Rare bird activity tracked with remote ‘soundscape’ monitoring on Japanese island
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Using a system of audio monitoring stations, researchers have been able to track bird activity on Okinawa Island, Japan.
The study is part of the Okinawa Environmental Observation Network Churamori Project, a partnership between researchers and citizens which aims to better understand the environment of Okinawa Island.
The tropical and subtropical islands making up Okinawa are home to many species of flora and fauna, many of which are endangered. These include the Okinawan Woodpecker, Okinawa Rail and Iriomote cat.
Researchers at Okinawa Institute of Science and Technology (OIST) and collaborators at the University of Leeds came together on a project to monitor the ‘soundscape’ of the Okinawan jungle: the rich collection of noises that can be heard in a particular area.
The team set up monitoring stations – which look like green boxes – across five sites in wild and urban areas. They recorded weather conditions and the natural and human-made soundscape of the island across five sites during the summer. Microphones at each site collected high-quality audio data for 10 minutes every half hour.
“Everyone knows a city sounds different than a forest, but scientists are increasingly interested in studying soundscapes in a quantitative way,” said Dr Evan Economo, head of the biodiversity and biocomplexity unit at OIST.
“How an ecosystem sounds has a lot of information in the processes occurring there.”
As the researchers listened to their audio recordings, they took into consideration the type of land cover in each site. An OIST supercomputer and sound recognition software helped the researchers hugely reduce the amount of time taken to analyse the 25TB of audio collected.
“In a previous model of ecological research, we’d have technicians in the field constantly to get this kind of data,” said Dr Nicholas Friedman, co-author of the study. “With this approach, we can make a model of how you identify birds, so we can survey more sites with less money.”
For the first time, Dr Economo and his colleagues were able to track bird activity on Okinawa using remote acoustic monitoring alone. Their data allowed them to confirm that there are more bird and other animal sounds in the least developed areas, while the most urban areas are less populated by creatures.
According to Dr Economo, noise pollution can have a disruptive effect on populations of birds, which rely on sounds to find food, mates and establish a territory.
In the future, the researchers aim to expand from five to 24 sites and to monitor a greater range of animals, including insects.