Western burrowing owl (Athene cunicularia hypugaea) populations in southern California have significantly declined, prompting a reassessment of their distribution. In this study, we employed passive acoustic monitoring using Audiomoth Autonomous Recording Units (ARUs) to detect owl vocalizations at five sites in San Diego County. Our objectives were to optimize ARU setups for detection, enhance the accuracy of burrowing owl call classification using BirdNET-Analyzer, and validate acoustic data through in-person surveys. We deployed ARUs at the center of 250x250-meter grids mapped across each site (RGCB, n=8; OBPR, n=3; RJER-Field 1, n=3; RJER-Field 7, n=3; LS, n=9). Additionally, ARUs were placed at four active nests at one site (RGCB). All ARUs were configured with a 32 kHz sample rate and medium gain, set to record at 4-hour intervals during dawn and dusk. The subset of ARUs deployed at nests recorded continuously to determine whether sampling only at dawn and dusk would yield comparable data to continuous recording, reducing the need for extensive data collection. By integrating passive acoustic monitoring with in-person surveys, this research contributes to the development of a regional burrowing owl monitoring plan and enhances our understanding of their ecology in southern California.