Age-specific reproductive behaviours in male roe deer Capreolus capreolus

The behaviour of active male roe deer Caprealus caprealus Linnaeus, 1758 was studied in a wild population on Storfosna island (Norway), during the pre-territorial and territorial seasons (February-August) of 1994. Observed behaviours were grouped in seven categories (mating, aggression, display, marking, vigilance, moving and maintenance), and the proportion of time spent in each behaviour by three age classes (yearlings, subadults and adults) was compared. Time spent in each behaviour varied significantly between months for all male age classes. From February to August, time spent in maintenance decreased, while time spent in vigilance increased. The time spent in mating increased both in adult and subadults but did not vary significantly for yearlings throughout the months. When comparing age classes within a month, there were no significant differences in time spent in each behaviour. Surprisingly, adult territorial males did not invest significantly more time in mating, with respect to yearlings and subadults. This may be consistent with the oligogynous mating system of roe deer, in which the reproductive success is divided amongst several years and their territoriality, which could be a tactic to reduce the competition for mating.