Claudia A F Wascher

• Dr. rer. nat.
• Associate Professor at Anglia Ruskin University

Recent years have seen a dramatic rise in the use of passive acoustic monitoring (PAM) for biological and ecological applications, and a corresponding increase in the volume of data generated. However, data sets are often becoming so sizable that analysing them manually is increasingly burdensome and unrealistic. Fortunately, we have also seen a co...

A new study shows that carrion crows use memorized reward associations in a combinatorial way to apply relative probabilistic information to optimize reward outcome. This for the first time shows that a corvid species can flexibly apply statistical inference during decision making.

The phenomenon of human-induced rapid environmental change (HIREC) is a great challenge in the modern world that presents a threat to all species. Research on the effect of anthropogenic noise on free-living wildlife is increasing but the effect of anthropogenic noise on the behaviour and welfare of captive wildlife has received limited attention,...

The fearful ape hypothesis proposes that heightened fearfulness in humans is adaptive. However, despite its attractive anthropocentric narrative, the evidence presented for greater fearfulness in humans versus other apes is not sufficient to support this claim. Conceptualization, context, and comparison are strongly lacking in Grossmann's proposal,...

Anthropogenic noise is a major pollutant in terrestrial and aquatic ecosystems. Since the industrial revolution, human activities have become increasingly noisy, leading to both acute and chronic disturbance of a wide variety of animals. Chronic noise exposure can affect animals over their lifespan, leading to changes in species interactions and li...

A wide range of nonhuman animal species has been shown to be able to respond to human referential signals, such as pointing gestures. The aim of the present study was to replicate previous findings showing cats to be sensitive to human pointing cues (Miklósi et al., 2005). In our study, we presented two types of human pointing gestures-momentary ip...

Anthropogenic disturbances are a major concern for the welfare and conservation of wildlife. We recorded heart rate and body temperature of 20 free-living greylag geese in response to a major regularly re-occurring anthropogenic disturbance-New Year's Eve fireworks. Heart rate and body temperature were significantly higher in the first and second h...

A wide range of non-human animal species have been shown to be able to respond to human referential signals, such as pointing gestures. The aim of the present study was to replicate previous findings showing cats to be sensitive to human pointing cues (Miklósi et al. 2005). In our study, we presented two types of human pointing gestures - momentary...

Behavioral responses of captive animals to the presence of visitors in zoos and wildlife parks can be interpreted as signs of negative (disturbance), neutral or positive (enrichment) welfare. In the present study, we investigated behavioral responses of captive common ravens, Corvus corax and crows, Corvus corone, to the presence of visitors in gen...

Cognitive abilities allow animals to navigate through complex, fluctuating environments. In the present study, we tested the performance of a captive group of eight crows, Corvus corone and 10 domestic chickens, Gallus gallus domesticus , in the cylinder task, as a test of motor inhibitory control and reversal learning as a measure of learning abil...

How individuals interact with their environment and respond to changes is a key area of research in evolutionary biology. A physiological parameter that provides an instant proxy for the activation of the automatic nervous system, and can be measured relatively easily, is modulation of heart rate. Over the past four decades, heart rate has been use...

Environmental enrichment, particularly auditory enrichment, has recently gained attention as a potential method for reducing stress, and encouraging a more diverse behavior repertoire in captive animals. However, the effects of auditory enrichment on behavior are inconclusive between different studies, and interpretation of behavior has proven diff...

In group-living animals, the social environment is thought to affect the probability of parasite transmission. Here, I investigate relationships between social behaviour and gastrointestinal parasite product excretion in the carrion crow (Corvus corone). Individuals from a population of non-cooperatively breeding carrion crows excreted less samples...

Behavioral flexibility should theoretically be positively related to behavioral inhibition (hereafter referred to as inhibition) because one should need to inhibit a previously learned behavior to change their behavior when the task changes (the flexibility component;). However, several investigations show no or mixed support of this hypothesis, wh...

Cognitive abilities allow animals to navigate through complex, fluctuating environments. In the present study, we tested performance of a captive group of eight crows, Corvus corone , and ten domestic chickens, Gallus gallus domesticus , in the cylinder task, as a test of motor inhibitory control, and reversal learning as a measure of learning abil...

