Fifty-one European hares Lepus europaeus Pallas, 1778 were monitored during at least one month by radiotracking in an intensively farmed landscape. The mean home range size of 21 hares monitored during at least six months was about 100 ha. During summer and autumn, seasonal home range size and the mean distance between fixes did not reveal any difference in the use of space between sexes or between age classes. However, according to the shifts of monthly resting range centres, females seemed to be more sedentary than males. The night-time activity range was often larger than the daytime resting range and partly or totally overlapped it although resting and activity locations were rarely the same. Hare movements did not show any important changes in response to crop harvesting or shooting.Office National de la Chasse, Saint Benoist, 78610 Auffargis, France

a b s t r a c tDespite the importance of conservation and management of the European hare, a game species that has declined throughout Europe, little is known about its natal dispersal process. To date, only one radiotracking study in a mixed cropping-farmed landscape provides a fine description of the dispersal pattern of this species. The study shows in particular a negative density dependence dispersal, juvenile hares dispersing more in a low-density hunting zone rather than in a high density non-hunting zone. Unfortunately, the effect of conspecific density on dispersal remains ambiguous due to the confounding effect of hunting. To provide more insight into the influence of conspecific numbers on the dispersal propensity in hares, we renewed the study in a harvested high density population.Our results confirmed the known sex-biased and age-related dispersal in this species but we did not find any effect of the birth site density on either the propensity to disperse or the distance moved in juvenile hares. Overall, the dispersal rate and bias were equal to those previously found in the high density non-hunting zone, where density was almost the same as in our population even though hunting pressure differed. Our results emphasize that natal dispersal is a ubiquitous feature in this species, which may respond more to density than hunting.

Despite their pest status in numerous areas throughout the World, the populations of European rabbits (Oryctolagus cuniculus) have strongly decreased in South Western Europe since the mid-20th century. Such a decrease constitutes a major threat on top predators and calls for a better understanding of its mechanisms to provide suitable management responses. Infectious diseases have been invoked as the main responsible factors, but they cannot by themselves explain the magnitude of this decrease. Habitat fragmentation may indeed act as a synergetic factor, and habitat use studies are needed to better understand the impact of fragmentation on rabbit population dynamics. We investigated the variability of home range size with respects to age, sex and season in three wild populations of rabbits using telemetry. Home ranges were smaller in the highest density populations (7333 and 6878 vs. 20,492 m 2 ) suggesting differences in habitat quality between the populations. In addition, home range sizes were larger during the reproductive season for both sexes, and adults tended to have smaller home ranges than juveniles. Clearly, the home range sizes reported here were smaller than those previously reported in rabbits.

Behavioral ecologists have often assumed that dispersal is costly mainly because of unfamiliarity with traversed habitats during dispersal and energy costs of the movement per se; thus, dispersers that have successfully settled should experience survival rates comparable to those of philopatric individuals. In this paper, we tested that hypothesis using 152 radio-collared European hares in a harvested population. We developed a multi-event capture recapture model, combining telemetry data and recoveries and separately modeling the foray probability, the settlement probability, and the permanent dispersal probability. The parameterization introduced here raises the possibility of separately testing effects on survival and dispersal probabilities at each stage of dispersal (departure, transience, and settlement). In accordance with our expectations, we reveal that dispersers incur higher mortality risks during transience and the early settlement period than philopatric individuals or settled dispersers. We also found that dispersers suffer from higher risks of being shot. Those results illustrate that unfamiliarity with the habitat during transience makes dispersal costly and that settled dispersers may enjoy survival rates comparable to those of philopatric individuals. Surprisingly, we also found that individuals have a higher probability of foraying during the hunting season. We suggest that hunting and related disturbances increase dispersal costs both by increasing mortality risk during transience and (perhaps) by increasing movement rates. We emphasize the need to take human pressures into account as factors that may drive the demographics of movements in populations.

The role of maternal antibodies is to protect newborns against acute early infection by pathogens. This can be achieved either by preventing any infection or by allowing attenuated infections associated with activation of the immune system, the two strategies being based on different cost/benefit ratios. We carried out an epidemiological survey of myxomatosis, which is a highly lethal infectious disease, in two distant wild populations of rabbits to describe the epidemiological pattern of the disease. Detection of specific IgM and IgG enabled us to describe the pattern of immunity. We show that maternal immunity attenuates early infection of juveniles and enables activation of their immune system. This mechanism associated with steady circulation of the myxoma virus in both populations, which induces frequent reinfections of immune rabbits, leads to the maintenance of high immunity levels within populations. Thus, myxomatosis has a low impact, with most infections being asymptomatic. This work shows that infection of young rabbits protected by maternal antibodies induces attenuated disease and activates their immune system. This may play a major role in reducing the impact of a highly lethal disease when ecological conditions enable permanent circulation of the pathogen.