A two-year field study will examine the ecological and evolutionary determinants of cooperative polyandry in populations of the Tasmanian native hen (Tribonyx mortierii, Rallidae). This unusual social system, in which two or more males pair with a breeding female, occurs in very few bird species. Some birds in a population do not exhibit this mating pattern, but instead show monogamy, or polygyny. This postdoctoral fellowship effort will investigate the factors that determine the extent to which males care for the young, account for the occurrence of polyandry in these birds, and influence mating pattern variation. The study encompasses investigations of parental investment, paternity, reproductive tactics, and social relationships in a previously studied bird. However, this species has never been subjected to such concentrated and prolonged study, which includes trapping and marking, observation, and limited experimental field manipulations. The Fellow's host institution in Australia will be the University of New England.
