I am interested in the mechanisms by which female birds program their offspring's phenotype. The steroid composition of a given egg reflects the mother's endocrine status for the week preceding lay, and, since plasma levels of corticosterone increase in response to stress, eggs produced by females under stressful conditions are expected to have higher levels of corticosterone. Developmental exposure to corticosterone induces persistent,  lifelong changes in physiology and behavior; this provides a hypothetical mechanism by which maternal environment programs offspring phenotype. I will test for corticosterone-mediated programming in Japanese quail and White Leghorn chickens by experimentally elevating corticosterone in laying hens, and quantifying stress responsiveness in embryonic, juvenile, and adult offspring.