The use of video cameras to monitor avian nests has allowed identification of key nest predator species and could potentially improve our understanding of parental nest defense. For songbirds, cameras have often shown snakes to be the most common nest predator, although video evidence of passerines successfully defending nests against snakes is lacking. We describe the first evidence of a small passerine, the Louisiana Waterthrush, successfully thwarting a possible predation attempt by a juvenile ratsnake. This recording documents rarely observed nest defense behavior and allows us to consider how this event fits within theories of optimal nest defense.