I like this one too. An earlier one of the original recordings[1] seem to feature 2 birds, if you want to know what that sounds like. Though I do like the cleaned-up version you linked with reverb added that gives it a mournful sound.

[1] From 1975, featuring 2 birds: https://macaulaylibrary.org/asset/6031

From 1986 (the last recording, 1 bird): https://macaulaylibrary.org/asset/228099