Abstract DBI 9750301 Lauren V. Riters This action funds an NSF Postdoctoral Research Fellowship in Biosciences Related to the Environment for 1997. This fellowship provides an opportunity for the Fellow to gain additional scientific training beyond the doctoral degree and to pursue innovative and imaginative into the fundamental mechanisms underlying the interactions between organisms and their environment at the molecular, cellular, organismal, population, community and/or ecosystem level in any area of biology supported by the Directorate for Biological Sciences of the National Science Foundation. Each fellowship supports a research and training plan to be carried out in a sponsoring laboratory. The research and training plan for this fellowship is entitled "Neuroendorcrine control of seasonal singing in starlings." For many birds, lengthening days lead to elevation of testosterone levels and changes in the area of the brain necessary for singing. But birds also sing during shortening days when the level of testosterone and the brain regions required for song are unchanged. This study uses starlings to investigate how changes in day length modifies the responsiveness of the brain to testosterone and how environmental factors affect the brain to produce seasonally relevant behavior.