Vigilance Behavior Of Semi-free-ranging Pere David’s Deer

After being kept in captivity and isolated from natural predators for more than1200years, Pere David’s deer (Elaphurus davidianus) has been reintroduced in China and now occurs in reserves where human activity is the only potential threat. Antipredator vigilance is an important component of survival for many prey animals in their natural habitat. Do deer still adjust vigilance as a function of risk after such a long period of relaxed predation pressure?In the second chapter of this essay, we did field experiment to explore the question above. Here, we examined vigilance levels in Pere David’s deer groups as a function of group size, sex and level of human disturbance. The results showed a significant negative influence of group size on vigilance in all-female groups but not in all-males or mixed-sex groups. In rutting season, males compete with one another and harass females, and we argue that vigilance is partly aimed at threatening males and that such vigilance increases with group size. This explains why overall vigilance did not vary with group size for males in general and for females in mixed-sex groups. Vigilance increased in more disturbed areas. The results indicate that despite relaxed predation pressure over centuries, Pere David’s deer can still adjust antipredator responses as a function of perceived risk, which may become useful in the rewilding programme now under way for this species in China. In field observation, we found that cattle egrets (Bubulcus ibis) and Pere David’s deer often form mixed groups. Then do cattle egrets help Pere David’s deer to alert?In the third chapter of the essay, we did field experiment on the interspecific relationship of Pere David’s deer and its associate species. In this study, the foraging benefits cattle egrets got from the association were measured mainly from three aspects, the total foraging earning, the expenditure per capture and the capture success rate. Apart from the foraging benefits, the vigilance advantage was also taken into account. The influence exerted on deer by cattle egrets on vigilance and parasites-removal was analyzed too. The results showed that, cattle egrets can spend less time and steps to earn more pecking chances when foraging with deer and the capture success rate significantly increased. Meanwhile, their vigilance frequency dramatically decreased. In contrast, cattle egrets did not bring vigilance-or parasite-related benefits to deer.All these basic researches on vigilance behavior of Pere David’s deer help us to further understand their vigilance strategies in semi-enclosure. By exploring what natural and artificial factors will influence the vigilance behavior of Pere David’s deer, we provide scientific reference for improvement on the management of the reserve. The vigilance behavior of Pere David’s deer is closely related to the extent of human disturbance. To master the law is helpful to more rationally design tourism activities, so as to maximize visitors’tour experience under the premise of minimizing the disturbance on Pere David’s deer’s normal life. Moreover, researches on Pere David’s deer in semi-enclosure help us speculate their anti-predation mechanism in pure wild environment which means significant to the rewilding project ongoing. Meanwhile, exploring the relationship between Pere David’s deer and their associate species is conducive to the full consideration of the needs of different species in the conservation and then comprehensively protect their symbiotic habitats.