The Brazilian free-tailed bat (Tadarida brasiliensis) is the most abundant mammal in North America. Despite their abundance, little research has been done on their diets and ecological impact on the edges of their range in California. Recent advancements in DNA metabarcoding techniques in the last two decades have provided huge leaps in dietary studies providing a more comprehensive and ethical approach to this important avenue in bat research. This project employed a multi-faceted approach to studying the diets of T. brasiliensis in California and reveals unprecedented information about their dynamics across seasons, locations, and after a large wildfire disturbance. Bat fecal samples were collected at Big Chico Creek Ecological Reserve (BCCER) and the Chico State University Farm (CSUF). A metabarcoding analysis performed by the Species from Feces lab at Northern Arizona University (NAU) revealed significant differences in the diet profiles depending on location, season, and after fire disturbance. Dietary patterns showed connections towards seasonal insect abundance patterns, pest species at CSUF, and opportunistic insects that colonize following large wildfire disturbances. These results contribute crucial insights to how this species changes its diet depending on environmental factors and provides practical information useful for applications in bat conservation and sustainable agriculture.