Corvid Lab

Corvids are large-brained birds, commonly referred to as 'primates of the sky' or 'feathered apes'. We want to understand what their large brains are good for and how they work. Hence, we study corvids under field conditions as well as under controlled conditions in the lab, asking questions like

i) how do birds solve problems posed in daily life,

ii) which cognitive skills underlie that problem solving,

iii) how are these skills acquired and transmitted,

iv) how do these skills differ between closely related species and

v) how do the abilities of corvids compare to those of other large-brained animals like parrots, primates and carnivors.

Our main model system is the common raven Corvus corax, which is the largest member of the corvid family showing a worldwide distribution in the Northern hemisphere. Since 2010, we also work on its smaller sister species in Europe, the carrion crow and hooded crow Corvus corone corone and Corvus corone cornix (two subspecies with a hybridization zone exactly around Vienna). Like ravens, crows are feeding generalists and territorial breeders. In contrast to ravens, they seem to be less specialized on scavenging but to more readily engage in cooperative breeding. We study wild ravens and crows in comparable environments (ravens in the Cumberland Wildpark Grünau and crows in the Tiergarten Schönbrunn, where they snatch food from the zoo animals); in each population, we can recognize around 300 birds individually with the help of rings and wing tags. In addition, we keep captive colonies of ravens and crows at our two outdoor stations (Konrad Lorenz Forschungsstelle, Forschungsstation Haidlhof). Most of the captive birds are very tame, they all know their name and are highly motivated to work in our behavioural experiments.

We use a mix of biological and psychological approaches and techniques, depending on the research questions and ecological relevance. For our current projects on cooperation, for instance, we apply matched-controlled observations, choice experiments and non-invasive hormone sampling via feces and saliva. For our research line on social knowledge and 'politics', we combine radio- and GPS tracking, social network and kinship analyses with acoustical playback experiments and operant learning paradigms on touch screen computers. And for the research on information transmission, we use social learning and group diffusion paradigms, personality tests, video demonstrations and operant problem solving tasks.

Our latest addition to the lab is a captive group of azure-winged magpies Cyanopica cyanus, which has been established in 2014 for studying prosocial behaviour in a cooperatively breeding corvid.

Ongoing and finished projects:


Effect of early-life experience on raven social competence, FWF (P33960): 2020-2024, PI Bugnyar, Co-PI Boucherie

Complexity in social life has been suggested as one of the main driving forces for the evolution of higher cognitive abilities in humans and non-human animals. Recent research corroborates that within a species, individuals differ substantially in their ability to adjust and optimize the expression of social behaviour, resulting in fitness consequences. Early-life social experience has been identified as a key factor for this variation in individual social competence. However, aside of mother-offspring interactions, the role of social partners at this time is little understood. Furthermore, the long-term effects of early-life experience on individual social competences have been hardly investigated under dynamic (field-like) conditions, where individuals can choose whom to join and whom to avoid.

Ravens Corvus corax are large-brained birds that show sophisticated (‘primate-like’) socio-cognitive skills. Raven non-breeders form groups that are structured by different types of social relationships, creating a system of dependent ranks and alliances. Yet, individuals differ substantially in how many conspecifics they interact with and how well they form and maintain relationships.

The aim of this project is to investigate how early-life social experience shapes the development of ravens’ social competence and mediates the expression of their social behaviour in later stages of life. Specifically, we will test the hypothesis that the number of siblings and the patterns of social interactions among siblings and parents will affect individuals’ opportunities to develop their social competences, resulting in i) different social profiles (diversity of social repertoire, quantity and quality of social relationships), ii) differences in social performance (responsiveness to social cues) and iii) differences in social integration and competitiveness in non-breeder groups. The proposed research will take advantage of our established captive colony and unique setting of studying free-ranging ravens. We will experimentally manipulate the brood size of our captive breeding pairs in two subsequent years, varying the number of chicks raised by parents per year; depending on the manipulation, the offspring will have the opportunity to grow up with few or many siblings. Per year, we will follow the young ravens’ development i) during the entire family period, ii) during the formation of the first non-breeder group with same-aged peers in captivity, and iii) during the integration in wild non-breeder groups after transition into free-flight. This integrative approach promises important new perspectives for studying the causes and consequences of inter-individual variation in social behaviour and cognition.

