This has been on my mind for quite a while. 호롱호롱 seems to be the "default" word of choice for imitating the sound of mountain birds in many Korean children's songs, for instance,
But why? To my ears 호롱호롱 sounds nowhere like birds singing (unlike 뱃종뱃종 and 삐릿삐릿, which also appeared in the 3rd example above). I would rather say it is more like a snoring sound. Can anybody give me some hint how this word come to represent the mountain birds' sound?