This is Bird Note.

For years, nature recordist Lang Elliott came up with clever ways to hear high-pitched bird songs, despite his high-frequency hearing loss.

Back in the 70s, he recorded birds on tape at high speed, then played the tape back at half speed.

Slowing the songs down also lowered their pitch.

And boom, oh my God, there's twice as many, three times as many birds in the forest singing now as I had perceived.

There's this flood of birdsong going on, and I'm detecting a very small part of it.

Lang's hearing loss is from a childhood accident, but many people lose their high frequency hearing due to aging.

So there are a lot of birders who, as they get older, they start losing, grasshopper sparrow or Cape May warbler, especially the high warblers.

Lang teamed up with a programmer to develop an app called Hear Birds Again.

Currently, it's only available for Apple devices, but it's able to take high-pitched bird songs and shift them down into a lower range.

The app works even better with a special binaural headset

so that users can tell whether a sound is coming from the right or left.

Detecting a bird without any spatial element is useful,

but what's fun is hearing it as if it's out there in a 3D environment,

being able to point toward it,

being able to actually go find it.

Learn more on our website, birdnote.org.

I'm Jonies Franklin.