What do crows in the Zoo? FWF, Top Citizen Science project (TCS67); 2019-2021, PI Thomas Bugnyar, Co-PIs Palmyre Boucherie, Didone Frigerio, Regina Kramer

Corvids are renowned for making use of anthropogenic resources. Species like ravens and crows can often be found in and around human settlements, typically in groups of different sizes. Recent research indicates that these groups are not entirely anonymous crowds, as some individuals meet regularly at the same or at different locations. What causes birds to join, and stay, in a particular group is the topic of a current FWF-funded research program, whereby ravens are studied across the Northern Alps, and crows are studied within the city of VIenna.

The objective of the present study is to include visitors of Zoo Vienna (Tiergarten Schönbrunn) in our scientific research on corvids via a citizen science approach. Specifically, citizen scientists shall investigate which species of wild crows regularly use the zoo, where the crows prefer to hang out in the zoo, and what the crows do at the different locations. The goal is to describe the grouping dynamics of crows in the different areas of Zoo Vienna and to test effects of environmental factors like food abundance and predation risk on the birds’ grouping behaviour. Interested visitors will be guided to actively engage in the monitoring of crows via a special app (crowdsourcing); they can also contribute to the improvement of the app and the refinement of research methods (participatory science) in the course of feedback rounds and special workshops.

Fission-fusion dynamics and social cognition in wild ravens, FWF (P29705-B29): 2016-2020, PI Thomas Bugnyar

Complexity in social life has been suggested as one of the main driving forces for the development of higher cognitive abilities in humans and non-human animals. A key aspect of complexity is the formation of social relationships, which become difficult to keep track of when groups increase in size or when individuals vary in spatial cohesion and group membership over time, i.e. they show a high degree of fission-fusion dynamics. Until recently, little attention has been paid to such dynamics, even though highly stable groups are the exception rather than the rule in many social systems outside primates. Hence, the interplay between fission-fusion dynamics, social relationships and cognition is still little understood. Ravens Corvus corax combine features of both, high social complexity and high fission-fusion dynamics. Raven non-breeders form groups that are structured by different types of social relationships, creating a system of dependent ranks and alliances. Yet, these groups are also characterized by high inter-individual variation in fission-fusion dynamics, with some birds staying at a foraging site over long time periods and others for a few days only.

The aim of this project is to investigate i) what causes the pronounced individual differences in fission-fusion dynamics of raven non-breeders and ii) how do these differences in dynamics affect the birds’ knowledge about relationships. Specifically, we will test the hypotheses that i) the birds’ competence of gaining central positions in local social networks affects their decision of whether or not to stay at a given location and that ii) those ravens that tend to stay develop personalized knowledge about their fellow local group members, whereas those ravens that tend to wander around may use rules of thumb in social interactions with local birds. The proposed research will be conducted on our unique study population of wild ravens in the Austrian Alps, out of which >300 individuals are marked; it will combine state-of-art methods of tracking birds and analysing their social networks with experimental manipulation of the temporal group composition and individual tests concerning stress coping and social knowledge. The integrative aspect of the proposed project promises important new perspectives for understanding the development of social profiles and decision-making under conditions of social stability and instability and our understanding of socio-cognitive evolution in general.

The evolution of pro-social concern FWF (P26806): 2014-2017, PI Jorg Massen

In an attempt to better understand evolution of altruism, there has been a recent surge in studies on prosocial behaviours like helping. Next to humans a variety of animals has been tested in experiments on prosociality, with however, rather inconsistent results within and between species and across context. This raises questions about the evolutionary pressures (e.g. aspects of social life) and motivations behind prosocial behaviour (e.g. need, sympathy). Therefore, the aim of the current proposal is twofold: The first aim is to test two main hypotheses about the evolution of prosocial behaviour, namely the cooperative breeding hypothesis and the social bonding hypothesis, by making use of the comparative approach, including species with two distinct social features (cooperative breeding (CB) and social bonds (SB)). To control for effects of common ancestry, next to humans I will include two species per two phylogenetical different lineages (primates: common marmosets (CB) vs. long tailed macaques (SB); and corvids: Iberian magpies (CB) vs. common ravens (SB)). The second aim of the proposal is to test underlying motivation of prosocial behaviour, by confronting all five species with a series of experiments that vary across necessity and costs of prosocial behaviour.

