
  Call Number Equine Behaviour @ team @ Serial 2442  
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Author Lazareva, O.F.; Smirnova, A.A.; Bagozkaja, M.S.; Zorina, Z.A.; Rayevsky, V.V.; Wasserman, E.A. doi  openurl
  Title Transitive responding in hooded crows requires linearly ordered stimuli Type Journal Article
  Year 2004 Publication Journal of the experimental analysis of behavior Abbreviated Journal J Exp Anal Behav  
  Volume 82 Issue 1 Pages 1-19  
  Keywords Animals; *Association; Cognition/physiology; Crows; Discrimination (Psychology); *Discrimination Learning; Feedback; Reinforcement (Psychology); Visual Perception/physiology  
  Abstract Eight crows were taught to discriminate overlapping pairs of visual stimuli (A+ B-, B+ C-, C+ D-, and D+ E-). For 4 birds, the stimuli were colored cards with a circle of the same color on the reverse side whose diameter decreased from A to E (ordered feedback group). These circles were made available for comparison to potentially help the crows order the stimuli along a physical dimension. For the other 4 birds, the circles corresponding to the colored cards had the same diameter (constant feedback group). In later testing, a novel choice pair (BD) was presented. Reinforcement history involving stimuli B and D was controlled so that the reinforcement/nonreinforcement ratios for the latter would be greater than for the former. If, during the BD test, the crows chose between stimuli according to these reinforcement/nonreinforcement ratios, then they should prefer D; if they chose according to the diameter of the feedback stimuli, then they should prefer B. In the ordered feedback group, the crows strongly preferred B over D; in the constant feedback group, the crows' choice did not differ significantly from chance. These results, plus simulations using associative models, suggest that the orderability of the postchoice feedback stimuli is important for crows' transitive responding.  
  Address Institute of Higher Nervous Activity, Moscow State University. olga-lazareva@uiowa.edu  
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  Series Volume Series Issue Edition  
  ISSN 0022-5002 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:15484868 Approved no  
  Call Number refbase @ user @ Serial 612  
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Author McCoy, D.E.; Schiestl, M.; Neilands, P.; Hassall, R.; Gray, R.D.; Taylor, A.H. url  doi
openurl 
  Title New Caledonian Crows Behave Optimistically after Using Tools Type Journal Article
  Year 2019 Publication Current Biology Abbreviated Journal  
  Volume Issue Pages  
  Keywords tool use; New Caledonian crows; optimism; cognitive bias; animal emotion; intrinsic motivation; comparative cognition  
  Abstract Summary Are complex, species-specific behaviors in animals reinforced by material reward alone or do they also induce positive emotions? Many adaptive human behaviors are intrinsically motivated: they not only improve our material outcomes, but improve our affect as well [1, 2, 3, 4, 5, 6, 7, 8]. Work to date on animal optimism, as an indicator of positive affect, has generally focused on how animals react to change in their circumstances, such as when their environment is enriched [9, 10, 11, 12, 13, 14] or they are manipulated by humans [15, 16, 17, 18, 19, 20, 21, 22, 23], rather than whether complex actions improve emotional state. Here, we show that wild New Caledonian crows are optimistic after tool use, a complex, species-specific behavior. We further demonstrate that this finding cannot be explained by the crows needing to put more effort into gaining food. Our findings therefore raise the possibility that intrinsic motivation (enjoyment) may be a fundamental proximate cause in the evolution of tool use and other complex behaviors. Video Abstract  
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  Series Volume Series Issue Edition  
  ISSN 0960-9822 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Equine Behaviour @ team @ Serial 6581  
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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 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 Straub, A. doi  openurl
  Title An intelligent crow beats a lab Type Journal Article
  Year 2007 Publication Science (New York, N.Y.) Abbreviated Journal Science  
  Volume 316 Issue 5825 Pages 688  
  Keywords Animals; *Behavior, Animal; *Cognition; *Crows; Dogs; Intelligence; Memory  
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  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1095-9203 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:17478698 Approved no  
  Call Number Equine Behaviour @ team @ Serial 4102  
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Author Tebbich, S.; Seed, A.M.; Emery, N.J.; Clayton, N.S. doi  openurl
  Title Non-tool-using rooks, Corvus frugilegus, solve the trap-tube problem Type Journal Article
  Year 2007 Publication Animal Cognition Abbreviated Journal Anim. Cogn.  
