Big brown bats recorded on thermal camera with audio

This recording was captured of big brown bats on August 11, 2022 in Murrysville, PA using a Hikvision DS-2TD2636-15 thermal IP camera at 720P combined with a Pettersson Ultrasonic Detector model D 200 for audio. The D 200 was set at 25.5 kHz, which is the strongest frequency we found the big brown bat echo location range. At this frequency we can detect the big brown bat out to 200 yards. The D 200 brings the echo location calls down into a frequency humans can hear.

We would like to thank Dr. Jim Kella, professor of Ornithology at Saint Vincent College in Latrobe, PA for lending us the D 200 Ultrasonic Detector for this video.