I bought a secondhand professional audio recorder, then took it to national parks in Australia and Germany, in case I heard anything interesting. It was a bit of a learning experience, but I now have a library of half a dozen passable recordings.

The biggest problem was noise pollution: humans are noisy and everywhere; I never noticed until I started listening carefully for background noise. Traffic and building noise carries for huge distances.

I wrapped all the sounds up in a swiftUI interface, built around a curved video carousel.

I wanted to pay special attention to vision impaired users, so it all has VoiceOver support, and extra UI elements that can be turned on for vision impaired users.

It's free on the App Store if you want to take a look.