Hormonal, neuroendocrine, and behavioral mechanisms responsible for the development and expression of animal social behavior and social relationships. Current projects of my laboratory include:(a) development of preferences for pairing partners in the socially monogamous zebra finch, (b) neuroendocrine mechanisms involved in pair formation in zebra finches, (c) effect of parental rearing type on later behavior and HPA axis function in zebra finches, and (d) mating and fertilization strategies in Japanese quail. The common theme is an integrative approach aimed at understanding how function and phylogeny have shaped hormone-brain-behavior relationships.