Behavioural changes of 20 radio-tagged European hares Lepus europaeus were analysed in relation to the harvesting of summer crops under intensive large-scale farming in northeastern France. Focal sampling was also performed to estimate activity budgets and to analyse vigilance sequences according to group size and pre/post-harvest factors. Night-time ranges were 40% larger than day-time ranges; the total home range size was 190 ± 53 ha. Both night-time and day-time range sizes were independent of the pre/post harvest factor, although pre-harvest range centres shifted after harvest and the overlap areas were avoided. Habitat use within ranges was independent of the day/night and pre/post harvest factors, and hares made a larger use of cultivated areas than expected by chance (P < 0.01). Landscape diversity in the home range of hares was lower after harvest than before, but the animals did not maximise their access to crop diversity. Time spent scanning was negatively correlated with group size (r = -0.32, P < 0.005) and vigilance levels averaged lower after than before harvest (P < 0.05). Inter-scan intervals (ISIs) were non-randomly distributed and periodicity in the scanning behaviour was identified using spectral analysis. Hares foraging alone displayed a stronger cyclic pattern in vigilance sequences (i) than hares foraging communally (P = 0.043), and (ii) after than before harvest (P = 0.047). These results were analysed in connection with increased predation risks and shifts in resource distribution.