The Evolutionary Roots of Social Comparison DSF, Research Unit (FOR 2150): 2015-2017, PI Julia Fischer, Co-PIs Bugnyar and Thomas Mussweiler

Social comparison processes are a fundamental characteristic of human behavior, and the underlying psychological mechanisms and processes have been intensively investigated in the last decades. Yet, until now, relatively little is known about the evolutionary foundations of social comparisons. Do non-human animals also engage in self-other comparisons or are these extensive social comparisons restricted to humans? Studies on non-human primates indicate that animals may be sensitive to the actions of others and adjust their responses. Chimpanzees and capuchin monkeys, for example, refuse to participate in experiments, if a partner animal is receiving better rewards for the same task. Crows and ravens also show this 'inequity aversion'. These studies suggest that there may be an evolutionary basis for social comparisons, but until now the underlying mechanisms have never been explored systematically. In an attempt to fill this important gap in understanding, the present project aims to elucidate the evolutionary roots of social comparisons. We will adopt a comparative approach and combine experimental paradigms from social psychology with animal behavior research methods. Specifically, in an analogy to classic research on social comparison processes in humans, we will examine how the performance of a partner influences subjects' performance behavior in monkeys (long-tailed macaques, Macaca fascicularis) and birds (carrion crows, Corvus corone). These species are particularly skilled at social tasks and thus ideally suited for our comparative research endeavor. More specifically, to examine whether specific features of social comparisons are already evident in non-human animals, we will use classic paradigms that have been developed to examine the underlying mechanisms of social comparisons in humans. Using parallel performances on touch-screen setups, we will investigate whether social comparisons in monkeys and birds are influenced by the relative difference between the subject's and the co-actor's performance as well as the personal relationship between them (Line 1), the social status of the subject within its group (Line 2) as well as prior priming procedures to shift the focus to similarity or dissimilarity features, respectively (Line 3). To validate the comparative approach we will conduct the experiments of Line 1 and 3 with human participants, too. Furthermore, experiments of Line 2 are in close collaboration to P7 reflecting our ambition to strive for a truly interdisciplinary approach.

COBRA (Cognition and Brains) EU, FP7-People (Marie Curie Actions IRSES): 2013-2015, PI Bugnyar

The joint exchange program involved the movement of three experienced researchers between the Universities of Vienna, Austria, University of St Andrews, UK, Ruhr University in Bochum, Germany, and University of Newcastle, Australia. Specifically, a researcher from Newcastle spent 6 months in Europe, split between St Andrews, Vienna, and Bochum. Researchers from Bochum and Vienna visited Newcastle for 6 months. At both their home institution and during each secondment, exchange researchers have collected data towards a geographically global research project that aims to use a collection of avian species as model systems to understand: 1. The role of behavioural flexibility in species' adaptation to urbanization, and 2. The extent to which behavioural flexibility is associated with changes in brain anatomy. The program was structured along four work packages (WP1-4). While WP1 concerned the project management and coordination, WP2-4 concerned the empirical studies on Indian mynahs (WP2), European crows (WP3) and European songbirds like house sparrows and great tits (WP4). Birds were tested in the field with simple problem solving tasks for their behavioural flexibility along a rural to urban gradient. For instance, they had to remove a cork that was blocking the access to food at a known feeder. By examining several species, in several geographical locations, using several different measures of behavioural flexibility, and describing associated brain changes, we find support for the hypothesis that increasing behavioural flexibility in increasingly urbanized environments is a general effect. Specifically, urban birds tend to be more exploratory and more risk taking than rural birds, but they do not show any differences in innovativeness, sociality, or responses to predators. These findings clearly demonstrate what factors makes urban birds 'special' and provide hints for when to expect species differences. The results likely have implications for conservation attempts of declining species and the management of invasive species. They also highlight the importance of comparative studies at different places that could only be achieved by close collaboration between different researchers and their working groups.

Modeling Social Transmission in Corvids WWTF (CS 11-008): 2012-1015, PI Christine Schwab, Co-PI Bugnyar

Humans are experts when it comes to learning from others. We learn by observing and imitating a wide range of other persons, starting with family members and expanding to teachers, friends, peers, or even unfamiliar persons. Further, an important learning strategy in humans is to conform with others, i.e. performing the same behaviour as the majority and/or trustable persons. In this project we investigate if crows, Corvus corone, and ravens, Corvus corax, apply similar social learning strategies. These two species are exceptionally suitable because, similar to humans, they exhibit a social system comprising on one side long-term partnerships and on the other side (sub-) group formation with high degrees of fission-fusion dynamics. Also, they maintain qualitatively different relationships with conspecifics. We will investigate how these various social networks influence the patterns of how social information spreads through populations of wild and captive birds. The results from our project will help us understanding the general principles underlying (human) culture.

