The echolocation was collected with a Binary Acoustic Technology (BAT) IFR-IV Bioacoustic detector. The call was identified as a bat by myself and Jim Dines of the Natural History Museum of Los Angeles County. The species was identified as a Mexican-free tailed bat with Sonobat software. The Free-tailed Bat and the Myotis Bat we just documented are new records for Exposition Park. They join just one other bat species previously documented here based upon prepared specimens in the museum’s mammal collection: the Hoary Bat.