Neural Mechanisms of Avian Echolocation
Different groups of animals including vision-impaired humans use a biological sonar system (i.e. echolocation) instead of vision for navigation. They actively produce sounds and analyze the echoes reflected by surrounding objects to gain knowledge about the objects’ locations, three-dimensional shape and surface structure.
The only non-mammalian animals that are known to use biosonar belong to two avian groups, the Oilbirds (Steatornis caripensis, Caprimulgiformes), which are endemic to South America, and several species of Indoaustralien swiftlets (Aerodramus and Collocalia, Apodidae). While biosonar behavior and its underlying neural correlates are widely investigated in bats and toothed whales, data on echolocating birds is rare. In contrast to the ultrasound signals of bats and whales, the sonar signals of echolocating birds are in a frequency range audible to humans, and the calls’ spectrotemporal structure is similar to that of sonar signals used by blind people.
Recently, the use of echolocation became more and more common amongst vision-impaired persons. Yet, although researchers started to investigate the mechanisms that allow humans to navigate by using echolocation, we are still far from understanding every detail. Up to now, findings from research on human echolocation were mainly compared to data collected in bats. However, even though the same physical principles may apply during echolocation by bats and humans, bats show behavioral, anatomical, and neural specializations for biosonar, which are not found in humans. Echolocating birds have a less sophisticated biosonar system than bats and use sonar signals similar to those of blind humans. Therefore, studying the biosonar behavior and the underlying neural correlates of these birds might be advantageous to better understand the mechanisms of human echolocation.
This project is done in collaboration with Prof. Paolo Piedrahita (Escuela Superior Politécnica del Litoral, Ecuador).