Dr. Jim Jacobi has spent the past 50 years in Hawaiʻi as a biologist specializing in mapping Hawai’i’s unique ecosystems and studying the plants and animals contained within them. Like so many of his cohort, he is a skilled naturalist, having worked on introduced rats, native insects first for the Bishop Museum and then mapping vegetation and management research projects for the Pacific Island Ecosystems Research Center of the US Geological Survey in Volcano. We talk to Jim about the evolution of tracking changes in vegetation by hand from aerial photos to the use of computer mapping and modelling. He shares with us the unique experiences heʻs had across the rugged U.S. Fish and Wildlife Service transects that traverse mountainous summits to sea, as well as the profound sorrow in witnessing the last Hawaiian honeycreeper in the wild, the Kauaʻi oʻo.