Territoriality as a mating strategy in red deer

The mating behaviour of red deer stags, Cervus elaphus, has been extensively described as harem defence. However, it appears that territoriality may be chosen as a mating strategy when certain conditions are met. In a study area in southwestern Spain, early on in the rut, about 58% of adult males established territories in preferred areas, defended the territory against other males even in the absence of females, and courted females only within territorial boundaries. The mean territory size was about 2.3 ha. The later a male settled on his territory during the rut the fewer the females he was able to keep. The preferred areas where males established territories were also extensively used by females even before the start of the rut. The number of females per ha before the onset of the rut was positively correlated with the cumulative number of hinds that each male kept later on. Hence the reproductive success of males was largely influenced by the location of their territory. Such intensive use by females of a highly productive area for feeding and daily passage in an otherwise low-resource environment appears to promote the defence of territories located in the richest area. This paper provides the first evidence for territorial defence of mates in red deer and may contribute to the understanding of the dynamic nature of mating behaviour in ungulates. Reproductive strategies in male ungulates are mainly designed to maximize their access to receptive females. Gosling (1986), in a review of reproductive strategies of different antelope species, showed that males can adopt a variety of strategies including following a group of females over their foraging range or staying in one part of the females' range and defending it against other males. The average reproductive success derived from adopting one strategy or another depends mainly on the ecological factors that influence the social and spatial behaviour of females. A considerable lability of mating systems is thus expected between populations of a given species living under different environmental conditions (Emlen & Oring 1977). Although there is little evidence for intraspecific variability in ungulate mating systems, recent reports suggest that between-population variation may be greater than usually assumed (see Gosling 1986 for antelopes; Rubenstein 1986 for horses and zebras; Schaall & Bradbury 1987; Pemberton & Balmford 1987 for fallow deer, Dama dama; Knight 1970; Geist 1982 for North American elk, Cervus canadensis). Rutting cervids are reportedly non-territorial, definite evidence of territoriality in the family being available only for the roe deer, Capreolus capreolus 0003-3472/90/070079 + 10 $03.00/0 9 79 (Kurt 1968; Bramley 1970) and the sika deer, Cervus nippon (Miura 1984) whereas the general tendency for most species is for males to mate by joining a group of females and following them over their foraging range (Btitzler 1974; Owen-Smith 1977). Nevertheless, there are some early suggestions of territoriality in cervids, including red deer, Cervus elaphus. Thus, Graf (1956) indicated that territoriality in the family Cervidae had apparently been overlooked. He predicted that evidence for territoriality would be forthcoming when more species had been studied. Burkhardt (1958) considered the existence of territoriality and scentmarking behaviour when observing a population of red deer in Switzerland but provided no data to demonstrate it. Reproductive behaviour of red deer has been extensively studied on Rhum (Scotland) by T. H. Clutton-Brock and colleagues (CluttonBrock et al. 1982). In the early rut, males move to traditional rutting grounds, attempt to form harems and, once associated with hind groups, they move as their harems do to new feeding areas or to sheltered positions. Although Darling (1937) seemed to recognize some territorial behaviour by rutting stags, further studies on Scottish red deer demonstrated only a tendency to concentrate rutting activities in particular areas, mainly for 1990 The Association for the Study of Animal Behaviour 80 Animal Behaviour, 40, 1 prime stags, but without any defence of the terrain in the absence of a harem (Lincoln et al. 1970; Lincoln & Guinness 1973; Gibson & Guinness 1980; Clutton-Brock et al. 1982). Nevertheless, information from other populations, in particular those inhabiting markedly different habitats like those of the Mediterranean region, may bring a new perspective to the adaptive plasticity of mating behaviour in the species. Our aim in this study is to investigate whether territories are held by rutting males in a population of red deer living in Dofiana National Park, in the extreme southwestern edge of the species' European range.