New insights into little penguins’ sensitivity to noise

Researchers from Curtin University have used cutting-edge imaging technology to shed light on the hearing sensitivity of Australia’s little penguins and the danger of marine noise pollution.

This study is the first to detail how little penguins, also known as fairy penguins, perceive sound both in air and underwater. The research, titled “Sound reception and hearing abilities in the little penguin (Eudyptula minor): First predicted audiograms in air and underwater,” is published in the journal Royal Society Open Science.

Study leader Dr Chong Wei, from the Curtin Centre for Marine Science and Technology, said little penguins were particularly vulnerable to human-caused noise because their habitats often overlapped with shipping lanes, recreational activities and coastal developments.

“Ocean noise pollution is increasing steadily and this is of particular concern for little penguins whose populations are in significant decline,” Dr Wei said.

“We know very little about how this noise affects penguins’ hearing. To address this, we created 3D digital models using microCT scans of the heads of three naturally dead little penguins on Garden Island to simulate what they might hear at different frequencies.

“The units of frequency are called hertz (Hz) and these 3D models revealed that little penguins can hear sounds over a wide range between 200 and 6,000 Hz underwater, like other diving birds such as the great cormorant.

“Ship noise typically ranges from 20 to 10,000 Hz, as does pile driving.”

Co-author John Curtin and Distinguished Professor Christine Erbe, from the Curtin Centre for Marine Science and Technology, said the research findings are valuable to marine conservation efforts.

“Continued exposure to high noise levels from passing ships and construction near the shore could increase stress and interfere with little penguins’ behaviours, such as feeding,” Professor Erbe said.

“Understanding their hearing range helps us identify potentially harmful noise frequencies and the results can inform management plans to reduce the impact of noise pollution.”