[3] She worked as a biology professor at the University of South Carolina (USC) from 1967 until her retirement as director of the W. Gordon Belser Arboretum in 2019.
She became fascinated with the outdoors though traveling with her father, a physician, and the rest of her family to remote wilderness areas [4] While attending Hunter College High School in New York City she began collecting data on the songbirds of a hardwood forest in Long Island.
She entered this project in the 1950 Westinghouse Science Talent Search and was named a finalist along with her twin sister Cynthia (Jackson) Fisher.
[8] DeCoursey helped the scientific world understand the adaptive value of the mammalian biological clocks (found within the suprachiasmatic nucleus (SCN)).
[10] This research has helped further our understanding of sleep related issues affecting humans such as jet lag or insomnia.
The arboretum is designated as an outdoor field classroom and laboratory for UofSC undergraduates, and it is also used for conducting a variety of educational outreach programs.
[11] According to an article in Scientific American, DeCoursey “spends half her work time on the restoring the arboretum and organizing class visits, and the other half on her professorial duties.” [5] Decoursey was a member of the original Organizing Committees for both the Journal of Biological Rhythms and the Society for Research on Biological Rhythms (SRBR).