High altitude echolocation of insects by bats

Summary The orientation sounds of many bats, almost certainly belonging to the genus Tadarida, were recorded at altitudes of 100 to 300 m above the ground by means of an ultrasonic radio microphone. Both in North Queensland, Australia, and in southern Utah and Nevada, USA, bats were often more numerous at 200 to 300 m than near the ground. Rapid increases in pulse repetition rate often indicated that these bats were actively hunting flying insects. The absence of clutter at high altitudes may significantly facilitate the detection and capture of insect prey.