A New App Brings Birdsong Back to People With High-Frequency Hearing Loss

Lang Elliott didn’t realize the birdsong he was missing until the Worm-eating Warbler incident. In the 1970s, a professor noted the bird, but even standing beneath it, Elliott couldn’t pick out its lusty, high trills. “I’m watching it throw its head back and open its beak and sing its heart out. And I still don’t hear that bird,” he recalls. This “ear-opener” led to an experiment: Elliott slowed the speed—and lowered the pitch—of a recording he took in a forest. He was shocked at the birds he heard.

A test revealed Elliott, then 27, had high-frequency hearing loss, a condition caused by loud sounds or aging that one study found may affect nearly a third of U.S. adults under 70. “I was missing this huge part of the world of birdsong, not to mention insects,” he says, a crushing realization for the budding wildlife ecologist. The severity of his hearing loss above a certain frequency—due to a childhood accident with firecrackers, he realized—meant conventional hearing aids, which amplify sounds, wouldn’t help. Frustrated by his options, Elliott turned his dismay into a decades-long journey of developing tools that help birders reclaim avian soundscapes. 

First Elliott and electronic music pioneer Harald Bode adapted a commercial pitch-shifting machine from the music industry. Paired with a handmade headset outfitted with microphones and headphones to transmit 3D sound, he could sense the location and distance of a bird’s vocals. But after lugging the setup—designed for studios, not forests—around for a while, he wanted a more portable device. By this time, he had taken up an unexpected career traveling the world to capture sounds of birds and other wildlife, which he would eventually license for field guides, museums, and movies. He also thought others might benefit from his efforts. 

Enter the SongFinder, a boxy but mobile machine and double-mic headset, which Elliott and electrical engineer Herb Susmann debuted in 1991 for $750. By 2018, when production ended, it was pocket-sized and had garnered a small but devoted user base. Laura Erickson, 71, a user for more than a decade, found it “a game changer” for helping her enjoy her beloved LeConte’s Sparrows. A recent user, Jody Enck, 63, says the device “improved my quality of life and my income” because it allowed the environmental consultant to continue performing avian surveys. 

Now Elliott, 74, is releasing his latest iteration of the technology: a free iPhone app, Hear Birds Again, a labor of love developed with programmer Harold Mills. Like SongFinder, its algorithms instantly shift higher-pitched wildlife into frequencies low enough to be detected by people who still hear most human speech and some birdsong, such as a robin’s, but who struggle above roughly 3 kilohertz. App users can tune settings to suit their needs—lowering the pitch by different intervals to hear, say, a Brown Creeper, Blackburnian Warbler, or Northern Parula as necessary. To help birders truly experience the immersive “nirvana” of birdsong in stereo, Elliott designed another custom headset, fitted with microphones that connect to an iPhone and headphones that deliver high-quality, spatially oriented sound without interfering with other hearing.

“Looks a little geeky, but it works,” he says. The headset costs about $170 with shipping, through a partnership between his nonprofit and a U.K. online retailer. There’s some assembly required, or users can build their own DIY setup.

Of course, pitch-shifted birdsong doesn’t exactly sound the same, but the pattern remains. “A Parula Warbler that goes zee-UP still goes zee-UP,” says Elliott. He hopes that, with practice, users can relearn how to bird by ear, which can be transformational. Erickson, for example, has found success using SongFinder along with the pricey digital hearing aids that her audiologist programmed to augment birds, voices, and other sounds above a certain frequency. “These birds become old friends, and losing their voices is so sad,” she says. “When you get them back again, even if they sound a little different—well, I look way different than I did in my 20s.”

The world of birdsong could soon open further. In August, the FDA legalized over-the-counter hearing aids, a move anticipated to accelerate lower-cost devices for those with mild to moderate hearing loss and spur innovation opportunities, for birders and many others. And with the Hear Birds Again iPhone app’s release this month, Elliott is ready to pass the baton. Its open-source code, available on Github, allows for programmers to create an Android version—or take advantage of whatever technologies emerge next.

This story originally ran in the Winter 2022 issue as “Songs from Silence.” To receive our print magazine, become a member by making a donation today.