Assessing the reliability of an automated method for measuring dominance hierarchy in non-human primates

Among animal societies, dominance is an important social factor that influences inter-individual relationships. However, assessing dominance hierarchy can be a time-consuming activity which is potentially impeded by environmental factors, difficulties in the recognition of animals, or disturbance of animals during data collection. Here we took advantage of novel devices, machines for automated learning and testing (MALT), designed primarily to study non-human primate cognition, to additionally measure the dominance hierarchy of a semi-free-ranging primate group. When working on a MALT, an animal can be replaced by another, which could reflect an asymmetric dominance relationship. To assess the reliability of our method, we analysed a sample of the automated conflicts with video scoring and found that 74% of these replacements included genuine forms of social displacements. In 10% of the cases, we did not identify social interactions and in the remaining 16% we observed affiliative contacts between the monkeys. We analysed months of daily use of MALT by up to 26 semi-free-ranging Tonkean macaques (Macaca tonkeana) and found that dominance relationships inferred from these interactions strongly correlated with the ones derived from observations of spontaneous agonistic interactions collected during the same time period. An optional filtering procedure designed to exclude chance-driven displacements or affiliative contacts suggests that the presence of 26% of these interactions in data sets did not impair the reliability of this new method. We demonstrate that this method can be used to assess the dynamics of both individual social status, and group-wide hierarchical stability longitudinally with minimal research labour. Further, it facilitates a continuous assessment of dominance hierarchies in captive groups, even during unpredictable environmental or challenging social events, which underlines the usefulness of this method for group management purposes. Altogether, this study supports the use of MALT as a reliable tool to automatically and dynamically assess dominance hierarchy within captive groups of non-human primates, including juveniles, under conditions in which such technology can be used

Foraging tactics and social networks in wild jackdaws

Individual variation in asocial and social behavioural traits can affect patterns of social association. Resultant individual-level variation in sociality can be quantified using social network analysis. Social network analysis has recently been applied to the study of the evolution and development of social behaviour. Though captive systems have provided useful contributions to this endeavour, investigating the factors shaping social structure in wild populations affords superior ecological relevance. The characterisation of the social structure of wild animals has been greatly aided by improvements in automated data collection methods, particularly the miniaturisation of Radio-Frequency Identification (RFID) technology for the purposes of studying the social foraging behaviour of wild birds. In this thesis, I use RFID methods to examine the factors influencing between-individual variation in foraging routines (Chapter Two) and social network position (Chapter Three) in wild populations of a colonial corvid species, the jackdaw (Corvus monedula). I then relate social network position to reproductive success (Chapter Three) and investigate the developmental plasticity of jackdaw social behaviour by determining the effect of early life conditions on social network position (Chapter Four). Finally, I describe the fine-scale temporal dynamics of social foraging, the nature of accompaniment during paired foraging and the foraging benefits of social support (Chapter Five)

The causes and consequences of individual differences in cognitive performances in relation to the social environment in pheasants

