Type: report

Article abstract: Twenty-three of the 45 bat species known to occur in North America have been documented in San Diego County over time. Although historical information exists for many of these species, there is very little information regarding their current status and distribution. In the past several decades, there have been extensive changes to the coastal plain, inland valley, and foothill areas as a result of rapid population growth and associated urban expansion. Many native habitats and species appear to have declined or have been extirpated from these areas. In response, a network of lands for preservation of native species is currently being planned and executed throughout the county as part of the Natural Community Conservation Plan. We are currently conducting a 3-year survey of San Diego County Multiple Species Conservation Program (MSCP) area lands using acoustic techniques, spotlights, and mist nets to detect and identify bats at foraging sites. We are supplementing this effort with surveys of selected potential roost sites such as caves, tunnels, bridges, and abandoned buildings using acoustic, visual, and capture techniques. It is our purpose to provide current information on species' ranges and seasonal activity patterns in the San Diego County MSCP area. This data will be valuable for comparison of current versus historical distribution of bat species, provide baseline data for biological monitoring of the NCCP preserve system, and aid in future conservation planning. Preliminary data are presented.