Cooperative Fish and Wildlife Research Units Program: Texas
Education, Research and Technical Assistance for Managing Our Natural Resources

The Mexican spotted owl (Stix occidentalis lucida) is protected as a threatened species under the federal Endangered Species Act, and the species is distributed irregularly due to the patchy distribution of its habitat. Texas Parks and Wildlife Department lists the owls as threatened and a S1B species, indicating it is critically imperiled in the state because of extreme rarity or other factors. Currently, the species’ known distribution in Texas is based primarily on a few documented observations at isolated locations in the Davis Mountains and the Guadalupe Mountains. No focused effort has been made to assess the true distribution and habitat associations of Mexican spotted owls in Texas. The primarily privately owned and rugged landscapes with habitat suitable for the species, and the fact that conventional surveys must be done at night and are time consuming (i.e., expensive), have rendered conventional surveys very challenging in the Trans Pecos region. We are initiating a study to assess the distribution of Mexican spotted owls in Texas by using passive audio monitors (PAMs) to sample the nocturnal hours for Mexican spotted owl vocalizations on public and private properties in the Trans Pecos allowing wildlife researchers to access to their properties. Owls announce their presence and breeding territories by species-specific, identifiable, vocalizations at night. Each PAM will be programmed to record during the Mexican spotted owl breeding season (~February – April). Each PAM will then be retrieved, data downloaded and analyzed for detections of Mexican spotted owls. Our final product will help address knowledge gaps for the Mexican spotted owl distributions in Texas and serve to facilitate informed listing, conservation, and management planning, and serve to guide future research on the species.