Audio 1 (AUDIO) Smithsonian Tropical Research Institute Your browser does not support the audio element. Caption Courtship song of Centurio senex slowed down 10 times and therefore transformed from ultrasound into the range audible to humans. There are short echolocation calls, interrupted by several trill sequences, audible wing beats and finally a very loud scream. This last scream is the same call that is heard at the end of Video 1 without downward transformation. Credit Marco Tschapka Usage Restrictions Credit: Marco Tschapka License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.