In the biological sciences, sexual behaviours in non-human animals are traditionally investigated in the context of reproduction and direct fitness benefits. While the evolutionary functions of non-conceptive sexual behaviours (′socio-sexual′) remain less well explored, these interactions and displays have been suggested to be important for shaping...

The ability to regulate and withhold an immediate behaviour in pursuit of a more advantageous or valuable, albeit delayed, outcome is generally termed 'self-control' and is regarded an important cognitive ability enabling adaptive decision-making in both social and asocial contexts. Abilities to cope with a delay in gratification have been investig...

The social environment strongly affects the physiological stress response in group living animals, which in turn can affect the immune system and increase susceptibility to parasites. Here, I investigate relationships between social behavior and gastrointestinal parasite product excretion in the carrion crow ( Corvus corone ). Individuals from a po...

In their natural environment, animals often make decisions crucial for survival, such as choosing the best patch or food, or the best partner to cooperate. The choice can be compared to a gamble with an outcome that is predictable but not certain, such as rolling a dice. In economics, such a situation is called a risky context. Several models show...

In group-living animals, behavioural interactions with conspecifics strongly modulate an individual's physiological stress response. Stable social relationships may reduce an individual's stress response, which in turn can affect the immune system and health. Ultimately, positive health effects of stable social bonds may contribute to maintaining g...

Human economic transactions are based on complex forms of reciprocity, which involve the capacities to share and to keep track of what was given and received over time. Animals too engage in reciprocal interactions, but mechanisms such as calculated reciprocity have only been shown experimentally in few species. Various forms of cooperation, for ex...

In group living animals, behavioural interactions with conspecifics strongly modulate an individual’s physiological stress response. Stable social relationships may reduce an individual’s stress response, which in turn can affect the immune system and health. Ultimately, positive health effects of stable social bonds may contribute to maintain grou...

Self‐control is critical for both humans and nonhuman animals because it underlies complex cognitive abilities, such as decision‐making and future planning, enabling goal‐directed behavior. For instance, it is positively associated with social competence and life success measures in humans. We present the first review of delay of gratification as a...

In a number of species, consistent behavioral differences between individuals have been described in standardized tests, e.g., novel object, open field test. Different behavioral expressions are reflective of different coping strategies of individuals in stressful situations. A causal link between behavioral responses and the activation of the phys...

Reproductive success in monogamous species is generally affected by both behavioural and hormonal fine-tuning between pair partners. Vigilance, defence and brooding of offspring are among the main parental investments, and often the sexes adopt different roles. In the present study, we investigate how sex differences in parental behaviour and famil...

Animals are expected to be judicious in the use of the energy they gain due to the costs and limits associated with its intake. The management of energy expenditure (EE) exhibited by animals has previously been considered in terms of three patterns: the constrained, independent and performance patterns of energy management. These patterns can be in...

Many studies investigate the decisions made by animals by focusing on their attitudes toward risk, that is, risk-seeking, risk neutrality, or risk aversion. However, little attention has been paid to the extent to which individuals understand the different odds of outcomes. In a previous gambling task involving 18 different lotteries (Pelé, Broihan...

In a number of species, consistent behavioral differences between individuals have been described in standardized tests, e.g. novel object exploration, open field test. Different behavioral expressions are reflective of different coping strategies of individuals in stressful situations. A causal link between behavioral responses and the activation...

The requirements of living in social groups, and forming and maintaining social relationships are hypothesized to be one of the major drivers behind the evolution of cognitive abilities. Most empirical studies investigating the relationships between sociality and cognition compare cognitive performance between species living in systems that differ...

In group living animals, affiliative social interactions maintain cohesion between individuals. Involvement in these interactions is likely to differ between individuals, depending on their sex, age and life history stages. Here we investigated different social network measures to describe greeting interactions within two prides of captive-origin A...

Animals adaptively regulate their metabolic rate and hence energy expenditure over the annual cycle to cope with energetic challenges. We studied energy management in greylag geese. In all geese, profound seasonal changes of heart rate (fH) and body temperature (Tb) showed peaks in summer and troughs during winter, and also daily modulation of fH a...

