The “Night Wings” (Bats) of Southern Alameda County - East Bay Regional Park District

Bats perform substantial ecological services, including insect consumption, pollination, seed dispersal, and nutrient cycling. Their low reproductive rates and sensitivity to human disturbance makes bats vulnerable to a variety of threats including habitat loss and fragmentation through weather disasters, pesticides, toxic wastewater, wind farm development, and the fungal white-nose syndrome. With the help of the “Bat Brigade” wildlife volunteer group, the East Bay Regional Park District (EBRPD) conducted a 9-year study (2017 to 2025) of bat distribution, abundance, and calls per hour at three locations in southern Alameda County. A total of 58 bat exit, and acoustic surveys were conducted periodically between April and July at Sunol Wilderness Regional Preserve, Lake Del Valle Regional Park, and Camp Arroyo Regional Recreation Area. The study confirmed the presence of 7 genera and 10 species of bats, including three California Species of Special Concern: The Pallid Bat (<i>Antrozous pallidus</i>), Townsend’s Big-Eared Bat (<i>Corynorhinus townsendii</i>)<i>,</i> and the Western Red Bat (<i>Lasiurus blossevillii</i>). Additionally, the acoustic sampling detected the following species in order of abundance: Yuma Myotis (<i>Myotis yumanensis</i>), Mexican Free-Tailed Bat (<i>Tadarida brasiliensis</i>), and California Myotis (<i>Myotis californicus</i>). Lastly, more than 1,000 volunteers contributed over 5,000 hours of supervised service annually, and this effort demonstrates the tremendous energy that community scientists can bring to a wildlife conservation program.