Raven Politics: Understanding and Use of Social Relationships FWF, START (Y366-B17): 2008-1014, PI Bugnyar

Social life has been suggested as one of the main driving forces for the development of higher cognitive abilities in non-human, and human, primates. Yet there are open questions concerning the mechanisms underlying 'intelligent' behaviour and the socio-ecological conditions that promote investment in cognitive skills. Recently, the idea of the bird family Corvidae representing a mirror group to the primates in respect to cognitive capacities has gained momentum. Understanding the social life of corvids may thus be critical in our attempt to understand primate cognition, since comparison between these groups may offer the unique opportunity to identify which cognitive abilities are common to social living irrespective of phylogeny and how selection has acted to produce these solutions. The intend in this proposal is therefore to investigate social complexity as driving force for brain evolution in corvids and to provide a comprehensive study on the use of social knowledge in an avian model system, the common raven Corvus corax. Ravens show striking abilities in judging and manipulating competitors but also engage in referential communication, social learning, and various forms of cooperation on the basis of social relationships. This makes them promising candidates to examine their 'political' skills from a Machiavellian and a Vygotskian point of view. Hence, this proposal aims at testing what ravens know about other individuals and their social relations and how they make use of their knowledge in daily life. Studies shall follow two parallel lines of research, building blocks (i) on individual recognition and understanding of dyadic and triadic relations and (ii) on the formation, regulation, and use of valuable relations under fission-fusion dynamics. Furthermore, studies shall feature a combination of laboratory and field work by utilizing our unique captive colony of hand-raised adult birds, their yearly offspring that will be observed first in captivity and then in the field, and habituated wild birds. Finally, studies shall be conducted in collaboration with leading experts in primatology, experimental psychology and behavioural biology, enabling me to utilize a variety of methods (e.g. operant procedures, playbacks, matched-controlled observations, hormonal correlates) on one model system and to selectively conduct comparative studies with closely related species to address effects of phylogeny and ecology. The integrative aspect of the proposed project shall open new possibilities in the research on avian cognition and is expected to have both an impact on current hypotheses on mental evolution and a strong outreach component to lay persons. If birds with a radically different neurobiology and evolutionary trajectory to that of primates come to understand, and use, their social world in a similar way to primates, this would provide strong support for the idea of a convergent evolution and help us understand the selection pressures that may have boosted the evolution of sophisticated mental skills in non-human, and human, primates.

Cooperation, Collaborators, and Cognition FWF, Lise Meitner program for scientists from abroad (M1351-B17): 2012-1013, PI Jorg Massen, Co-PI and host Bugnyar

Cooperation is a useful strategy to gain benefits that cannot be obtained alone, yet is characterized by risky investments. To deal with these uncertainties several mechanisms may have evolved. It has been argued that among group members or known individuals cooperation is unconsciously mediated by emotions. Yet, when dealing with unfamiliar individuals or strangers, human cooperation is governed by complex cognitive decisions involving the calculation of costs/benefits and the understanding of roles and intentions of collaborating individuals. Whether non-human animals also employ different decision rules for cooperation with either known or unknown individuals remains unknown. This study tests experimentally which behavioural decision rules ravens use in their cooperative behaviour with conspecifics of different familiarity. Ravens interact regularly with both familiar and unfamiliar conspecifics and are renowned for advanced socio-cognitive skills. The experiments aim to conceive whether ravens have a preference for cooperation with familiar individuals, whether they prefer an equal distribution of rewards for their cooperative act and whether ravens can calculate costs and benefits of their cooperation and act accordingly. Moreover, the experiments are complimented with an observational study on wild ravens, investigating the contingency of exchange patterns for different commodities in either familiar or unfamiliar dyads.

COCOR (Cooperation in Corvids): Affiliate Relations and Cooperation in Ravens, Corvus corax ESF-EUROCORES framework TECT (I105-G11): 2007-2010, PI Bugnyar

Observational evidence suggests that corvid flocks represent individualized societies with members selectively exchanging low- and high-risks behaviours such as preening and coalition formation. Moreover, recent studies emphasize a crucial role of affiliate relationships that may form between siblings but also between non-related individuals. What is not yet clear is to what extent individuals make tactical use of their relations in cooperative interactions. The aim of the project is to 1) test if ravens' affiliate relationships work as alliances in conflicts, leading to a system of dependent ranks both within and between sexes, 2) determine if, and how, individuals maintain affiliate relations when their partners are experimentally prevented from retaliating social support and 3) examine the birds' willingness to share resources with 'reliable' and 'unreliable' partners.

