Abstract: Predation is a major force in shaping biological communities, both over ecological and evolutionary timescales. In response to predation pressure, prey have evolved characteristics designed to mitigate predation pressure. We evaluated predator foraging biases in relation to prey characteristics across 16 vertebrate communities. We show that although predator biases vary, some prey traits are consistently associated with predator diet composition. Within their acceptable prey size range, predators show positive bias toward larger bodied prey, small-brained prey (controlling for body size), small group size, and terrestriality. Thus, whether predator foraging decisions are passive or active, predator choice exerts differential pressure on prey species according to prey characteristics. Predator biases also were positively associated with early age at maturity, supporting the role of mortality in driving life-history characteristics. These results support several theoretical models of predation including its role as a selective force driving evolutionary changes in life history, brain size and sociality, optimal diet theory, and antiapostatic predation.

Abstract: Through combining theoretical models and empirical data, complexity science has increased our understanding of social behavior of animals, in particular of social insects, primates, and fish. What are missing are studies of collective behavior of huge swarms of birds. Recently detailed empirical data have been collected of the swarming maneuvers of large flocks of thousands of starlings (Sturnus vulgaris) at their communal sleeping site (roost). Their flocking maneuvers are of dazzling complexity in their changes in density and flock shape, but the processes underlying them are still a mystery. Recent models show that flocking may arise by self-organization from rules of co-ordination with nearby neighbors, but patterns in these models come nowhere near the complexity of those of the real starlings. The question of this paper, therefore, is whether such complex patterns can emerge by self-organization. In our computer model, called StarDisplay, we combine the usual rules of co-ordination based on separation, attraction, and alignment with specifics of starling behavior: 1) simplified aerodynamics of flight, especially rolling during turning, 2) movement above a “roosting area” (sleeping site), and 3) the low fixed number of interaction neighbors (i.e., the topological range). Our model generates patterns that resemble remarkably not only qualitative but also quantitative empirical data collected in Rome through video recordings and position measurements by stereo photography. Our results provide new insights into the mechanisms underlying complex flocking maneuvers of starlings and other birds.

Abstract: The objective of the study was to determine which cross-country obstacles are more difficult for eventing horses. Jumping scores were considered in terms of the horse's reaction to novelty and to the fearfulness of novel objects which are the fences situated in novel terrain. The data concerned 11 classes of One to Four Star level (stars showing the difficulty of the class) held at the Olympic Games and three international Three Day Events. A total of 400 entries, in which 259 horses jumped 372 obstacles were considered. Scores of 11,341 jumps at particular fences were categorized either as faulty jumps or non-faulty jumps. Factors describing the fences versus the jumping scores were studied with least square analysis of variance, with respect to the interaction between the star level and the fence traits. The overall frequency of faults at the cross-country amounted to 4.33 ± 0.57%. Among the effects analyzed, the difficulty of cross-country fences for the horses depends upon whether an obstacle is single or is an element of a combination, whether it is straight or requiring an effort in both height and spread, is broad or narrow, has a solid top or a brush, has an alternative or not and whether it is a water crossing or not. At One Star level, the less experienced horses react differently to certain fence traits compared to horses participating in Three or Four Star levels. It is concluded that the equine visionary system, being less developed towards identification of stationary objects than the human visionary system may be a key towards explaining the horse's behaviour while jumping the obstacle. The height-spread obstacles, those of the narrow front, with the brush and with the alternative seem to involve more faults because of the equine low-acuity vision. The same reason may justify the similar frequency of faults at the single obstacles and the first elements in combinations. Accurate methods of measuring equine vision would complement behavioural tests and should both be introduced into the selection of eventing horses.

Abstract: Recent studies have suggested that crib-biting in horses is associated with diminished capacity of learning or coping with stress. Such findings raise the question whether trainability, which is fundamentally important in practice, could also be affected by stereotypic behaviour. Trainability of a horse is difficult to assess in simple tests, however, it is reliably estimated by experienced riders. To assess trainability and other characteristics related to that, a questionnaire survey was conducted with the owners of 50 crib-biting and 50 control horses. Where possible, control horses were selected from the same establishment as crib-biters. Groups did not differ significantly regarding age, breed, gender, training level or usage. Principal component analysis revealed three main factors which can be labelled as [`]Anxiety', [`]Affability' and [`]Trainability'. The [`]Anxiety' factor consisted of the items [`]Nervousness', [`]Excitability', [`]Panic', [`]Inconsistent emotionality', [`]Vigilance', [`]Skittishness', and [`]Timidity'. [`]Affability' consisted of [`]Friendliness toward people', [`]Cooperation', [`]Docility' and [`]Friendliness toward horses'. [`]Trainability' involved [`]Concentration', [`]Trainability', [`]Memory', and [`]Perseverance'. Temperament traits were not affected by age, gender, breed or training level, but the usage of the horse and the presence of crib-biting behaviour had significant effects. Competition horses had lower level of [`]Anxiety' (p = 0.032) and higher level of [`]Trainability' (p = 0.068) than leisure horses. Crib-biting horses had significantly lower level of [`]Anxiety' than control horses (p < 0.001), while [`]Trainability' and [`]Affability' did not differ between groups (p = 0.823 and p = 0.543, respectively). Competition horses are more often exposed to novel environment and to frightening stimuli (e.g. colourful obstacles) than leisure horses and therefore might have also become more habituated to these types of stimuli. Coping with novel situation may be enhanced by defusing nervous behaviour by the more experienced riders of competition. Previous studies indicated crib-biting horses to be less reactive when challenged as compared to control horses. We suggest that the virtual calmness and lower nervousness of the crib-biting horses might be due to the passive coping style of these animals. [`]Affability' of horses might be more related to housing and management conditions than to crib-biting. Contrary to expectations, scores on [`]Trainability' had not coincided with the impaired learning of crib-biting horses reported in laboratory tests. However, previous behavioural tests on equine learning rarely had a direct relevance to the training abilities of the horses. Our results do not support crib-biting stereotypy to affect performance in training, which is a complex learning process involving cooperation and docility in the social environment.

Abstract: Repeated encounters with unfamiliar conspecifics in large groups of domestic birds create a potentially stressful social environment which can affect the birds' emotional reactivity and consequently their welfare. As social relationships between young quail are particularly influenced by their social motivation (i.e., the motivation to seek close proximity with conspecifics), it is likely that the reaction of quail to repeated encounters with strangers depends on their social motivation. The aim of this study was to assess the emotional reactivity of quail chicks with high (HSR) or low (LSR) social motivation housed under stable and unstable social conditions. Quail chicks were housed either in stable pairs, i.e. remaining with the same cagemate until testing (NHSR = 19 and NLSR = 18 pairs), or in unstable pairs, i.e. changing cagemate daily from 6 to 13 days of age (NHSR = 20 and NLSR = 19 pairs). Emotional reactivity was measured using a novel object test on day 14, and an emergence test and a tonic immobility test on day 15. The social condition affected the number of induction attempts of quail chicks in the tonic immobility test but only in the LSR ones. This number of inductions was lower under the stable than under the unstable social condition in this line. Moreover, the HSR chicks showed greater disturbance than the LSR ones in the three behavioural tests. In conclusion, social instability did not affect the emotional reactivity of HSR quail chicks, which was high, regardless of social condition. In contrast, repeated cagemate changes seemed to decrease the emotional reactivity of LSR quail chicks. These results suggest that low social motivation makes easier the adaptation to the potential social instability encountered in large flocks.