  Volume 10 Issue 2 Pages 225-231  
  Keywords Animals; Behavior, Animal/*physiology; Cognition/*physiology; Crows/*physiology; Female; Male; Problem Solving/*physiology  
  Abstract The trap-tube problem is used to assess whether an individual is able to foresee the outcome of its actions. To solve the task, an animal must use a tool to push a piece of food out of a tube, which has a trap along its length. An animal may learn to avoid the trap through a rule based on associative processes, e.g. using the distance of trap or food as a cue, or by understanding relations between cause and effect. This task has been used to test physical cognition in a number of tool-using species, but never a non-tool-user. We developed an experimental design that enabled us to test non-tool-using rooks, Corvus frugilegus. Our modification of the task removed the cognitive requirements of active tool use but still allowed us to test whether rooks can solve the trap-tube problem, and if so how. Additionally, we developed two new control tasks to determine whether rooks were able to transfer knowledge to similar, but novel problems, thus revealing more about the mechanisms involved in solving the task. We found that three out of seven rooks solved the modified trap-tube problem task, showing that the ability to solve the trap-tube problem is not restricted to tool-using animals. We found no evidence that the birds solved the task using an understanding of its causal properties, given that none of the birds passed the novel transfer tasks.  
  Address Department of Experimental Psychology, University of Cambridge, Cambridge, CB2 3EB, UK. st281@cam.ac.uk  
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  ISSN 1435-9448 ISBN Medium  
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  Notes PMID:17171360 Approved no  
  Call Number Equine Behaviour @ team @ Serial 2429  
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Author Weir, A.A.S.; Kacelnik, A. doi  openurl
  Title A New Caledonian crow (Corvus moneduloides) creatively re-designs tools by bending or unbending aluminium strips Type Journal Article
  Year 2006 Publication Animal Cognition Abbreviated Journal Anim. Cogn.  
  Volume 9 Issue 4 Pages 317-334  
  Keywords Animals; *Comprehension; *Crows; Female; Learning; *Motor Skills; *Problem Solving; *Tool Use Behavior  
  Abstract Previous observations of a New Caledonian crow (Corvus moneduloides) spontaneously bending wire and using it as a hook [Weir et al. (2002) Science 297:981] have prompted questions about the extent to which these animals 'understand' the physical causality involved in how hooks work and how to make them. To approach this issue we examine how the same subject (“Betty”) performed in three experiments with novel material, which needed to be either bent or unbent in order to function to retrieve food. These tasks exclude the possibility of success by repetition of patterns of movement similar to those employed before. Betty quickly developed novel techniques to bend the material, and appropriately modified it on four of five trials when unbending was required. She did not mechanically apply a previously learned set of movements to the new situations, and instead sought new solutions to each problem. However, the details of her behaviour preclude concluding definitely that she understood and planned her actions: in some cases she probed with the unmodified tools before modifying them, or attempted to use the unmodified (unsuitable) end of the tool after modification. Gauging New Caledonian crows' level of understanding is not yet possible, but the observed behaviour is consistent with a partial understanding of physical tasks at a level that exceeds that previously attained by any other non-human subject, including apes.  
  Address Department of Zoology, South Parks Road, Oxford, OX1 3PS, UK. alex.weir@magdalen.oxon.org  
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  Series Volume Series Issue Edition  
  ISSN 1435-9448 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:17024509 Approved no  
  Call Number Equine Behaviour @ team @ Serial 2436  
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