Cooperation and economic behaviour in corvids EU, FP6-NEST (INCORE): 2007-2010, PI Bugnyar

Corvids have been suggested to show complex cognitive abilities similar to those of primates in the context of similar socio-ecological problems. One of the most fascinating aspects of their social life is the tactical and economical use of cooperative behaviour. Corvids are known to facultatively engage in helping at the nest (e.g. carrion crows), active recruitment of non-relatives to food sources (e.g. ravens), food sharing (e.g. jackdaws), coalitionary support between and within sexes (e.g. ravens, rooks), and post-conflict consolation (e.g. ravens, rooks). Taken together, results indicate a high flexibility in the birds' decision of whether or not to cooperate in certain situations, some knowledge about potential cooperation partners and the use of tools both in the social and technical domain. So far, issues related to corvid-cooperation have been investigated as isolated topics, focusing either on specific proximate or functional aspects. Extending the view of different programs, coordinating ongoing studies and adjusting already-used procedures pose technical and practical challenges and call for improved networking between the established labs in Austria (KL Research Station, Univ. Vienna), France (Univ. Strasbourg), Great Britain (Univ. Cambridge, Univ. Oxford), Spain (Univ. Valladolid) and Italy (Univ. Trieste). This work package is aimed to improve the exchange of information between the European corvid labs in order to coordinate their activities and integrate their ongoing work on cooperative behaviour into the broad framework of other European programs (GEBACO, TECT).


Peer-reviewed papers associated with this project:


Gallego-Abenza, M., Blum, C. & Bugnyar, T. (2021). Who is crying wolf? Seasonal effect on anti-predator response to age-specific alarm-calls in common ravens, Corvus corax. Learning & Behavior,


Beck, K.B., Loretto, M.-C. & Bugnyar, T. 2020. Effects of site fidelity, group size and age on food-caching behaviour of common ravens, Corvus corax. Animal Behaviour, 164, 51-64.

Davídková, M., Veselý, P., Syrová, M., Nácarová, J. & Bugnyar, T. 2020. Ravens respond to unfamiliar corvid alarm calls. Journal of Ornithology, 161 (4), 967-975. 10.1007/s10336-020-01781-w

Gallego-Abenza, M., Loretto, M.-C. & Bugnyar, T. 2020. Decision time modulates social foraging success in wild common ravens, Corvus corax. Ethology, 126 (4), 413-422.

Loretto, M.-C., Schuster, R., Federspiel, I.G., Heinrich, B. & Bugnyar, T. 2020. Contextual imitation in juvenile common ravens (Corvus corax). Animal Behaviour, 163, 127-134.

Sierro, J., Loretto, M.-C., Szipl, G., Massen, J.J.M., & Bugnyar, T. (2020). Food calling in ravens (Corvus corax) revisited: who is addressed? Ethology, 126 (2), 257-266.


Boucherie, P.H., Loretto, M.-C., Massen, J.J.M. & Bugnyar, T. 2019. What constitutes ‘social complexity’ and ‘social intelligence’ in birds? Lessons from ravens. Behavioral Ecology and Sociobiology, 73 (1), 12. 10.1007/s00265-018-2607-2

*Uhl, F., Ringler, M., Miller, R., Deventer, S.A., Bugnyar, T. & Schwab, C. 2019. Counting crows: population structure and group size variation in an urban population of crows. Behavioral Ecology, 30 (1), 57-67. 10.1093/beheco/ary157


*Marchand, P., Loretto, M.-C., Henry, P.-Y., Duriez, O., Jiguet, F., Bugnyar, T. & Itty, C. 2018. Relocations and one-time disturbance fail to sustainably disperse non-breeding common ravens Corvus corax due to homing behaviour and extensive home ranges. European Journal of Wildlife Research, 64 (5), 57. 10.1007/s10344-018-1217-7


*Loretto, M.-C., Schuster, R., Itty, C., Marchand, P., Genero, F. & Bugnyar, T. 2017. Fission-fusion dynamics over large distances in raven non-breeders. Scientific Reports, 7, 380.

Szipl, G., Ringler, E., Spreafico, M. & Bugnyar, T. 2017. Calls during agonistic interactions vary with arousal and raise audience attention in ravens. Frontiers in Zoology, 14, 57.

* funded mainly by my previous project Y366-B17