The Kauai 'o'o birdsong (Native to Hawaii, extinct since 1987) is my "Ainulindale," I really dont know how to explain why that is without getting too depressing. But to speak broadly on birdsongs generally, they are to me like little living pocket vibrations that release their frequences through song to, for a lack of better words "tune the atmosphere"

Thanks for posting this, though it is indeed very sad. But I agree, birdsong feels indeed like an echo of the Ainulindalë.
The song of the European blackbird has always captivated me. I’ll attach a recording of one I made in June ‘22 in our backyard:

French composer Olivier Messiaen was fascinated by birdsong and worked their song into many compositions. Here’s a couple of fragments from (apparently) a documentary: