The "polygyny threshold" model: a reassessment

Abstract

The "polygyny threshold" model, first outlined by G. H. Orians in 1969, can be viewed as a functional explanation for the maintenance of polygyny in a population by natural selection. This model has been particularly associated with resource defence polygyny in passerine birds. Thus it is used here to generate some quantitative predictions concerning how the females in such a passerine population should distribute themselves for breeding over a series of territories defended by males, some of whom become polygynous as a result. Some of the assumptions underlying the model are examined and the predictions are tested using both new field data and some taken from the literature.