Identifying the causes and consequences of intra-specific variation in cognitive abilities is fundamental to our understanding of the evolution of cognition. The social environment and cognitive abilities appear inextricably linked, yet evidence for how the social environment affects cognitive performances and further, how cognitive performances influence the social environment, has seldom been explored. Using the pheasant, Phasianus colchicus, I explore the relationships between individual variation in cognitive performances in relation to broad and fine-scale structure of the social environment and endeavour to separate cause and consequence. I demonstrate a positive causal effect of the broad-scale social environment on cognitive performances by observing increases in the accuracy of spatial discrimination performances when individuals are in larger groups (Chapter Two and Chapter Four). I show that the positive effects of larger group size occur over a relatively short period (less than one week), suggesting that cognitive performances are flexible in response to the social environment and I suggest four potential mechanisms. I show that while males are part of a social hierarchy, spatial discrimination performances are related to this fine-scale social structure and higher-ranking males outperform lower ranking males (Chapter Three). When attempting to determine cause and consequence, I found that spatial learning performances early in life did not predict adult cognitive performances on the same task or predict their adult social rank (Chapter Four). Hence, my results do not support that social rank is a consequence of spatial learning abilities in male pheasants. The relationship between spatial learning performances and social rank was found in adult males that had their social rank artificially elevated, suggesting that cognitive performances were not simply the result of the current social environment but remain closely related to past agonistic relationships. I did not find a relationship between early life aggression with performances on either a spatial or a non-spatial task in females or males (Chapter Five). This highlights the importance of investigating early life relationships and suggests that the relationship between spatial learning and aggression in adult males may become associated over time as a consequence of further spatial learning experiences, and, or, aggressive interactions. I then demonstrate a consequence of individual variation in cognitive abilities and show that adult foraging associations in the wild disassort by early life cognitive performances (Chapter Six). Individuals with good inhibitory control performance and poor visual discrimination performances were more central in social networks. I propose that differences in cognitive abilities manifest in foraging strategy and influence the resulting social structure. The implications of this predictable social structure remain to be explored. Finally, I discuss these results and how they contribute to our understanding of how the social environment causes individual differences in cognitive performances, as well as how variation in cognitive performances may shape the social environment. I suggest the potential implications of these findings and ideas for future work.European Research Council (ERC

Avian cognition in a changing world

Humans are altering the natural environment at an unprecedented rate, with profound consequences for non-human animals. However, species differ in how they respond to these ecological changes. Understanding the responses of wildlife to environmental change is vital to conserve biodiversity and mitigate anthropogenic impacts. Behaviour can often act as a rapid adaptation to ecological change, and is influenced by an organism’s ability to acquire and process information from their environment. Despite the importance of cognition in shaping behaviour, little is known about the role of cognition in allowing some species to thrive in human-dominated habitats. In this thesis, I examine how the cognitive abilities of wild jackdaws allow these birds to cope with the challenges of a rapidly changing world. Specifically, I focus on the need to navigate a dynamic social environment, and the need to learn about anthropogenic threats. Firstly, I investigate how jackdaws track their social environment by recognising conspecifics and their relationships. In Chapter 3, I demonstrate that jackdaws individually recognise the contact calls of their breeding partner, but I find no evidence of vocal discrimination beyond the pair bond. In Chapter 4, I use infidelity simulations to investigate whether jackdaws track changes to prevailing social relationships, although I find no evidence that jackdaws respond to relationship information in this experimental context. Secondly, I investigate how jackdaws’ cognitive abilities shape their behaviour during encounters with people, allowing birds to avoid danger whilst exploiting anthropogenic resources. I test the commonly-held preconception that jackdaws identify people carrying shotguns as dangerous (Chapter 5), but find no evidence that jackdaws use objects being carried by people to inform their escape decisions in this case. I also demonstrate that jackdaws learn socially about dangerous people (Chapter 6). Throughout these experiments, jackdaws differed considerably in their behaviour, which may influence individual success in anthropogenic habitats. In Chapter 7, I find that individual jackdaws differ consistently in their responses to human disturbance, but that these differences do not appear to impact reproductive success. Together, my findings highlight the importance of fundamental behavioural and cognitive research in predicting animals’ responses to environmental change.NER

Measuring Behavior 2018 Conference Proceedings

These proceedings contain the papers presented at Measuring Behavior 2018, the 11th International Conference on Methods and Techniques in Behavioral Research. The conference was organised by Manchester Metropolitan University, in collaboration with Noldus Information Technology. The conference was held during June 5th – 8th, 2018 in Manchester, UK. Building on the format that has emerged from previous meetings, we hosted a fascinating program about a wide variety of methodological aspects of the behavioral sciences. We had scientific presentations scheduled into seven general oral sessions and fifteen symposia, which covered a topical spread from rodent to human behavior. We had fourteen demonstrations, in which academics and companies demonstrated their latest prototypes. The scientific program also contained three workshops, one tutorial and a number of scientific discussion sessions. We also had scientific tours of our facilities at Manchester Metropolitan Univeristy, and the nearby British Cycling Velodrome. We hope this proceedings caters for many of your interests and we look forward to seeing and hearing more of your contributions

