The concept of tradeoff between current and future reproduction ("cost of reproduction") is central to life history theory, and so to our understanding of the evolution of reproductive characteristics. For birds, existing empirical demonstrations of this tradeoff are all flawed by poor choice of experimental species, short-term experiments, and drastic manipulations. Hence a fundamental tenet of evolutionary theory remains to be tested rigorously in this group. This proposal describes an experimental test of the hypothesis that the cost of reproduction is a significant selective agent in the evolution of reproductive rate. Specifically, the study can test the hypothesis that adding only one additional offspring to a brood imposes a cost of reproduction large enough to impose natural selection against that experimental brood size. By using an appropriate study species yielding large samples and adopting a long-term perspective this study avoids the flaws of previous work in this area. This study builds on 10 years of field work by the principal investigator with the study species on related problems. %%% Research of this type, in addition to being of fundamental importance to theoretical and empirical population biology, should have positive bearing upon such emergent modern themes as species conservation and biological diversity. As well it may yield information useful in the commercial breeding of fowl for food.
