Abstract: An animal's level of vigilance depends on various environmental factors such as predator presence or the proximity of conspecific competitors. In addition, several individual traits may influence vigilance. We investigated the effects of body condition, social rank and the state of pregnancy on individual vigilance (scanning) rates in individually marked European rabbits (Oryctolagus cuniculus) of a field enclosure population. We found lower rates in young rabbits than in adult females, but male and female juveniles did not differ. Vigilance of juveniles was positively correlated with their age-dependent body mass (used as a measure of body condition), i.e. young rabbits with lower body condition scanned less. We suggest that juveniles with low body condition were trading off vigilance against feeding to maximise their growth. In contrast, there was no significant correlation between body mass and vigilance in adult females. Adult females increased scanning rates during late pregnancy, which might constitute a behavioural compensation because of their lower capacity to escape predator attacks. In addition, adult females with low social ranks scanned more than high ranking individuals, likely because of their higher risk of attacks by conspecifics. In summary, our results highlight various individual characteristics that influence vigilance behaviour in European rabbits.

Abstract: ABSTRACT
Several studies in behavior have focused in some way on how groups of prey gather and use information about predation risk. Although asymmetries in information about risk exist among members of real groups, we know little about how such uneven information might affect individual or group antipredator decisions. Hence, we studied the use and transfer of information about the risk of predation in small flocks of wintering birds. House finches (Carpodacus mexicanus; 28 groups of three) were held in large enclosures divided into safe and risky patches. We controlled the information about risk available to each individual by conducting attacks with a model hawk that was visible to only a single (informed) bird. Repeated attacks on a single individual did not reduce the amount of feeding by other birds in that patch, although the time to resume feeding after observing a response to an attack event was somewhat longer than after a no attack event. These results suggest that informed individuals impart some information to naive (uninformed) birds, but this effect was not strong. In fact, the frequent return of informed individuals to feeders after observing uninformed individuals feed suggests that finches relied more on public information regarding safety than their own personal information in deciding when to feed. Group patch choice appeared to be based on a majority-rules decision, although an effect of dominance status was apparent. Our results suggest that subordinate flock members may exert a large influence over group decision-making by acting as spatial 'anchors'.

Abstract: Abstract Horse flies (Tabanidae) on and around feral ponies in harem groups were counted at Assateague Island National Seashore, Maryland, U.S.A., between June and August 1985. Harem stallions attracted the most flies; adult mares showed intermediate fly numbers, while few flies landed on foals under any circumstances. The use of thermal and chemical cues by flies selecting a host may have helped create this disparity. When flies were abundant, ponies reduced spacing within the group. Ponies in larger groups suffered from fewer flies than ponies in smaller groups. There was, however, no evidence that ponies merged into larger groups in response to fly harassment, suggesting that biting flies play little role in structuring pony social organization.

Abstract: An understanding of patterns of leadership during grazing movements is important where the management of grazing cattle is concerned. This paper describes the leadership displayed by grazing cattle by recording the spatial relationship (grazing style) among herd members as the group progressed slowly through a field. Grazing style was divided into “A”, “B” and “C”, meaning following, independence and leading, respectively. The results revealed the following features: (1) the frequency distributions of grazing style and grazing formation used by the herd varied with the seasons; (2) the individual animal variation in grazing style did not fundamentally change with the seasons; (3) there was negative linear correlation between Styles A and C and between Styles A and B. The more any cow followed the grazing movement, the less likely it was to lead the grazing movement or to be independent. Styles C and B tended to be positively related; (4) high, medium and low ranking animals in social dominance showed tendencies to behave in Styles C, A and B, respectively; (5) grazing style and weight gain were not clearly related; (6) the cows that tended to lead, be independent or follow less, tended to get out of their paddocks. The observations suggested (1) that the leader-follower-independent relationship, although modified in each season, did not vary fundamentally, (2) that the active movement of high ranking animals and the independent movement of low ranking animals governed the voluntary formation in grazing, and (3) that as grazing cattle that behaved in a single group and did not escape from their paddock were much easier to manage, the grazing style that expressed these characteristics was one of the significant indices for management of grazing cattle.