Listening to ecosystems: New study published using acoustic monitoring to study Okinawa’s “Soundscape”

At every OKEON site there is a small green box attached to a tree. These boxes are acoustic monitors, and they are recording natural sounds almost constantly. As part of the OKEON project, we use these natural sound recordings, or “soundscapes”, as a way of monitoring biodiversity.

Sam Ross sets up an acoustic monitoring device at the OIST field site.

We collect more than 1 terabyte of audio data every week. If you wanted to listen to all of the recordings we’ve made so far, it would take you about 8 years… if you listened all day and never went to sleep. To sort through all this audio data, we use two approaches. First, we break the sounds up into sounds at different frequencies (i.e., pitch). This lets us get a big picture view of when and where animals are active on Okinawa. Second, we use machine learning to train our computers to detect species in which we are interested. This helps us understand more about which particular species are in each area of the island, and how their behavior varies across the year.

In many parts of Okinawa, humans and nature live close together. Managing this interaction is important for preserving wild populations of plants and animals.

Ultimately, our project aims to understand the ways that human activity affects Okinawa’s wildlife, and how we can better protect these species in the future. For more information (including videos), please see the OIST press release. A link to the study can be found here.

Listening to the sounds of nature: switching on OIST’s acoustic monitoring network

February 14th is Valentine’s Day, and for birds living in Okinawa it’s the perfect time to start thinking about building a nest. In warm years like this one, the Tree Sparrow (スズメ) begins its breeding season around this time, followed by the Pacific Swallow (リュウキュウツバメ), the Japanese White-eye (メジロ), and the Japanese Tit (シジュウカラ). If you look closely at the eaves of houses around the island, you may notice the swallows beginning their nesting behavior.

Japanese Tit singing near Takeyanbaru; Photo Credit: Sam Ross

Researchers from arilab are monitoring the onset of the breeding season not only for birds, but also for frogs, crickets, and other organisms that communicate with sound. This is accomplished using a new acoustic monitoring network. While testing of this network has been ongoing for the last year, its installation and activation were completed last week, just in time for Valentine’s Day.

Acoustic Recorder; Photo Credit: Nick Friedman

OIST’s acoustic monitoring network produces more audio than scientists can analyze by ear: assuming you listened to the recordings every minute of every day, you would be twenty four years older by the time you finished a single year’s data. To fix this problem, OIST scientists are training computer models to recognize patterns of activity and to detect individual species of birds, frogs, and insects.

Shinji Iriyama, Ayumi Inoguchi, Sam Ross; Photo Credit: Nick Friedman

Written by Nicholas Friedman

Happy New Year! The First Rooster Call of 2017

rooster-call

On a small farm near the botanical garden in Okinawa City, a rooster sang its first song of 2017 – the “year of the rooster”. His was the first song of the dawn chorus, a daily event that arouses every type of bird sound on the island of Okinawa – from the sweet melody of the Ryukyu Robin (Akahige) to the harsh screeching of the Brown-eared Bulbul (Hiyodori).


– The first rooster call of 2017 –

This biological symphony has the sun as its conductor, as the conditions just before dawn are especially favorable for singing: the air is cool, the wind is quiet, and the light is low enough to afford a modicum of safety. For male birds, the dawn chorus provides a time for each individual to broadcast “I am still here”, and to assess which of its neighbors can say the same. For female birds, this can be a convenient time to determine which is the superior songster, or to share in the chorus.


– The dawn chorus –

Arilab’s post-doc Nick uses the rooster and its chorus as a way to monitor Okinawa’s ecosystems. The number of different bird species that join the rooster in its song each morning is an indicator of the ecosystem’s health. A varied and noisy morning suggests a healthy environment, whereas a silent morning suggests that some species have gone missing. The rooster’s song was recorded using a network of automated recorders placed in forests and fields across Okinawa.

– Content written by the OIST media section.