Expanding development, altered hydrology, and invasive vegetation have increased fire risk in many sensitive habitats. The Santa Clara River in Ventura County, California, is one of the region’s last relatively intact riparian ecosystems and provides critical breeding habitat for several at-risk bird species. In November 2024, the Mountain Fire burned nearly 20,000 acres, including extensive portions of the river valley, likely amplified by the invasive Giant Reed (Arundo donax), whose dense and aggressive growth can suppress native riparian vegetation. Using autonomous recording units (ARUs), we assessed how bird vocal activity responded to fire. Data was collected in the summers of 2023 (pre-fire) and 2025 (post-fire), and daily call rates were estimated using the BirdNET algorithm. Sites were classified as burnt or unburnt; the call rates of seven focal bird species representing a variety of feeding guilds were compared before and after the fire in each site. Most species showed significant changes in call rates between pre- and post-fire periods, except for the Hairy Woodpecker. The Least Bell’s Vireo increased its calling activity in unburnt areas and decreased in burnt areas, suggesting post-disturbance redistribution into higher-quality habitat. These findings indicate that fire strongly influences avian communities in riparian ecosystems, highlighting the importance of considering fire severity in post-fire management, restoration planning, and invasive species management.