Ultrasonic sound production has recently been discovered in hummingbirds. Behavioral and acoustic studies suggest that these ultrasonic sounds may function in communication. To test this hypothesis, the researchers propose to determine whether or not hummingbirds are able to perceive ultrasonic sounds (above 20 kHz). If so, further behavioral studies will evaluate the communicative role of ultrasonic signals. Ultrasound perception will be assayed by monitoring hummingbird heart rate responses to presentations of ultrasonic signals. Establishing the use of ultrasound in hummingbirds would demonstrate sound production and auditory sensory abilities previously unknown in any avian species, and would be the first step towards understanding how birds use ultrasound.
Basic research of mammalian ultrasound has influenced the development of ultrasound and sonar use across such fields as medicine, engineering, manufacturing, intelligence, and communication. Many features of mammalian ultrasound exceed the sophistication of artificial ultrasound, including the ability to manipulate and respond to changes in signal parameters, use binaural processing with separate transmitter and receivers, and compensate for the Doppler effect due to relative movement between transmitter and receiver. Much of the current applied ultrasound research is directed towards developing effective replications of mammalian ultrasound. Examination of a new animal group, with a distinct ecological niche and evolutionary history, may provide innovative design features not present in mammalian ultrasound systems, which may be adapted for human applications.
