DENSITY-DEPENDENT CHANGES IN THE SPACING BEHAVIOR OF FEMALE KIN IN RED DEER

1. In some social mammals living in matrilineal groups, complete dispersal from the natal area is unusual, even when population density is high and reproductive performance depressed. 2. Female red deer on the Island of Rum (Scotland) aggregate in unstable matrilineal groups. The degree of spatial association ('proximity') between individuals increases with their degree of relatedness as well as with their dominance rank but declines with increasing age. 3. As population density doubled between 1974 and 1983, the degree of spatial association between female kin declined. At all ages, individuals spent less time close to their relatives and more with unrelated animals when population density was high. 4. These results emphasize that in mammals with fission/fusion societies like red deer, dispersal is a gradual process and that it does not necessarily involve the total abandonment of the natal area by individuals as they disperse.