Don't find the length of that challenging in any way. Interesting sound collage, like a teeming forest floor at the start. Never heard the term 'tertius auris' before, akin to the 'third eye' or e.e.cummings "the ears of my ears are open"? So you're presumably describing a kind of vocalisation of the ancestors, through the channel of a song which has travelled many years of voices...

Further to ethnogens and possible native pre-Christian remnants of Shamanism (as described in the so-called Witches 'nocturnal flight', and the herbs which may or may not have been utilised to induce this experience), I found this quite an interesting little volume, with rather tender artwork by Barbara Brouegel: Elizabeth Procter, Mary Sanford George Jacobs.
Plants of the Gods is also very interesting. As IMO is anything by those authors.