Each spring, scientists hide more than 1,600 lunchbox-size recorders across the forests of the Sierra Nevada range in the western U. S.
Until they're taken back at summer's end, these recorders record a million hours of audio （音频）, which often contains the hoots, barks, and whistles of the California spotted owl—valuable information about where the endangered species spends its time. But it's a lot of recordings for a human to go through. "There's no way we can listen to that —not even close," says Connor Wood, a researcher who co-leads the owl project at the K. Lisa Yang Center for Conservation Bioacoustics, part of the Cornell Lab of Ornithology in Ithaca, New York.
It turns out that this team actually can process this huge amount of data—they just need a little help from BirdNET, an AI-powered system launched in 2018 that can identify more than 6,000 species of birds, including the migration （迁徙） birds, across the globe just by their call.
"We need tools that are really flexible and capable of identifying as many acoustically （听觉上） active animals as possible," says Wood, whose lab developed BirdNET with the Chemnitz University of Technology in Germany. "I cannot stress enough the significant influence BirdNET has brought to bird research."
Two years later, the team launched the official BirdNET app, which allows people across the world to upload their own recordings from laptops or smartphones. Since then, BirdNET has gathered roughly 150 million high-quality bird sounds. With funding from the U. S. Forest Service and National Park Service, Wood and his team recently used BirdNET to create the first ecosystem-wide assessment of spotted owl populations across the Sierra Nevada, which increasingly face threats from enemy species or wildfires.
However, like most AI-based technology, these apps are not without drawbacks. In his recent study, ecologist Cristian Pérez-Granados, who works at the University of Alicante in Spain, reviewed a range of scientific literature on BirdNET. His research found that BirdNET didn't always register a bird's song, and sometimes misidentified it as another species, which results in "false positives".
