The kin-facilitation hypothesis for red grouse population cycles: territory sharing between relatives

The regulatory effects of spacing behaviour on population size are the basis of the kin-facilitation hypothesis for population cycles in red grouse. The process of territory sharing, between neighbouring relatives aggregated in kin clusters, is one of the mechanisms postulated to affect spacing behaviour and, through it, population density. We assume perfect philopatry and maximal cooperation, and suppose that the degree of contact between relatives and their ability to recognize kin are the only important factors deciding the amount of territory sharing. These two components are independently quantified as functions of kin cluster size. The resulting relationships are combined to produce a response function describing the effects of cluster size on minimum territory size, and hence carrying capacity.