The reproductive season is energetically costly as revealed by elevated glucocorticoid concentrations, constrained immune functions and an increased risk of infections. Social allies and affiliative interactions may buffer physiological stress responses and thereby alleviate associated effects. In the present study, we investigated the seasonal dif...

In precocial species, large brood sizes are usually considered as beneficial and individuals in larger broods grow faster and are more dominant compared to individuals in small broods. However, little is known whether family size also beneficially affects the offspring's physiology. In the present study, we investigated whether leucocyte profiles i...

The presence of a social partner may significantly contribute to coping with stressful events, whereas dyadic separation generally increases glucocorticoid levels and, thereby, might also affect immune function and health. To study the covariation between social factors, immuno-reactive corticosterone metabolites, haematology and parasite product e...

Background Blood parameters such as haematocrit or leucocyte counts are indicators of immune status and health, which can be affected, in a complex way, by exogenous as well as endogenous factors. Additionally, social context is known to be among the most potent stressors in group living individuals, therefore potentially influencing haematological...

Group living individuals are confronted with a variety of different stressors, with social context being among the most potent ones. Affiliative interactions may buffer individual stress responses and ultimately enhance reproductive success. In the present study, we investigated the relationship between affiliative interactions and excreted cortico...

Individual reproductive success largely depends on the ability to optimize behaviour, immune function and the physiological stress response. We have investigated correlations between behaviour, faecal steroid metabolites, immune parameters, parasite excretion patterns and reproductive output in a critically endangered avian species, the Northern Ba...

Group living individuals are frequently confronted with a variety of different stressors with social context being one of the most potent ones. Even though the activation of the physiological stress response is adaptive in nature, it may have pathological consequences, for instance by negatively affecting the immune system, which is linked to paras...

Affiliative interactions may buffer an individual’s stress response and ultimately enhance reproductive success. The aim of this study was to determine behavioural interactions of breeding partners in the Northern Bald Ibis (Geronticus eremita), a critically endangered bird with a seasonal monogamous mating system. The free flying colony of the Kon...

Partner choice on the basis of an individual's reliability is expected to stabilize social interactions. In this experiment, we tested whether carrion crows (Corvus corone corone) learn to differentiate between calls of reliable or unreliable individuals. Crows were kept in an aviary that comprised four visually but not acoustically isolated compar...

Upon discovering food, common ravens, Corvus corax, produce far-reaching ‘haa’ calls or yells, which are individually distinct and signal food availability to conspecifics. Here, we investigated whether ravens respond differently to ‘haa’ calls of known and unknown individuals. In a paired playback design, we tested responses to ‘haa’ call sequence...

The social intelligence hypothesis links the evolution of exceptional cognitive skills to the requirements of complex social systems. Empirical evidence of a connection between cognitive skills and social behaviour on an individual level is lacking. I investigated how cognitive performance in carrion crows correlates with social behaviour. Social b...

Ambient temperature and air pressure are relevant stimuli that can elicit hormonal responses in alignment with adjusting individuals’ physiology and behaviour. This study investigated possible changes in corticosterone (C) and testosterone (T) and contingencies with behaviour in response to ambient temperature and air pressure, and it evaluated the...

Self-control, that is, overcoming impulsivity towards immediate gratification in favour of a greater but delayed reward, is seen as a valuable skill when making future-oriented decisions. Experimental studies in nonhuman primates revealed that individuals of some species are willing to tolerate delays of up to several minutes in order to gain food...

When humans and animals interact with one another over an extended time span they familiarise and may develop a relationship, which can exert an influence on both partners. For example, the behaviour of an animal in experiments may be affected by its relationship to the human experimenter. However, few studies have systematically examined the impac...

A benefit of group living is the opportunity for individuals to gain valuable information from others, for example about predators, food sources or mate quality. However paying attention to conspecifics also induces costs such as time constraints. In order to optimize information-gaining processes individuals are expected to be selective with regar...

