Resource Partitioning between Sexes in White-Tailed Deer

Abstract

We tested resource partitioning between sexes of white-tailed deer (Odocoileus virginianus) by analyzing spatial and temporal distribution of each sex on the George Reserve, Michigan. Mean overlap of sexes by season was approximately 56%. Overlap was greatest during severe weather in January and least during fawning in May. Areas of concentration of each sex shifted between seasons. Females showed greater dispersion than males. There was differential use of habitats by the sexes at some seasons. Differential use of habitats was greatest when spatial overlap of sexes was highest, and vice versa. Differential use of space and habitats, in conjunction with differences in diets and diet quality, help explain the apparent lack of competition between sexes. J. WILDL. MANAGE. 53(2):277-283 An unexpected outcome of manipulations of the enclosed white-tailed deer population on the George Reserve, Michigan, was that recruitment rate was negatively correlated with number of females, but was independent of the number of males (McCullough 1979). Social factors could be ruled out because recruitment responded differently at the same population size before and after an overshoot of carrying capacity following the initial introduction (McCullough 1984:216-217), and this result was repeated in a recent overshoot experiment (D. R. McCullough, unpubl. data). Given that resources were the limiting variable, one would have expected that density per se, irrespective of sex, would be important because resources are depleted by the feeding of both sexes. Apparently, resource partitioning between sexes must exist on the George Reserve if competition for resources among females is more direct than competition between females and males. Studies of sexual segregation in ungulates have emphasized the hypothesis of reduction of competition for resources first put forward by Darwin (1871) and elaborated by Selander (1966, 1972) for birds. Spatial segregation of the sexes in the nonbreeding season is well known in ungulates (Darling 1937, Dasmann and Taber 1956, Welles and Welles 1961). Also, differences in diets between sexes have been reported by Takatsuki (1980) in sika deer (Cervus nippon), and Shank (1982) in bighorn sheep (Ovis canadensis). Jackes (1973), Watson and Staines (1978), and Bowyer (1984) reported that females occupied better habitat than males, and Staines and Crisp (1978) and Staines et al. (1982) reported that females selected more nutritious for-