9722735 Faaborg This Americas Program award will fund a 3-year cooperative research project between Dr. John Faaborg, University of Missouri, Columbia, and Dr. Tjitte de Vries, Pontificia Universidad Catolica del Ecuador. They will conduct population studies on genetics and ecology on cooperative polyandry in Galapagos hawks. Cooperative polyandry, where each female has several mates, but each male has only one, is a useful system for studying the evolution of sociality in vertebrates, and evaluating the conflict of interests between the sexes. "Cooperative" polyandry of this type is rare, having been described in only seven species besides Galapagos hawks. In order to understand the evolution of this form of cooperative breeding, there is need to know the degree of relatedness of individuals breeding in groups, the actual patterns of parentage among polyandrous males, and the lifetime reproductive success of males and females living in groups and those living in pairs. The investigators propose to monitor more than 100 social groups per year to measure reproductive success as a function of group size and compare distribution of reproductive success in males and females. They will do survey work in four islands populations in order to have both high and low habitat diversity. The proposed work most likely will generate some interesting and provocative ideas about how ecological forces may affect mating systems. ***