The use and manufacture of tools have been considered to be cognitively demanding and thus a possible driving factor in the evolution of intelligence. In this study, we tested the hypothesis that enhanced physical cognitive abilities evolved in conjunction with the use of tools, by comparing the performance of naturally tool-using and non-tool-usin...

For decades, the benefits and costs of group living were a central topic in the field of behavioural biology (Rubenstein 1978; Krause & Ruxton 2002). Besides the wide-ranging benefits such as predator avoidance (Hamilton 1971; Treherne & Foster 1980; Fels et al. 1995), increased foraging efficiency (Clark & Mangel 1986; Creel 2001), and a wider cho...

Sensitivity to inequity is considered to be a crucial cognitive tool in the evolution of human cooperation. The ability has recently been shown also in primates and dogs, raising the question of an evolutionary basis of inequity aversion. We present first evidence that two bird species are sensitive to other individuals' efforts and payoffs. In a t...

In group living vertebrates, patterns of parasite infection vary within and between populations because of environmental and social factors. In the present study, we investigated patterns of parasite product excretion in graylag geese, focusing on environmental (season and temperature), individual (sex and age), and social factors (pair-bond status...

In group-living animals, it is adaptive to recognize conspecifics on the basis of familiarity or group membership as it allows association with preferred social partners and avoidance of competitors. However, animals do not only associate with conspecifics but also with heterospecifics, for example in mixed-species flocks. Consequently, between-spe...

The ability to control an immediate impulse in return for a more desirable – though delayed – outcome has long been thought to be a uniquely human feature. However, studies on non-human primates revealed that some species are capable of enduring delays in order to get food of higher quality or quantity. Recently two corvid species, common raven (Co...

In group-living vertebrates, reliable social allies play a decisive role in dealing with stressors. For example, support by social allies is known to dampen glucocorticoid responses. It remains unknown, however, how social embedding affects the sympatho-adrenergic axis as indicated by heart rate (HR) in non-human animals. We studied the relationshi...

Evidence for time-dependent calculations about future rewards is scarce in non-human animals. In non-human primates, only great apes are comparable with humans. Still, some species wait for several minutes to obtain a better reward in delayed exchange tasks. Corvids have been shown to match with non-human primates in some time-related tasks. Here,...

Adequate short-term responses to stressors are of great importance for the health and well-being of individuals and factors modulating the physiological stress response (e.g., controllability, suddenness, familiarity) of a stimulus are well described under laboratory conditions. In the present study we aimed at investigating the stress response in...

Social stressors are known to be among the most potent stressors in group-living animals. This is not only manifested in individual physiology (heart rate, glucocorticoids), but also in how individuals behave directly after a conflict. Certain 'stress-related behaviors' such as autopreening, body shaking, scratching and vigilance have been suggeste...

Stress responses involve autonomic, endocrine and behavioural changes. Each of these responses has been studied thoroughly in avian species, but hardly in an integrative way, in free-living birds. This is necessary to reveal the temporal dynamics of the stress response. Towards that goal, we recorded heart rate (HR) and behaviour in free-ranging ma...

As in most social groups, agonistic interactions of various intensities are common in a goose flock. This may cause social stress, modulating heart rate (HR), which may serve as a measure of energetic investment and also of individual emotional involvement. We investigated HR responses to social encounters in 24 free-living greylag geese in an inta...

Lately, Emery et al. developed a bird-specific modification of the "social brain hypothesis", termed "relationship intelligence hypothesis". Although the idea may be valuable, we doubt that it is supported by sufficient evidence and critically discuss some of the arguments raised by the authors in favour of their new idea.

Simply observing other individuals interacting has been shown to affect subsequent behaviour and also hormones in 'bystander' individuals. However, immediate physiological responses of an observer have been hardly investigated. Here we present results on individuals' heart rate (HR) responses during various situations, which occur regularly in a fl...

Physical activity is generally considered as most relevant for modulating heart rate (HR). The authors show here that HR is not only modulated by physical activity but even more by social contexts. HR modulation in three free-ranging, socially embedded, male greylag geese fitted with implanted radiotransmitters was investigated. Measured HR ranged...