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Abstract

in a predictable environment, variation in quality among breeding sites should select for mechanisms by which animals can increase their chances of ending up in a good site. In this paper, I develop an optimality model that explicitly considers the use of information by first-time breeders for selection of local breeding habitat. The model compares the expected fecundity in the first breeding season of two strategies. One strategy (natal dispersal) allows individuals to prospect (i.e. gather information) for good future breeding sites at a cost that increases with their prospecting activity. Individuals using the other strategy (natal philopatry) have complete information about their natal breeding site at the time of birth and they do not prospect. Allowing prospecting activity and age at first breeding to evolve, the model yields several qualitative predictions about how natal dispersal within a population should evolve under different environmental (prevalence of good sites, predictability of site quality among years) and demographic (pre-breeding survival rate) conditions. Natal philopatry is expected to prevail in all environments when pre-breeding survival is low, while increasing pre- breeding survival should allow natal dispersal to dominate in an increasing range of environments appearing first in unpredictable environments.