Change blindness: eradication of gestalt strategies

Arrays of eight, texture-defined rectangles were used as stimuli in a one-shot change blindness (CB) task where there was a 50% chance that one rectangle would change orientation between two successive presentations separated by an interval. CB was eliminated by cueing the target rectangle in the first stimulus, reduced by cueing in the interval and unaffected by cueing in the second presentation. This supports the idea that a representation was formed that persisted through the interval before being 'overwritten' by the second presentation (Landman et al, 2003 Vision Research 43149–164]. Another possibility is that participants used some kind of grouping or Gestalt strategy. To test this we changed the spatial position of the rectangles in the second presentation by shifting them along imaginary spokes (by ±1 degree) emanating from the central fixation point. There was no significant difference seen in performance between this and the standard task [F(1,4)=2.565, p=0.185]. This may suggest two things: (i) Gestalt grouping is not used as a strategy in these tasks, and (ii) it gives further weight to the argument that objects may be stored and retrieved from a pre-attentional store during this task

Body surface temperature as an indicator of physiological state in wild birds

Understanding physiological processes is key to answering the questions of why organisms behave in the way they do, and how they interact with each other, and their environment. Despite technological innovations in recent decades, assessment of physiological state in free-living animals still generally requires subjects to be trapped and handled, so tissues or blood can be sampled, or so measurement devices can be attached or implanted. Such methods limit research to species and individuals that can be caught, potentially restricting the generalisability of findings, and introducing bias. Additionally, natural behaviours are interrupted, and subsequent physiology, behaviour or performance may be altered as a result of the stress of capture, the burden of attached apparatus, or the effects of surgery. Consequently, alternative techniques such as inferring physiological state from traits that do not require invasive sampling would be a valuable development. Body temperature is a particularly promising candidate trait, linked with an array of physiological functions, and having previously been used as a proxy for metabolic activity, stress state and immune challenge. With the advent of low cost, highly portable thermal imaging cameras, physiological ecologists are now presented with unprecedented opportunities to measure body surface temperature non-invasively, and at high frequencies from free-living animals. In this thesis, I investigated relationships between body surface temperatures, measured using thermal imaging from free-living blue tits or captive zebra finches, with physiological measures or situations relevant to the assessment of physiological state. I developed reliable thermal imaging techniques to take non-invasive measurements of body surface temperatures in a variety of contexts, allowing characterisation of physiological responses in real time. My studies of captive birds revealed that activity levels influence body surface temperatures measured from free moving animals, and so should be accounted for in experimental designs. I also successfully acquired body surface temperatures from overwintering blue tits visiting food-baited traps, and from breeding blue tits entering and leaving their nest. Using this data, I showed that body surface temperature exhibits a characteristic response to acute stress, which differs with stressor type. While the mechanisms require explanation, much potentially useful information appears to be stored within body surface temperature dynamics during acute stress. Additionally, I established links between body surface temperature and longer term physiological processes in free-living blue tits. I observed near identical correlations between body surface temperature and body condition across differing seasons and life history stages. Also, I found evidence suggesting both that repeated acute stressors (predation risk and human disturbance) had a chronic effect on body condition breeding blue tits, and that surface temperature in those birds was linked to body condition. If confirmed, these results would be particularly interesting in a conservation physiology context, as it may prove possible to detect a signal of persistent physiological effect(s) relating to human disturbance, non-invasively. Furthermore, my discovery of a further correlation between baseline plasma glucocorticoids and body surface temperature in overwintering birds implies links with the hypothalamic-pituitary-adrenal axis. All of these results combined suggest that body surface temperatures measured using thermal imaging are highly likely to prove useful in determining aspects of physiological state non-invasively from free-living animals. While further investigation and validations are necessary, this work has laid the foundations for an exciting new methodology that could help solve many questions that remain unanswerable using current techniques