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Author Range, F.; Bugnyar, T.; Schlogl, C.; Kotrschal, K.
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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Language English Summary Language Original Title
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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.; Heinrich, B.
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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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.
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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ISSN 0036-8733 ISBN Medium
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Notes PMID:17479632 Approved no
Call Number Equine Behaviour @ team @ Serial 4101
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Author Bugnyar, T.; Stöwe, M.; Heinrich, B.
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 Bugnyar, T.; Kotrschal, K.
Title Movement coordination and signalling in ravens (Corvus corax): an experimental field study Type Journal Article
Year 2001 Publication Acta ethologica Abbreviated Journal Acta. Ethol.
Volume 3 Issue 2 Pages 101-109
Keywords Ravens – Corvus corax – Foraging – Coordination – Communication
Abstract Vagrant non-breeding ravens frequently attract conspecifics to rich ephemeral food sources. There, grouping may allow them to overcome the defence of territorial breeders. Here, we focus on ravens making use of regular food supplies in a game park, where they divert food from the provision of park animals. We investigated if ravens foraging in the Cumberland game park (Gr&uuml;nau, Austria) are attentive towards one another when they experience some unpredictability in food provisioning. We confronted a group of 30-50 ravens with two different treatments. Ten minutes ahead of the feeding of either wolves or wild boars we showed buckets containing pieces of meat to the ravens flying overhead. In the reliable cue treatment (RCT), the meat was placed next to one of the two enclosures, whereas in the unreliable cue treatment (UCT), the buckets were placed simultaneously in front of both enclosures though only in one of the enclosures were the animals fed 10 min later. Thus, during RCT but not during UCT, ravens could predict where food would become available. Only during UCT, ravens moved in large groups between the two feeding sites. Many ravens moving at the same time in the same direction may indicate some co-ordination in space and time, which is most likely achieved by social attraction among individuals. Furthermore, the number of ravens approaching and leaving, respectively, a feeding site cross-correlated with a temporary increase in the rate of a food-associated call, the yell. This suggests that in addition to watching each other, calling may have contributed to group formation. Possible benefits of group formation during food inspection are discussed.
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Notes Approved no
Call Number Serial 2081
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Author Range, F.; Horn, L.; Bugnyar, T.; Gajdon, G.; Huber, L.
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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Call Number Equine Behaviour @ team @ Serial 4713
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Author Bugnyar, T.; Kotrschal, K.
Title Leading a conspecific away from food in ravens ( Corvus corax)? Type Journal Article
Year 2004 Publication Animal Cognition Abbreviated Journal Anim. Cogn.
Volume 7 Issue 2 Pages 69-76
Keywords Misleading – Deception – Raven – Social foraging
Abstract Active misleading of conspecifics has been described as a social strategy mainly for primates. Here we report a raven leading a competitor away from food in a social foraging task. Four individuals had to search and compete for hidden food at color-marked clusters of artificial food caches. At the beginning of the experiment, a subordinate male found and exploited the majority of the food. As a result, the dominant male displaced him from the already opened boxes. The subordinate male then developed a pattern, when the loss of reward to the dominant got high, of moving to unrewarded clusters and opening boxes there. This diversion often led the dominant to approach those unrewarded clusters and the subordinate then had a head start for exploiting the rewarded boxes. Subsequently, however, the dominant male learned not to follow the subordinate to unrewarded clusters and eventually started searching for the reward himself. These interactions between the two males illustrate the ravens' potential for deceptively manipulating conspecifics. We discuss under which circumstances ravens might use this capacity.
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Notes Approved no
Call Number Serial 2080
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Author Bílá, K.; Beránková, J.; Veselý, P.; Bugnyar, T.; Schwab, C.
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
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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
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Call Number Equine Behaviour @ team @ Bílá2017 Serial 6159
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Author Griffin, A.S.; Tebbich, S.; Bugnyar, T.
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
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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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Call Number Equine Behaviour @ team @ Griffin2017 Serial 6129
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Author Bugnyar, T.
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
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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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Call Number Equine Behaviour @ team @ Serial 5287
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