Roe deer can be active throughout the 24-hour period, but the main peaks of activity occur at dawn and dusk (4). They are either solitary or occur in small mixed groups, and in winter large groups may form to feed together (4). They have a broad diet, which varies depending on the time of year, and includes the leaves of deciduous shrubs and trees (4), cereals, weeds (3), acorns, fungi, conifers and ferns (3).
The breeding season or 'rut' occurs from mid-July to mid-August (2). During this time, males (bucks) become highly aggressive and defend their territories vigorously (2). Fights between males often ensue, two males lock antlers and push and twist (4); these fights can cause serious injuries and even death (2). The winning buck may then mate with a female; courtship involves the buck chasing the female (doe) for some time until she is ready to mate (2). Although mating occurs in August, the fertilised egg does not start to develop until the end of December or early January (3); the roe deer is the only hoofed animal to have this 'delayed implantation' (4), which is thought to be an adaptation to prevent births occurring during the harsh winter (2). Between one and three kids are produced in May and June (3), but twins are very common (4). The young are left alone during the day for the first six weeks of life; their spotted coats help to camouflage them (4), although mortality from predation can still be high (3). After this time they stay by their mother's side (4). Both sexes disperse, but females tend to stay closer to their mother's range than males (3). Sexual maturity is typically reached at around 14 months of age (3).